manta rays
   HOME

TheInfoList



OR:

Manta rays are large
ray Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gr ...
s belonging to the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''
Mobula ''Mobula'' is a genus of rays in the family Mobulidae that is found worldwide in tropical and warm, temperate seas. Some authorities consider this to be a subfamily of the Myliobatidae (eagle rays). Their appearance is similar to that of manta ...
'' (formerly its own
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''Manta''). The larger species, '' M. birostris'', reaches in width, while the smaller, '' M. alfredi'', reaches . Both have triangular
pectoral fins Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as see ...
, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Myliobatiformes (
stingray Stingrays are a group of sea rays, which are cartilaginous fish related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae ...
s and relatives) and are placed in the
family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Myliobatidae (eagle rays). They have the largest brains and brain to body ratio of all fish, and can pass the
mirror test The mirror test—sometimes called the mark test, mirror self-recognition (MSR) test, red spot technique, or rouge test—is a behavioral technique developed in 1970 by American psychologist Gordon Gallup Jr. as an attempt to determine whether an ...
. Mantas are found in warm
temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...
,
subtropical The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north a ...
and
tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...
waters. Both species are
pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...
; ''M. birostris'' migrates across open oceans, singly or in groups, while ''M. alfredi'' tends to be resident and coastal. They are
filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...
s and eat large quantities of
zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
, which they gather with their open mouths as they swim. However, research suggests that the majority of their diet (73%) actually comes from mesopelagic sources.
Gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pr ...
lasts over a year and mantas
give birth Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births globa ...
to live pups. Mantas may visit
cleaning station A cleaning station is a location where aquatic life congregate to be cleaned by smaller creatures. Such stations exist in both freshwater and marine environments, and are used by animals including fish, sea turtles and hippos, referred to as cli ...
s for the removal of
parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...
s. Like whales, they
breach Breach, Breached, or The Breach may refer to: Places * Breach, Kent, United Kingdom * Breach, West Sussex, United Kingdom * ''The Breach'', Great South Bay in the State of New York People * Breach (DJ), an Electronic/House music act * Miroslav ...
for unknown reasons. Both species are listed as vulnerable by the
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
.
Anthropogenic Anthropogenic ("human" + "generating") is an adjective that may refer to: * Anthropogeny, the study of the origins of humanity Counterintuitively, anthropogenic may also refer to things that have been generated by humans, as follows: * Human i ...
threats include
pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, th ...
, entanglement in
fishing net A fishing net is a Net (device), net used for fishing. Nets are devices made from fibers woven in a grid-like structure. Some fishing nets are also called fish traps, for example #Fyke nets, fyke nets. Fishing nets are usually meshes formed by ...
s, and direct harvesting of their gill rakers for use in
Chinese medicine Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logical mechanism of action ...
. Their slow reproductive rate exacerbates these threats. They are protected in
international waters The terms international waters or transboundary waters apply where any of the following types of bodies of water (or their drainage basins) transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed region ...
by the Convention on Migratory Species of Wild Animals, but are more vulnerable closer to shore. Areas where mantas congregate are popular with tourists. Only a few public aquariums are large enough to house them.


Etymology

The name "manta" is Portuguese and
Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...
for mantle (cloak or blanket), a type of blanket-shaped trap traditionally used to catch rays. Mantas are known as "devilfish" because of their horn-shaped cephalic fins, which are imagined to give them an "evil" appearance.


Taxonomy

Manta rays are members of the order Myliobatiformes which consists of
stingray Stingrays are a group of sea rays, which are cartilaginous fish related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae ...
s and their relatives. The genus ''Manta'' is part of the eagle ray
family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Myliobatidae, where it is grouped in the subfamily Mobulinae along with the smaller ''
Mobula ''Mobula'' is a genus of rays in the family Mobulidae that is found worldwide in tropical and warm, temperate seas. Some authorities consider this to be a subfamily of the Myliobatidae (eagle rays). Their appearance is similar to that of manta ...
'' devil rays. In 2018, an analysis of DNA, and to a lesser degree, morphology, found that ''Mobula'' was
paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...
with respect to the manta rays; that is, the members of the genus ''Manta'' are closer related to some members of genus ''Mobula'' than them to other ''Mobula'', and they recommended treating ''Manta'' as a
junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linn ...
of ''Mobula''. Mantas evolved from bottom-dwelling stingrays, eventually developing more wing-like pectoral fins. ''M. birostris'' still has a
vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...
remnant of a sting barb in the form of a
caudal Caudal may refer to: Anatomy * Caudal (anatomical term) (from Latin ''cauda''; tail), used to describe how close something is to the trailing end of an organism * Caudal artery, the portion of the dorsal aorta of a vertebrate that passes into the ...
spine. The mouths of most rays lie on the underside of the head, while in mantas, they are right at the front. The edges of the jaws line up while in devil rays, the lower jaw shifts back when the mouth closes. Manta rays and devil rays are the only ray species that have evolved into filter feeders. Manta rays have dorsal slit-like spiracles, traits which they share with the
devil fish The devil fish or giant devil ray (''Mobula mobular'') is a species of ray in the family Mobulidae. It is currently listed as endangered, mostly due to bycatch mortality in unrelated fisheries. Description The devil fish is larger than its clo ...
and Chilean devil ray.


Species

The scientific naming of mantas has had a convoluted history, during which several names were used for both the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
(''Ceratoptera'', ''Brachioptilon'', ''Daemomanta'', and ''Diabolicthys'') and
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
(such as ''vampyrus'', ''americana'', ''johnii'', and ''hamiltoni''). All were eventually treated as
synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are al ...
s of the single species ''Manta birostris''. Check genus and type "Manta" in search box. The genus name ''Manta'' was first published in 1829 by Dr Edward Nathaniel Bancroft of Jamaica.; see E.N. Bancroft ''On the fish known in Jamaica as the sea-devil'', 1829 The specific name '' birostris'' is ascribed to
Johann Julius Walbaum Johann Julius Walbaum (30 June 1724 – 21 August 1799) was a German physician, naturalist and fauna taxonomist. Works As an ichthyologist, he was the first to describe many previously unknown fish species from remote parts of the globe, suc ...
(1792) by some authorities and to Johann August Donndorff (1798) by others. The specific name ''alfredi'' was first used by Australian zoologist
Gerard Krefft Johann Ludwig (Louis) Gerard Krefft (17 February 1830 – 19 February 1881), a talented artist and draughtsman, and the Curator of the Australian Museum for 13 years (1861-1874), was one of Australia's first and most influential zoologists an ...
, who named the manta after Prince Alfred. A 2009 study analyzed the differences in morphology, including color, meristic variation, spine,
dermal denticle A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as ...
s (tooth-like scales), and teeth of different populations. Two distinct species emerged: the smaller '' M. alfredi'' found in the
Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...
and
tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...
East Atlantic, and the larger '' M. birostris'' found throughout tropical,
subtropical The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north a ...
and warm
temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...
oceans. The former is more coastal, while the latter is more ocean-going and migratory. A 2010 study on mantas around
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...
confirmed the morphological and genetic differences between ''M. birostris'' and ''M. alfredi''. A third possible species, preliminarily called ''Manta ''sp. cf. ''birostris'', reaches at least in width, and inhabits the tropical West Atlantic, including the Caribbean.


Fossil record

While some small teeth have been found, few fossilized skeletons of manta rays have been discovered. Their cartilaginous skeletons do not preserve well, as they lack the
calcification Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature M ...
of the
bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartil ...
. Only three sedimentary beds bearing manta ray fossils are known, one from the
Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...
in
South Carolina )''Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no) , anthem = " Carolina";" South Carolina On My Mind" , Former = Province of South Carolina , seat = Columbia , LargestCity = Charleston , LargestMetro = ...
and two from the
Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
and
Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58North Carolina North Carolina () is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. The state is the List of U.S. states and territories by area, 28th largest and List of states and territories of the United ...
. Click on "Age range and collections". '' M. hynei'' is a fossil species dating to
Early Pliocene Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * ...
North America. Remains of an extinct species have been found in the
Chandler Bridge Formation The Chandler Bridge Formation is a Formation (geology), geologic formation in South Carolina. It preserves fossils dating back to the Chattian (Late Oligocene) of the Paleogene Period (geology), period, corresponding to the Arikareean in the Nort ...
of South Carolina. These were originally described as ''Manta fragilis'', but were later reclassified as '' Paramobula fragilis''.


Biology


Characteristics

Manta rays have broad heads, triangular
pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...
s, and horn-shaped cephalic fins located on both sides of their mouths. They have horizontally flattened bodies with eyes on the sides of their heads behind the cephalic fins, and gill slits on their
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 roots, describe something in its standard anatomical position. This position prov ...
surfaces. Their tails lack skeletal support and are shorter than their disc-like bodies. The
dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...
s are small and at the base of the tail. Mantas can reach . In both species, the width is about 2.2 times the length of the body; ''M. birostris'' reaches at least in width, while ''M. alfredi'' reaches about . Their skin is covered in
mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It ...
. Mantas normally have a "chevron" coloration. They are typically black or dark on top with pale markings on their "shoulders". Underneath, they are usually white or pale with distinctive dark markings by which individual mantas can be recognized, as well as some shading. Individuals can also vary from mostly black (
melanism The term melanism refers to black pigment and is derived from the gr, μελανός. Melanism is the increased development of the dark-colored pigment melanin in the skin or hair. Pseudomelanism, also called abundism, is another variant of ...
) to mostly white (
leucism Leucism () is a wide variety of conditions that result in the partial loss of pigmentation in an animal—causing white, pale, or patchy coloration of the skin, hair, feathers, scales, or cuticles, but not the eyes. It is occasionally spelled ...
). These color morphs appear to be products of
neutral mutation Neutral mutations are changes in DNA sequence that are neither beneficial nor detrimental to the ability of an organism to survive and reproduce. In population genetics, mutations in which natural selection does not affect the spread of the mutatio ...
s and have no effects on fitness. A pink manta ray has been observed in Australia's
Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, A ...
and scientists believe this could be due to a
genetic mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...
causing
erythrism Erythrism or erythrochroism refers to an unusual reddish pigmentation of an animal's hair, skin, feathers, or eggshells. Causes of erythrism include: * Genetic mutations which cause an absence of a normal pigment and/or excessive production of ot ...
. The fish, spotted near Lady Elliot Island, is the world's only known pink manta ray. The two species of manta differ in color patterns, dermal denticles, and dentition. ''M. birostris'' has more angular shoulder markings, ventral dark spots on the abdominal region,
charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, ...
-coloured ventral outlines on the pectoral fins, and a dark colored mouth. The shoulder markings of ''M. alfredi'' are more rounded, while its ventral spots are located near the posterior end and between the gill slits, and the mouth is white or pale colored. The denticles have multiple
cusp A cusp is the most pointed end of a curve. It often refers to cusp (anatomy), a pointed structure on a tooth. Cusp or CUSP may also refer to: Mathematics * Cusp (singularity), a singular point of a curve * Cusp catastrophe, a branch of bifurc ...
s and overlap in ''M. birostris'', while those of ''M. alfredi'' are evenly spaced and lack cusps. Both species have small, square-shaped teeth on the lower jaw, but ''M. birostris'' also has enlarged teeth on the upper jaw. Unlike ''M. alfredi'', ''M. birostris'' has a caudal spine near its dorsal fin. Mantas move through the water by the wing-like movements of their pectoral fins. Their large mouths are rectangular, and face forward. The spiracles typical of rays are vestigial and concealed by small flaps of skin, and mantas must keep swimming with their mouths open to keep oxygenated water passing over their gills. The cephalic fins are usually spiraled but flatten during foraging. The fish's
gill arches Branchial arches, or gill arches, are a series of bony "loops" present in fish, which support the gills. As gills are the primitive condition of vertebrates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arc ...
have pallets of pinkish-brown spongy tissue that collect food particles. Mantas track down prey using visual and
olfactory The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, ...
senses. They have one of the highest brain-to-body mass ratios and the largest brain size of all fish. Their brains have
retia mirabilia A rete mirabile ( Latin for "wonderful net"; plural retia mirabilia) is a complex of arteries and veins lying very close to each other, found in some vertebrates, mainly warm-blooded ones. The rete mirabile utilizes countercurrent blood flow with ...
which may serve to keep them warm. ''M. alfredi'' has been shown to dive to depths over , while the Chilean devil ray, which has a similar structure, dives to nearly .


Lifecycle

Mating takes place at different times of the year in different parts of the manta's range. Courtship is difficult to observe in this fast-swimming fish, although mating "trains" with multiple individuals swimming closely behind each other are sometimes seen in shallow water. The mating sequence may be triggered by a
full moon The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (when the ecliptic longitudes of the Sun and Moon differ by 180°). This mea ...
and seems to be initiated by a male following closely behind a female while she travels at around . He makes repeated efforts to grasp her pectoral fin with his mouth, which may take 20 to 30 minutes. Once he has a tight grip, he turns upside-down and presses his ventral side against hers. He then inserts one of his
clasper In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating. Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's c ...
s into her
cloaca In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, ...
, where it remains for 60–90 seconds. The claspers form a tube and a
siphon A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...
propels
semen Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Sem ...
from the genital papilla into the oviduct. The male continues to grip the female's pectoral fin with his teeth for a further few minutes as both continue to swim, often followed by up to 20 other males. The pair then parts, the female being left with scars of her fin. The fertilized eggs develop within the female's oviduct. At first, they are enclosed in an egg case while the developing
embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
s absorb the yolk. After hatching, the pups remain in the oviduct and receive additional nutrition from milky secretions. With no
umbilical cord In placental mammals, the umbilical cord (also called the navel string, birth cord or ''funiculus umbilicalis'') is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord is physiologi ...
or
placenta The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mate ...
, the unborn pup relies on
buccal pumping Buccal pumping is "breathing with one's cheeks": a method of ventilation used in respiration in which the animal moves the floor of its mouth in a rhythmic manner that is externally apparent.Brainerd, E. L. (1999). New perspectives on the evolutio ...
to obtain oxygen. Brood size is usually one or occasionally two. The
gestation period In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once ...
is thought to be 12–13 months. When fully developed, the pup resembles a miniature adult and is expelled from the oviduct with no further parental care. In wild populations, an interval of two years between births may be normal, but a few individuals become pregnant in consecutive years, demonstrating an annual ovulatory cycle. The Okinawa Churaumi Aquarium has had some success in breeding ''M. alfredi'', with one female giving birth in three successive years. In one of these pregnancies, the gestation period was 372 days and at birth the pup had a width of and weight of . In Indonesia, ''M. birostris'' males appear to mature at , while female mature around . In the
Maldives Maldives (, ; dv, ދިވެހިރާއްޖެ, translit=Dhivehi Raajje, ), officially the Republic of Maldives ( dv, ދިވެހިރާއްޖޭގެ ޖުމްހޫރިއްޔާ, translit=Dhivehi Raajjeyge Jumhooriyyaa, label=none, ), is an archipelag ...
, males of ''M. alfredi'' mature at a width of , while females mature at . In
Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
, ''M. alfredi'' matures at a width of for males and for females. Female mantas appear to mature at 8–10 years. Manta rays may live as long as 50 years.


Behavior and ecology

Swimming behavior in mantas differs across habitats: when travelling over deep water, they swim at a constant rate in a straight line, while further inshore, they usually bask or swim idly around. Mantas may travel alone or in groups up to 50. They may associate with other fish species, as well as sea birds and
marine mammal Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their ...
s. Mantas sometimes
breach Breach, Breached, or The Breach may refer to: Places * Breach, Kent, United Kingdom * Breach, West Sussex, United Kingdom * ''The Breach'', Great South Bay in the State of New York People * Breach (DJ), an Electronic/House music act * Miroslav ...
or leap out of the water. Individuals in a group may make aerial jumps in succession. Mantas may leap forward and re-enters head first, tail first or make
somersault A somersault (also ''flip'', ''heli'', and in gymnastics ''salto'') is an acrobatic exercise in which a person's body rotates 360° around a horizontal axis with the feet passing over the head. A somersault can be performed forwards, backwards ...
s. The reason for breaching is not known; possible explanations include communication, or the removal of
parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...
s and
remora The remora (), sometimes called suckerfish, is any of a family (Echeneidae) of ray-finned fish in the order Carangiformes. Depending on species, they grow to long. Their distinctive first dorsal fins take the form of a modified oval, sucker-li ...
s (suckerfish). Mantas visit
cleaning station A cleaning station is a location where aquatic life congregate to be cleaned by smaller creatures. Such stations exist in both freshwater and marine environments, and are used by animals including fish, sea turtles and hippos, referred to as cli ...
s on
coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...
s for the removal of external parasites. The ray adopts a near-stationary position close to the coral surface for several minutes while the cleaner fish feed. Such visits most frequently occur when the tide is high. Individual mantas may revisit the same cleaning station or feeding area repeatedly and appear to have
cognitive maps A cognitive map is a type of mental representation which serves an individual to acquire, code, store, recall, and decode information about the relative locations and attributes of phenomena in their everyday or metaphorical spatial environment. T ...
of their environment. In addition, it has been confirmed that reef manta rays form a community with a specific individual and act together. Mantas may be preyed upon by large
shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachi ...
s,
orca The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus '' Orcinus'' and is recognizable by its black-and-white ...
s and false killer whales. They may also harbor parasitic
copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (inhabiting sea waters), some are benthic (living on the ocean floor), a number of species have ...
s. Mantas can remove internal parasites by sticking their intestines up to out of their cloaca and squeezing them out, often while defecating. Remoras adhere themselves onto mantas for transportation and use their mouths as shelter. Though they may clean them of parasites, remoras can also damage the manta's gills and skin, and increase its swimming load. In 2016, scientists published a study in which manta rays were shown to exhibit behavior associated with
self-awareness In philosophy of self, self-awareness is the experience of one's own personality or individuality. It is not to be confused with consciousness in the sense of qualia. While consciousness is being aware of one's environment and body and lifest ...
. In a modified
mirror test The mirror test—sometimes called the mark test, mirror self-recognition (MSR) test, red spot technique, or rouge test—is a behavioral technique developed in 1970 by American psychologist Gordon Gallup Jr. as an attempt to determine whether an ...
, the individuals engaged in contingency checking and unusual self-directed behavior.


Feeding

Manta rays are
filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...
s as well as macropredators. On the surface, they consume large quantities of
zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
in the form of
shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are ref ...
,
krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consi ...
, and
planktonic Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cruc ...
crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all th ...
s. In deeper depths, mantas consume small to medium-sized fish. Foraging mantas flatten their cephalic fins to channel food into their mouths. During filter feeding, small particles are collected by the tissue between the gill arches. The standard method of feeding for a lone manta is simply swimming horizontally, turning 180 degrees to feed in the other direction. Up and down movements, sideways tilting and 360 degree somersaults are also observed. Mantas engage in a number of group feeding behaviors. An individual may "piggy-back" on a larger, horizontally feeding individual, placing itself over its back. "Chain-feeding" involves them aligning back-to-front and swimming horizontally. Chain-feeding mantas may create a circle, with the lead individual meeting up with the stragglers. More individuals may join, creating a "cyclone" of mantas spiraling upwards. With a diameter of , these cyclones consist of up to 150 mantas and last up to an hour. Studies have shown that around 27% of the diet of ''M. birostris'' is from the surface, while around 73% is at deeper depths. Mantas may forage on the ocean floor with the cephalic fins splayed apart. During filter feeding, the gills may get clogged up, forcing mantas to cough and create a cloud of gill waste. The rays commonly do this above cleaning stations, providing a feast for the cleaner fish. Mantas defecate dark red fecal matter which is often mistaken for blood.


Distribution and habitat

Mantas are found in tropical and subtropical waters in all the world's major oceans, and also venture into temperate seas. The furthest from 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 also ...
they have been recorded is
North Carolina North Carolina () is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. The state is the List of U.S. states and territories by area, 28th largest and List of states and territories of the United ...
in the United States (31°N) and the
North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-larges ...
of
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
(36°S). They prefer water temperatures above and ''M. alfredi'' is predominantly found in tropical areas. Both species are
pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...
. ''M. birostris'' lives mostly in the open ocean, travelling with the currents and migrating to areas where upwellings of nutrient-rich water increase prey concentrations. Fish that have been fitted with radio transmitters have traveled as far as from where they were caught, and descended to depths of at least . ''M. alfredi'' is a more resident and coastal species. Seasonal migrations do occur, but they are shorter than those of ''M. birostris''. Mantas are common around coasts from spring to fall, but travel further offshore during the winter. They keep close to the surface and in shallow water in daytime, while at night they swim at greater depths.


Conservation issues


Threats

The greatest threat to manta rays is
overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in t ...
. ''M. birostris'' is not evenly distributed over the oceans, but is concentrated in areas that provide the food resources it requires, while ''M. alfredi'' is even more localized. Their distributions are thus fragmented, with little evidence of intermingling of subpopulations. Because of their long lifespans and low reproductive rate, overfishing can severely reduce local populations with little likelihood that individuals from elsewhere will replace them. Both
commercial Commercial may refer to: * a dose of advertising conveyed through media (such as - for example - radio or television) ** Radio advertisement ** Television advertisement * (adjective for:) commerce, a system of voluntary exchange of products and s ...
and
artisanal An artisan (from french: artisan, it, artigiano) is a skilled craft worker who makes or creates material objects partly or entirely by hand. These objects may be functional or strictly decorative, for example furniture, decorative art, ...
fisheries have targeted mantas for their meat and products. They are typically caught with nets, trawls, and harpoons. Mantas were once captured by fisheries in California and Australia for their liver oil and skin; the latter made into
abrasive An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflec ...
s. Their flesh is edible and is consumed in some countries, but is unattractive compared to other fish. Demand for their gill rakers, the cartilaginous structures protecting the gills, has recently entered
Chinese medicine Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logical mechanism of action ...
. To fill the growing demand in Asia for gill rakers, targeted fisheries have developed in the Philippines, Indonesia, Mozambique, Madagascar, India, Pakistan, Sri Lanka, Brazil, and Tanzania. Each year, thousands of manta rays, primarily ''M. birostris'', are caught and killed purely for their gill rakers. A fisheries study in Sri Lanka and India estimated that over 1000 were being sold in the country's fish markets each year. By comparison, ''M. birostris'' populations at most of the key aggregation sites around the world are estimated to have significantly fewer than 1000 individuals. Targeted fisheries for manta rays in the
Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja C ...
, the west coast of Mexico, India, Sri Lanka, Indonesia, and the Philippines have reduced populations in these areas dramatically. Manta rays are subject to other human impacts. Because mantas must swim constantly to flush oxygen-rich water over their gills, they are vulnerable to entanglement and subsequent
suffocation Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects primarily the tissues and organs. There are many circumstances that can ...
. Mantas cannot swim backwards, and because of their protruding cephalic fins, are prone to entanglement in fishing lines, nets, ghost nets, and even loose mooring lines. When snared, mantas often attempt to free themselves by somersaulting, tangling themselves further. Loose, trailing line can wrap around and cut its way into its flesh, resulting in irreversible injury. Similarly, mantas become entangled in gill nets designed for smaller fish. Some mantas are injured by collision with boats, especially in areas where they congregate and are easily observed. Other threats or factors that may affect manta numbers are
climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
, tourism, pollution from
oil spill An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into t ...
s, and the ingestion of
microplastics Microplastics are fragments of any type of plastic less than in length, according to the U.S. National Oceanic and Atmospheric Administration (NOAA) and the European Chemicals Agency. They cause pollution by entering natural ecosystems from a v ...
.


Status

The
IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
listed the reef manta as vulnerable in 2019 and the giant manta as
endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...
in 2020. In 2011, mantas became strictly protected in international waters because of their inclusion in the Convention on Migratory Species of Wild Animals. The CMS is an international treaty organization concerned with conserving migratory species and habitats on a global scale. Although individual nations were already protecting manta rays, the fish often migrate through unregulated waters, putting them at increased risk from overfishing. The Manta Trust is a UK-based charity dedicated to research and conservation efforts for manta rays. The organization's website is also an information resource for manta conservation and biology. In 2009, Hawaii became the first of the United States to introduce a ban on the killing or capturing of manta rays. Previously, no fishery for mantas existed in the state but migratory fish that pass the islands are now protected. In 2010, Ecuador introduced a law prohibiting all fishing for manta and other rays, their retention as bycatch and their sale.


Relation with humans

The ancient
Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...
vian Moche people worshipped the sea and its animals. Their art often depicts manta rays. Historically, mantas were feared for their size and power. Sailors believed that they were dangerous to humans and could pull ships out to sea by the anchor. This attitude changed around 1976, when divers around the Gulf of California found them to be placid and that they could interact with the animals. Several divers photographed themselves with mantas, including ''
Jaws Jaws or Jaw may refer to: Anatomy * Jaw, an opposable articulated structure at the entrance of the mouth ** Mandible, the lower jaw Arts, entertainment, and media * Jaws (James Bond), a character in ''The Spy Who Loved Me'' and ''Moonraker'' * ...
'' author
Peter Benchley Peter Bradford Benchley (May 8, 1940 – February 11, 2006) was an American author, screenwriter, and ocean activist. He is known for his bestselling novel '' Jaws'' and co-wrote its film adaptation with Carl Gottlieb. Several more of his works ...
.


Aquariums

The Okinawa Ocean Expo Aquarium acquired mantas in 1981 which survived for four days. In addition, at the Okinawa Churaumi Aquarium, a male manta ray, which started captivity in 1992 at its predecessor, the Okinawa Ocean Expo Aquarium, was recorded to have lived for approximately 23 years. The Okinawa Churaumi Aquarium houses manta rays in the "Kuroshio Sea" tank, one of the largest aquarium tanks in the world. The first manta ray birth in captivity took place there in 2007. Although this pup did not survive, the aquarium has since had the birth of four more manta rays in 2008, 2009, 2010 and 2011. However, although Manta became pregnant in 2012, she was stillborn. In 2013, she became pregnant, but her mother, manta ray, died and the pup that was taken out died. There are currently four mantas spending time at the
Georgia Aquarium Georgia Aquarium is a public aquarium in Atlanta, Georgia, United States. It exhibits hundreds of species and thousands of animals across its seven major galleries, all of which reside in more than of water. It was the largest aquarium in the wo ...
. One notable individual is "Nandi", a manta ray which was accidentally caught in shark nets off
Durban Durban ( ) ( zu, eThekwini, from meaning 'the port' also called zu, eZibubulungwini for the mountain range that terminates in the area), nicknamed ''Durbs'',Ishani ChettyCity nicknames in SA and across the worldArticle on ''news24.com'' from ...
, South Africa, in 2007. Rehabilitated and outgrowing her aquarium at
uShaka Marine World uShaka Marine World is a theme park that opened on 30 April 2004 in Durban, KwaZulu-Natal, South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded ...
, Nandi was moved to the larger Georgia Aquarium in August 2008, where she resides in its 23,848 m3 (6,300,000 US gal) "Ocean Voyager" exhibit. A second manta ray, "Tallulah", joined that aquarium's collection in September 2009 and a third was added in 2010. The Atlantis resort on
Paradise Island Paradise Island is an island in The Bahamas formerly known as Hog Island. The island, with an area of (2.8 km2/1.1 sq mi), is located just off the shore of the city of Nassau, which is itself located on the northern edge of the island of ...
, Bahamas, hosted a manta named "Zeus" that was used as a research subject for three years until it was released in 2008.


Tourism

Manta ray tourism is estimated to generate over US$73 million per year and brings US$140 million per year to local economies. The majority of global revenues come from ten countries: Japan, Indonesia, the
Maldives Maldives (, ; dv, ދިވެހިރާއްޖެ, translit=Dhivehi Raajje, ), officially the Republic of Maldives ( dv, ދިވެހިރާއްޖޭގެ ޖުމްހޫރިއްޔާ, translit=Dhivehi Raajjeyge Jumhooriyyaa, label=none, ), is an archipelag ...
, Mozambique, Thailand, Australia, Mexico, United States,
Federated States of Micronesia The Federated States of Micronesia (; abbreviated FSM) is an island country in Oceania. It consists of four states from west to east, Yap, Chuuk, Pohnpei and Kosraethat are spread across the western Pacific. Together, the states compr ...
and
Palau Palau,, officially the Republic of Palau and historically ''Belau'', ''Palaos'' or ''Pelew'', is an island country and microstate in the western Pacific. The nation has approximately 340 islands and connects the western chain of the ...
. Divers may get a chance to watch mantas visiting cleaning stations and night dives enable viewers to see mantas feeding on plankton attracted by the lights. Ray tourism benefits locals and visitors by raising awareness of natural resource management and educating them about the animals. It can also provide funds for research and conservation. Constant unregulated interactions with tourists can negatively affect the fish by disrupting ecological relationships and increasing disease transmission. In 2014, Indonesia banned fishing and export targeting the species, as manta ray tourism is more economically beneficial than allowing the fish to be killed. A dead manta is worth $40 to $500, while the economic impact of tourism at a popular dive site can be $1 million per manta over its life. Indonesia has 5.8 million km2 (2.2 million mi2) of ocean, and this is now the world's largest sanctuary for manta rays.


See also

* List of threatened rays *
Manta Matcher Manta Matcher is a global online database for manta rays. It is one of the Wildbook Web applications developed by Wild Me, a 501(c)(3) not-for-profit organization in the United States, and was created in partnership with Andrea Marshall of the M ...


References


External links


Maldives Manta Rays: VIDEOMicrodocs



Manta Ray videos and news stories from the BBC including footage of the possible new species
* *
Diving with Mantas at the Azores

Meet the Maldivian Mantas
'' Manta Trust''.
Manta Matcher – The Wildbook for Manta Rays

Japans giant manta ray, Okinawa world’s first to exhibit
{{DEFAULTSORT:Manta ray Myliobatidae Cosmopolitan fish Articles containing video clips Extant Miocene first appearances Aquitanian genus first appearances Taxa named by Edward Nathaniel Bancroft