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The American flamingo (''Phoenicopterus ruber'') is a large species of
flamingo
Flamingos or flamingoes are a type of Wader, wading bird in the Family (biology), family Phoenicopteridae, which is the only extant family in the order Phoenicopteriformes. There are four flamingo species distributed throughout the Americas ...
closely related to the
greater flamingo
The greater flamingo (''Phoenicopterus roseus'') is the most widespread and largest species of the flamingo family. It is found in Africa, the Indian subcontinent, the Middle East, and in southern Europe.
Taxonomy
The greater flamingo was desc ...
and
Chilean flamingo
The Chilean flamingo (''Phoenicopterus chilensis'') is a species of large flamingo at closely related to the American flamingo and the greater flamingo, with which it was sometimes considered conspecific. The species is listed as near threatened ...
native to the
Neotropics
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropics, tropical Ecoregion#Terrestrial, terrestrial ecoregions of the Americas and the entire South American temperat ...
. It was formerly considered
conspecific
Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species.
Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organ ...
with the greater flamingo, but that treatment is now widely viewed (e.g. by the
American
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
and
British Ornithologists' Unions) as incorrect due to a lack of evidence. It is also known as the Caribbean flamingo, although it is also present in the
Galápagos Islands
The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...
. It is the only flamingo that naturally inhabits
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
.
Distribution
![Phoenicopterus ruber MHNT](https://upload.wikimedia.org/wikipedia/commons/a/ab/Phoenicopterus_ruber_MHNT.jpg)
The American flamingo breeds in South America (in the Galápagos Islands of
Ecuador
Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...
, coastal
Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
and
Venezuela
Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
, and northern
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
), in the
West Indies
The West Indies is a subregion of North America, surrounded by the North Atlantic Ocean and the Caribbean Sea that includes 13 independent island countries and 18 dependencies and other territories in three major archipelagos: the Greater A ...
(
Trinidad and Tobago
Trinidad and Tobago (, ), officially the Republic of Trinidad and Tobago, is the southernmost island country in the Caribbean. Consisting of the main islands Trinidad and Tobago, and numerous much smaller islands, it is situated south of ...
,
Cuba
Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...
,
Jamaica
Jamaica (; ) is an island country situated in the Caribbean Sea. Spanning in area, it is the third-largest island of the Greater Antilles and the Caribbean (after Cuba and Hispaniola). Jamaica lies about south of Cuba, and west of His ...
,
Hispaniola
Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...
(the
Dominican Republic
The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares wit ...
and
Haiti
Haiti (; ht, Ayiti ; French: ), officially the Republic of Haiti (); ) and formerly known as Hayti, is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean Sea, east of Cuba and Jamaica, and ...
),
The Bahamas
The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...
, the
Virgin Islands
The Virgin Islands ( es, Islas Vírgenes) are an archipelago in the Caribbean Sea. They are geologically and biogeographically the easternmost part of the Greater Antilles, the northern islands belonging to the Puerto Rico Trench and St. Croix ...
, and the
Turks and Caicos Islands
The Turks and Caicos Islands (abbreviated TCI; and ) are a British Overseas Territory consisting of the larger Caicos Islands and smaller Turks Islands, two groups of tropical islands in the Lucayan Archipelago of the Atlantic Ocean and n ...
), and tropical areas of continental North America (along the northern coast of the
Yucatán Peninsula
The Yucatán Peninsula (, also , ; es, Península de Yucatán ) is a large peninsula in southeastern Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north ...
in
Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
, and
Cameron Parish, Louisiana
Cameron Parish (french: Paroisse de Cameron) is a parish in the southwest corner of the U.S. state of Louisiana. As of the 2020 census, the population was 5,617. The parish seat is Cameron. Although it is the largest parish by area in Louisia ...
, and extreme
southern Florida
South Florida is the southernmost region of the U.S. state of Florida. It is one of Florida's three most commonly referred to directional regions; the other two are Central Florida and North Florida. South Florida is the southernmost part of th ...
in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
). It is a vagrant to
Puerto Rico
Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...
,
Anguilla
Anguilla ( ) is a British Overseas Territory in the Caribbean. It is one of the most northerly of the Leeward Islands in the Lesser Antilles, lying east of Puerto Rico and the Virgin Islands and directly north of Saint Martin. The territo ...
,
Barbados
Barbados is an island country in the Lesser Antilles of the West Indies, in the Caribbean region of the Americas, and the most easterly of the Caribbean Islands. It occupies an area of and has a population of about 287,000 (2019 estimate). ...
, and
Honduras
Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...
.
The population in the Galápagos Islands differs genetically from that in the Caribbean; the Galápagos flamingos are significantly smaller, exhibit
sexual dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
in body shape, and lay smaller eggs. They are sometimes separated as ''Phoenicopterus ruber glyphorhynchus''.
[
Its preferred habitats are similar to those of its relatives: saline ]lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') a ...
s, mudflat
Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal fl ...
s, and shallow, brackish
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...
coastal or inland lakes. An example habitat is the Petenes mangroves ecoregion of the Yucatán.[
]
In Florida
The American flamingo is also found in South Florida
South Florida is the southernmost region of the U.S. state of Florida. It is one of Florida's three most commonly referred to directional regions; the other two are Central Florida and North Florida. South Florida is the southernmost part of th ...
and the Florida Keys
The Florida Keys are a coral cay archipelago located off the southern coast of Florida, forming the southernmost part of the continental United States. They begin at the southeastern coast of the Florida peninsula, about south of Miami, and e ...
, both of which were likely the northernmost extent of its distribution. The existence of flamingo eggs in museum collections labeled as collected from Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
indicates that they likely nested there as well. Since the arrival of Europeans, the population started to decline, up until the 1900s, where it was considered completely extirpated. During the 1950s, birds from the captive population at Hialeah Park frequently escaped, thus leading to the conclusion that all modern flamingos in Florida were escapees, although at least one bird banded as a chick in the Yucatán Peninsula
The Yucatán Peninsula (, also , ; es, Península de Yucatán ) is a large peninsula in southeastern Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north ...
has been sighted in Everglades National Park
Everglades National Park is an American national park that protects the southern twenty percent of the original Everglades in Florida. The park is the largest tropical wilderness in the United States and the largest wilderness of any kind east ...
.
However, a study published in 2018, involving an abandoned young flamingo named Conchy found in Key West, indicates that the occasional flamingos observed in parts of Florida are in fact natives, with some even permanently staying in Florida Bay
Florida Bay is the bay located between the southern end of the Florida mainland (the Florida Everglades) and the Florida Keys in the United States. It is a large, shallow estuary that while connected to the Gulf of Mexico, has limited exchange o ...
year-round. The study also indicated that these flamingos may be increasing in population and reclaiming their lost range, slowly but steadily returning home. Large flocks of flamingos are still known to visit Florida from time to time, most notably in 2014, when a very large flock of over 147 flamingos temporarily stayed at Stormwater Treatment Area 2, on Lake Okeechobee
Lake Okeechobee (), also known as Florida's Inland Sea, is the largest freshwater lake in the U.S. state of Florida. It is the tenth largest natural freshwater lake among the 50 states of the United States and the second-largest natural freshwat ...
, with a few returning the following year. From a distance, untrained eyes can also confuse it with the roseate spoonbill
The roseate spoonbill (''Platalea ajaja'') is a gregarious wading bird of the ibis and spoonbill family, Threskiornithidae. It is a resident breeder in both South and North America.
Taxonomy
The roseate spoonbill is sometimes placed in its own ...
.
Description
The American flamingo is a large wading bird
245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots
Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
with reddish-pink plumage. Like all flamingos, it lays a single chalky-white egg on a mud mound, between May and August; incubation until hatching takes from 28 to 32 days; both parents brood
Brood may refer to:
Nature
* Brood, a collective term for offspring
* Brooding, the incubation of bird eggs by their parents
* Bee brood, the young of a beehive
* Individual broods of North American Periodical Cicadas:
** Brood X, the largest b ...
their young. They may reach sexual maturity between 3 and 6 years of age, though usually they do not reproduce until they are 6 years old. Their life expectancy of 40 years is one of the longest in birds.
Adult American flamingos are smaller on average than greater flamingo
The greater flamingo (''Phoenicopterus roseus'') is the most widespread and largest species of the flamingo family. It is found in Africa, the Indian subcontinent, the Middle East, and in southern Europe.
Taxonomy
The greater flamingo was desc ...
s, but are the largest flamingos in the Americas. They measure from tall. The males weigh an average of , while females average . Most of its plumage is pink, giving rise to its earlier name of rosy flamingo and differentiating adults from the much paler greater flamingo. The wing coverts are red, and the primary and secondary flight feathers are black. The bill is pink and white with an extensive black tip. The legs are entirely pink. The call is a goose
A goose ( : geese) is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera ''Anser'' (the grey geese and white geese) and '' Branta'' (the black geese). Some other birds, mostly related to the ...
-like honking.
It is one of the species to which the applies.
Mating and bonding behaviors
Mating and bonding behaviors of ''P. ruber'' individuals have been extensively studied in captivity. The American flamingo is usually monogamous when selecting a nest site, and incubating and raising young; however, extra-pair copulations are frequent.
While males usually initiate courtship, females control the process. If interest is mutual, a female walks by the male, and if the male is receptive, he walks with her. Both parties make synchronized movements until one member aborts this process. For low-intensity courtships, males and females walk in unison with their heads raised. In high-intensity courtships, males and females walk at a quick pace with their heads dropped in a false feeding posture. This high-intensity courtship stops at any point if either bird turns and the other does not follow, the heads are raised, unison movements are stopped, or the pace of movement is slowed. If the female is ultimately receptive to copulation, she stops walking and presents for the male. Long-term pairs do not frequently engage in courtship behaviors or in-group display. Pairs often stand, sleep, and eat in close proximity.
Courtship is most often seen among individuals that change partners often or are promiscuous. A spectrum of pairing relationships is seen. Some birds have a long-term partner throughout the year; others form pairs during periods of courtship and nest attendance. How long a relationship lasts is affected by many factors, including addition and removal of adults, maturation of juveniles, and occurrence of trios and quartets. In most pairs, both individuals usually construct and defend the nest site. In rare cases, one individual undertakes both duties. Within trios, the dominant pair begins the nesting process by choosing and then defending the site.
For trios with one male and two females, the subordinate female is tolerated by the male, but often fights with the dominant female. If two females share a nest and both lay an egg, one female will try to destroy the other egg or roll it out of the nest. For trios with two males and one female, the subordinate male is tolerated by both individuals and often becomes the primary incubator and caregiver of the chicks. For quartets, the dominant male and two females take care of the nest, while the subordinate male remains around the periphery, never gaining access to the nest. Less animosity is observed between the dominant and subordinate females in quartets compared to trios.[
The egg is attended constantly and equally by alternating parents. Chicks at the nest are attended constantly by alternating parents, up to 7–11 days of age. Most attentive periods during incubation and brooding last 21–60 hours, both in the case where the ‘off-duty’ parents remain in the same lagoon to feed, or (when breeding occurs in lagoons deficient in food), they fly to other lagoons to feed. Nest reliefs during incubation take place predominantly in late afternoon, or early morning.
]
The time for receiving food from parents decreases from hatching to about 105 days, and the decrease is greatest after the chicks have left the nest at 7–11 days to band into crèches. The frequency and the duration of feeds by male and female partners do not differ significantly. After chicks have left the nest, feeds are predominantly nocturnal.
Adaptations
The American flamingo has adapted to its shallow-water environment in several ways. It has evolved long legs and large webbed feet to wade and stir up the bottom of the water bed to bring up their food source to then be retrieved. To feed, it has evolved a specialized beak which is hooked downward and features marginal lamella
Lamella (plural lamellae) means a small plate or flake in Latin, and in English may refer to:
Biology
* Lamella (mycology), a papery rib beneath a mushroom cap
* Lamella (botany)
* Lamella (surface anatomy), a plate-like structure in an animal
...
e on the upper mandible, and inner and outer lamellae on both the upper and lower mandibles. These are adapted for filtering out differently sized food from water.[ Depending on the food source in their area, diets depend on the exact ]morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
* Morphology (archaeology), study of the shapes or forms of artifacts
* Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
of their beaks on what can and cannot be strained out of them. The American flamingos’ diet consists of small crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s, mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...
s, some worm
Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always).
Worms vary in size from microscopic to over in length for marine polychaete wor ...
s, nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
s, insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s and their larvae, small fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
, widgeon grass, seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s and algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
. They are also known to consume mud from which they are able to get microorganisms and bacteria and obtain nutrients. It submerges its head under water to retrieve its food, and may have its head under water for long times, which requires it to hold its breath. Factors which affect the habitat choice of American flamingos are environmental temperatures, water depth, food source, accessibility of an area, and the presence of vegetation beds in feeding areas. If available food items do not meet the needs of the flamingos or the temperature is not appropriate to their requirements, they move to a better feeding or more temperate area.
Osmoregulation
The role of osmoregulation
Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration o ...
—the maintenance of a precise balance of solute and water concentrations within the body—is performed by a number of bodily functions working together. In ''P. ruber'', the kidney
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...
, the lower gastrointestinal tract, and the salt glands
The salt gland is an organ for excreting excess salts. It is found in the cartilaginous fishes subclass elasmobranchii (sharks, rays, and skates), seabirds, and some reptiles. Salt glands can be found in the rectum of sharks. Birds and reptiles ...
work together to maintain the homeostasis
In biology, homeostasis (British English, British also homoeostasis) Help:IPA/English, (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physics, physical, and chemistry, chemical conditions maintained by organism, living systems. Thi ...
between ions and fluids. In mammals, the kidneys and urinary bladder are the primary organs used in osmoregulation. Birds, however, lack a urinary bladder and must compensate using these three organs.
American flamingos are saltwater birds that ingest food with a high salt content and mostly drink salt water (with an osmolarity
Osmotic concentration, formerly known as osmolarity, is the measure of solute concentration, defined as the number of osmoles (Osm) of solute per litre (L) of solution (osmol/L or Osm/L). The osmolarity of a solution is usually expressed as Osm/L ...
of usually 1000), hyperosmotic
In chemical biology, tonicity is a measure of the effective osmotic pressure gradient; the water potential of two solutions separated by a partially-permeable cell membrane. Tonicity depends on the relative concentration of selective membrane- ...
to the bodies cells . Also, though not commonly, they can drink fresh water at near-boiling temperatures from geysers. From their high-salt diet, they would lose more water and have a greater salt uptake. One way in which they osmoregulate is through the use of a salt gland
The salt gland is an organ for excreting excess salts. It is found in the cartilaginous fishes subclass elasmobranchii (sharks, rays, and skates), seabirds, and some reptiles. Salt glands can be found in the rectum of sharks. Birds and reptile ...
, which is found in their beaks.[ This salt gland helps excrete excess salt from the body through the nasal openings in the flamingo's beaks. When these birds consume salt, the osmolarity increases in the blood plasma through the gut. This causes water to move out of the cells, increasing extracellular fluids. Both these changes, in turn, activate the salt glands of the bird,][ but before any activity occurs in the salt glands, the kidney has to reabsorb the ingested sodium from the small intestine. As seen in other saltwater birds, the fluid that is excreted has been seen to have an osmolarity greater than that of the salt water, but this varies with salt consumption and body size.][
As food and saltwater are ingested, sodium and water absorption begins through the walls of the gut and into the ]extracellular fluid
In cell biology, extracellular fluid (ECF) denotes all body fluid outside the cells of any multicellular organism. Total body water in healthy adults is about 60% (range 45 to 75%) of total body weight; women and the obese typically have a lower ...
. Sodium is then circulated to the kidney, where the plasma undergoes filtration by the renal glomerulus
The glomerulus (plural glomeruli) is a network of small blood vessels (capillaries) known as a ''tuft'', located at the beginning of a nephron in the kidney. Each of the two kidneys contains about one million nephrons. The tuft is structurally s ...
. Although birds' kidneys tend to be larger in size, they are inefficient in producing concentrated urine that is significantly hyperosmotic to their blood plasma. This form of secretion would cause dehydration from water loss. Therefore, sodium and water are reabsorbed into the plasma by renal tubules
The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure ...
. This increase in osmotic plasma levels causes extracellular fluid volume to increase, which triggers receptors in both the brain and heart. These receptors then stimulate salt gland secretion and sodium is able to efficiently leave the body through the nares while maintaining a high body water level.[
Flamingos, like many other marine birds, have a high saline intake, yet even the glomular filtration rate (GFR) remains unchanged. This is because of the salt glands; high concentrations of sodium are present in the renal filtrate, but can be reabsorbed almost completely where it is excreted in high concentrations in the salt glands.][ Renal reabsorption can be increased through the output of the ]antidiuretic
An antidiuretic is a substance that helps to control fluid balance in an animal's body by reducing urination, opposing diuresis. Its effects are opposite that of a diuretic. The major endogenous antidiuretics are antidiuretic hormone (ADH; also ca ...
hormone called arginine vasotocin (AVT). AVT opens protein channels in the collection ducts of the kidney called aquaporins. Aquaporins
Aquaporins, also called water channels, are channel proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells, mainly facilitating transport of water between cells. The cell membranes of a va ...
increase the membrane permeability to water, as well as causes less water to move from the blood and into the kidney tubules.
Specialized osmoregulatory cells and transport mechanisms
The salt gland
The salt gland is an organ for excreting excess salts. It is found in the cartilaginous fishes subclass elasmobranchii (sharks, rays, and skates), seabirds, and some reptiles. Salt glands can be found in the rectum of sharks. Birds and reptile ...
used by the American flamingo has two segments, a medial and lateral segment. These segments are tube shaped glands that consist of two cell types. The first is the cuboidal – peripheral cells which are small, triangular shaped cells which have only a few mitochondria
A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...
. The second specialized cells are the principal cells which are found down the length of the secretory tubules, and are rich in mitochondria.[ These cells are similar to the mitochondria rich cells found in ]teleost fish
Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts ), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of all extant species of fish. Tel ...
.
These cells within the salt gland employ several types of transport mechanisms that respond to osmoregulatory
Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration o ...
loads.[ Sodium-Potassium ]ATPase
ATPases (, Adenosine 5'-TriPhosphatase, adenylpyrophosphatase, ATP monophosphatase, triphosphatase, SV40 T-antigen, ATP hydrolase, complex V (mitochondrial electron transport), (Ca2+ + Mg2+)-ATPase, HCO3−-ATPase, adenosine triphosphatase) are ...
works with a Sodium-Chloride cotransporter Cotransporters are a subcategory of membrane transport proteins (transporters) that couple the favorable movement of one molecule with its concentration gradient and unfavorable movement of another molecule against its concentration gradient. They e ...
(also known as the NKCC), and a basal potassium channel to secrete salt (NaCl) into secretory tubes.[ The ATPase uses energy from ATP to pump three sodium ions out of the cell and two potassium ions into the cell. The ]potassium channel
Potassium channels are the most widely distributed type of ion channel found in virtually all organisms. They form potassium-selective pores that span cell membranes. Potassium channels are found in most cell types and control a wide variety of cel ...
allows potassium ions to diffuse out of the cell. The cotransporter pumps one sodium, potassium and two chloride ions into the cell. The chloride ion diffuses through the apical membrane into the secretory tube and the sodium follows via a paracellular
Paracellular transport refers to the transfer of substances across an epithelium by passing through the intercellular space ''between'' the cells. It is in contrast to transcellular transport, where the substances travel ''through'' the cell, pass ...
route.[ This is what forms the ]hyperosmotic
In chemical biology, tonicity is a measure of the effective osmotic pressure gradient; the water potential of two solutions separated by a partially-permeable cell membrane. Tonicity depends on the relative concentration of selective membrane- ...
solution within the salt glands.
Circulatory system
Although there has been little investigation on the specific circulatory and cardiovascular system of the phoenicopteridae, they possess the typical features of an avian circulatory system. As is seen in other aves, the flamingo's circulatory system is closed maintaining a separation of oxygenated and deoxygenated blood. This maximizes their efficiency to meet their high metabolic needs during flight. Due to this need for increased cardiac output, the avian heart tends to be larger in relation to body mass than what is seen in most mammals.
Heart type and features
The avian circulatory system is driven by a four-chambered, myogenic heart contained in a fibrous pericardial sac. This pericardial sac is filled with a serous fluid
In physiology, serous fluid or serosal fluid (originating from the Medieval Latin word ''serosus'', from Latin ''serum'') is any of various body fluids resembling Serum (blood), serum, that are typically pale yellow or transparent and of a benign ...
for lubrication.[ The heart itself is divided into a right and left half, each with an ]atrium
Atrium may refer to:
Anatomy
* Atrium (heart), an anatomical structure of the heart
* Atrium, the genital structure next to the genital aperture in the reproductive system of gastropods
* Atrium of the ventricular system of the brain
* Pulmona ...
and ventricle. The atrium and ventricles of each side are separated by atrioventricular valves
A heart valve is a one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart v ...
which prevent back flow from one chamber to the next during contraction. Being myogenic, the hearts pace is maintained by pacemaker cells found in the sinoatrial node, located on the right atrium. The sinoatrial node
The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approximat ...
uses calcium to cause a depolarizing signal transduction pathway from the atrium through right and left atrioventricular bundle which communicates contraction to the ventricles. The avian heart also consists of muscular arches that are made up of thick bundles of muscular layers. Much like a mammalian heart, the avian heart is composed of endocardial
The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the endothelial cells that line blood vessels. The endocardium also provides protection to the val ...
, myocardial
Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that ...
and epicardial layers.[ The atrium walls tend to be thinner than the ventricle walls, due to the intense ventricular contraction used to pump oxygenated blood throughout the body.
]
Organization of circulatory system
Similar to the atrium, the arteries are composed of thick elastic muscles to withstand the pressure of the ventricular constriction, and become more rigid as they move away from the heart. Blood moves through the arteries, which undergo vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessel ...
, and into arterioles which act as a transportation system to distribute primarily oxygen as well as nutrients to all tissues of the body.[ As the arterioles move away from the heart and into individual organs and tissues they are further divided to increase surface area and slow blood flow. Travelling through the arterioles blood moves into the capillaries where gas exchange can occur. Capillaries are organized into capillary beds in tissues, it is here that blood exchanges oxygen for carbon dioxide waste. In the capillary beds blood flow is slowed to allow maximum diffusion of oxygen into the tissues. Once the blood has become deoxygenated it travels through venules then veins and back to the heart. Veins, unlike arteries, are thin and rigid as they do not need to withstand extreme pressure. As blood travels through the venules to the veins a funneling occurs called ]vasodilation
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, ...
bringing blood back to the heart.[ Once the blood reaches the heart it moves first into the right atrium, then the left ventricle to be pumped through the lungs for further gas exchange of carbon dioxide waste for oxygen. Oxygenated blood then flows from the lungs through the left atrium to the left ventricle where it is pumped out to the body. With respect to thermoregulation, the American flamingo has highly ]vascularized
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting ...
feet that use a countercurrent exchange
Countercurrent exchange is a mechanism occurring in nature and mimicked in industry and engineering, in which there is a crossover of some property, usually heat or some chemical, between two flowing bodies flowing in opposite directions to each ...
system in their legs and feet. This method of thermoregulation keeps a constant gradient
In vector calculus, the gradient of a scalar-valued differentiable function of several variables is the vector field (or vector-valued function) \nabla f whose value at a point p is the "direction and rate of fastest increase". If the gradi ...
between the veins and arteries that are in close proximity in order to maintain heat within the core and minimize heat loss or gain in the extremities. Heat loss is minimized while wading in cold water, while heat gain is minimized in the hot temperatures during rest and flight.[
]
Physical and chemical properties of pumping blood
Avian hearts are generally larger than mammalian hearts when compared to body mass. This adaptation allows more blood to be pumped to meet the high metabolic need associated with flight. Birds, like the flamingo, have a very efficient system for diffusing oxygen into the blood; birds have a ten times greater surface area to gas exchange volume than mammals. As a result, birds have more blood in their capillaries per unit of volume of lung than a mammal.[ The American flamingo's four-chambered heart is myogenic, meaning that all the muscle cells and fibers have the ability to contract rhythmically.][ The rhythm of contraction is controlled by the pace maker cells which have a lower threshold for depolarization. The wave of electrical depolarization initiated here is what physically starts the heart's contractions and begins pumping blood. Pumping blood creates variations in blood pressure and as a result, creates different thicknesses of blood vessels. The Law of LaPlace can be used to explain why arteries are relatively thick and veins are thin.
]
Blood composition
It was widely thought that avian blood had special properties which attributed to a very efficient extraction and transportation of oxygen in comparison to mammalian blood. This is not true; there is no real difference in the efficiency of the blood, and both mammals and birds use a hemoglobin
Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...
molecule as the primary oxygen carrier with little to no difference in oxygen carrying capacity.[ Captivity and age have been seen to have an effect on the blood composition of the American flamingo. A decrease in ]white blood cell
White blood cells, also called leukocytes or leucocytes, are the cell (biology), cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and de ...
numbers was predominate with age in both captive and free living flamingos, but captive flamingos showed a higher white blood cell count than free living flamingos. One exception occurs in free living flamingos with regards to white blood cell count. The number of eosinophils
Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. A ...
in free living birds are higher because these cells are the ones that fight off parasites with which a free living bird may have more contact than a captive one. Captive birds showed higher hematocrit
The hematocrit () (Ht or HCT), also known by several other names, is the volume percentage (vol%) of red blood cells (RBCs) in blood, measured as part of a blood test. The measurement depends on the number and size of red blood cells. It is norm ...
and red blood cell numbers than the free living flamingos, and a blood hemoglobin increase was seen with age. An increase in hemoglobin would correspond with an adults increase in metabolic needs. A smaller mean cellular volume recorded in free living flamingos coupled with similar mean hemoglobin content between captive and free living flamingos could show different oxygen diffusion characteristics between these two groups. Plasma chemistry remains relatively stable with age but lower values of protein content, uric acid, cholesterol, triglycerides, and phospholipids were seen in free living flamingos. This trend can be attributed to shortages and variances in food intake in free living flamingos.[
]
Blood composition and osmoregulation
Avian erythrocytes
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...
(red blood cells) have been shown to contain approximately ten times the amount of taurine
Taurine (), or 2-aminoethanesulfonic acid, is an organic compound that is widely distributed in animal tissues. It is a major constituent of bile and can be found in the large intestine, and accounts for up to 0.1% of total human body weight. It ...
(an amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
) as mammal erythrocytes. Taurine has a fairly large list of physiological functions; but in birds, it can have an important influence on osmoregulation. It helps the movement of ions in erythrocytes by altering the permeability of the membrane and regulating osmotic pressure within the cell. The regulation of osmotic pressure is achieved by the influx or efflux of taurine relative to changes in the osmolarity of the blood. In a hypotonic environment, cells will swell and eventually shrink; this shrinkage is due to efflux of taurine. This process also works in the opposite way in hypertonic environments. In hypertonic environments cells tend to shrink and then enlarge; this enlargement is due to an influx in taurine, effectively changing the osmotic pressure.[ This adaptation allows the flamingo to regulate between differences in salinity.
]
Respiratory system
Relatively few studies have focused on the flamingo respiratory system
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies grea ...
, however little to no divergences from the standard avian
Avian may refer to:
*Birds or Aves, winged animals
*Avian (given name) (russian: Авиа́н, link=no), a male forename
Aviation
*Avro Avian, a series of light aircraft made by Avro in the 1920s and 1930s
*Avian Limited, a hang glider manufacture ...
anatomical design have occurred in their evolutionary history. Nevertheless, some physiological differences do occur in the flamingo and structurally similar species.
The respiratory system is not only important for efficient gas exchange
Gas exchange is the physical process by which gases move passively by Diffusion#Diffusion vs. bulk flow, diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liqui ...
, but for thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
and vocalization.[ Thermoregulation is important for flamingos as they generally live in warm habitats and their plush plumage increases body temperature. Heat loss is accomplished through thermal polypnea (panting), that is an increase in respiratory rate. It has been seen that the medulla, hypothalamus and mid-brain are involved in the control of panting, as well through the Hering-Breuer reflex that uses stretch receptors in the lungs, and the ]vagus nerve
The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right ...
.[ This effect of the panting is accelerated by a process called ]gular
Gular is of or pertaining to the throat
In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebrae. It contains the pharynx and larynx. An important section of it is the epiglottis, separatin ...
fluttering;[ rapid flapping of membranes in the throat which is synchronized with the movements of the thorax. Both of these mechanisms promote evaporative heat loss, which allows for the bird to push out warm air and water from the body. Increases in respiratory rate would normally cause ]respiratory alkalosis
Respiratory alkalosis is a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a concurrent reduction in arterial levels of carbon dioxide. This condition is one of the four primary di ...
because carbon dioxide levels are rapidly dropping in the body, but the flamingo is able to bypass this, most likely through a shunt mechanism,[ which allow it to still maintain a sustainable partial pressure of carbon dioxide in the blood. Since the avian ]integument
In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind.
Etymology
The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...
is not equipped with sweat glands, cutaneous cooling is minimal. Because the flamingo's respiratory system is shared with multiple functions, panting must be controlled to prevent hypoxia.
For a flamingo, having such a long neck means adapting to an unusually long trachea
The trachea, also known as the windpipe, is a Cartilage, cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends ...
. Tracheas are an important area of the respiratory tract; aside from directing air in and out of the lungs, it has the largest volume of dead space
''Dead Space'' is a science fiction/ horror media franchise created by Glen Schofield and Michael Condrey, developed by Visceral Games, and published and owned by Electronic Arts. The franchise's chronology is not presented in a linear format; ...
in the tract. Dead space in avians is around 4.5 times higher in mammals of roughly the same size.[ In particular, flamingos have a trachea that is longer than its body length][ with 330 cartilaginous rings.][ As a result, they have a calculated dead space twice as high as another bird of the same size.][ To compensate for the elongation, they usually breathe in deep, slow patterns.][
One hypothesis for the bird's adaptation to ]respiratory alkalosis
Respiratory alkalosis is a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a concurrent reduction in arterial levels of carbon dioxide. This condition is one of the four primary di ...
is tracheal coiling. Tracheal coiling is an overly long extension of the trachea
The trachea, also known as the windpipe, is a Cartilage, cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends ...
and can often wrap around the bird's body. When faced with a heat load, birds often use thermal panting and this adaptation of tracheal coiling allows ventilation of non-exchange surfaces which can enable the bird to avoid respiratory alkalosis. The flamingo uses a "flushout" pattern of ventilation where deeper breaths are essentially mixed in with shallow panting to flush out carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
and avoid alkalosis. The increased length of the trachea provides a greater ability for respiratory evaporation and cooling off without hyperventilation.[
]
Thermoregulation
Thermoregulation is a matter of keeping a consistent body temperature regardless of the surrounding ambient temperature
Colloquially, "room temperature" is a range of air temperatures that most people prefer for indoor settings. It feels comfortable to a person when they are wearing typical indoor clothing. Human comfort can extend beyond this range depending on ...
. Flamingos require both methods of efficient heat retention and release. Even though the American flamingo resides mainly close to the equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
where there is relatively little fluctuation in temperature, seasonal and circadian variations in temperature must be accounted for.
Like all animals, flamingos maintain a relatively constant basal metabolic rate
Basal metabolic rate (BMR) is the rate of food energy, energy expenditure per unit time by endotherm, endothermic animals at rest. It is reported in energy units per unit time ranging from watt (joule/second) to ml O2/min or joule per hour per kg b ...
(BMR); the metabolic rate of an animal in its thermoneutral zone (TNZ) while at rest. The BMR is a static rate which changes depending on factors such as the time of day or seasonal activity. Like most other birds, basic physiological adaptations control both heat loss in warm conditions and heat retention in cooler conditions. Using a system of countercurrent blood flow, heat is efficiently recycled through the body rather than being lost through extremities such as the legs and feet.
Living in the equatorial region of the world, the American flamingo has little variation in seasonal temperature changes. However, as a homeothermic
Homeothermy, homothermy or homoiothermy is thermoregulation that maintains a stable internal body temperature regardless of external influence. This internal body temperature is often, though not necessarily, higher than the immediate environmen ...
endotherm
An endotherm (from Greek ἔνδον ''endon'' "within" and θέρμη ''thermē'' "heat") is an organism that maintains its body at a metabolically favorable temperature, largely by the use of heat released by its internal bodily functions inste ...
it is still faced with the challenge of maintaining a constant body temperature while being exposed to both the day (light period) and night (dark period) temperatures of its environments. ''Phoenicopterus ruber'' have evolved a number of thermoregulatory mechanisms to keep itself cool during the light period and warm during the dark period without expending too much energy. The American flamingo has been observed in a temperature niche between .[ In order to prevent water loss through evaporation when temperatures are elevated the flamingo will employ ]hyperthermia
Hyperthermia, also known simply as overheating, is a condition in which an individual's body temperature is elevated beyond normal due to failed thermoregulation. The person's body produces or absorbs more heat than it dissipates. When extreme ...
as a nonevaporative heat loss method keeping its body temperature between .[ This allows heat to leave the body by moving from an area of high body temperature to an area of a lower ambient temperature. Flamingos are also able to use evaporative heat loss methods such as, cutaneous evaporative heat loss and respiratory evaporative heat loss. During cutaneous heat loss, ''Phoenicopterus ruber'' relies on evaporation off of the skin to reduce its body temperature. This method is not very efficient as it requires evaporation to pass through the plumage. A more efficient way to reduce its body temperature is through respiratory evaporative heat loss, where the flamingo engages in panting to expel excessive body heat. During the dark period the flamingos tend to tuck their heads beneath their wing to conserve body heat. They may also elicit ]shivering
Shivering (also called shuddering) is a bodily function in response to cold and extreme fear in warm-blooded animals. When the core body temperature drops, the shivering reflex is triggered to maintain homeostasis. Skeletal muscles begin to s ...
as a means of muscular energy consumption to produce heat as needed.[
]
One of the most distinctive attribute of ''P. ruber'' is its unipedal stance, or the tendency to stand on one leg. While the purpose of this iconic posture remains ultimately unanswered, strong evidence supports its function in regulating body temperature.[ Like most birds, the largest amount of heat is lost through the legs and feet;][ having long legs can be a major disadvantage when temperatures fall and heat retention is most important. By holding one leg up against the ]ventral
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...
surface of the body, the flamingo lowers the surface area by which heat exits the body.[ Moreover, it has been observed that during periods of increased temperatures such as mid-day, flamingos will stand on both legs. Holding a bipedal stance multiplies the amount of heat lost from the legs and further regulates body temperature.][
]
Migration
Like other flamingo species, American flamingos will migrate short distances to ensure that they get enough food or because their current habitat has been disturbed in some way. One habitat disturbance that has been observed to cause flamingos to leave their feeding grounds is elevated water levels. These conditions make it difficult for ''Phoenicopterus ruber'' to wade, hindering their ability to access food. The flamingos will then abandon their feeding grounds in search of an alternate food source.[ While the flights are not as long as other ]migratory birds
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by ...
, flamingos still fly for periods without eating.
References
Further reading
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External links
3D computed tomographic animations showing the anatomy of the head of the Caribbean Flamingo
Greater Flamingo Species text in The Atlas of Southern African Birds
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{{Taxonbar, from=Q208004
American flamingo
The American flamingo (''Phoenicopterus ruber'') is a large species of flamingo closely related to the greater flamingo and Chilean flamingo native to the Neotropics. It was formerly considered conspecific with the greater flamingo, but that tre ...
American flamingo
The American flamingo (''Phoenicopterus ruber'') is a large species of flamingo closely related to the greater flamingo and Chilean flamingo native to the Neotropics. It was formerly considered conspecific with the greater flamingo, but that tre ...
Birds of the Turks and Caicos Islands
Birds of the United States
Birds of the Dominican Republic
Birds of Colombia
Birds of Venezuela
Birds of Ecuador
Birds of the Caribbean
National symbols of the Bahamas
American Flamingo
The American flamingo (''Phoenicopterus ruber'') is a large species of flamingo closely related to the greater flamingo and Chilean flamingo native to the Neotropics. It was formerly considered conspecific with the greater flamingo, but that tre ...
American flamingo
The American flamingo (''Phoenicopterus ruber'') is a large species of flamingo closely related to the greater flamingo and Chilean flamingo native to the Neotropics. It was formerly considered conspecific with the greater flamingo, but that tre ...