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The golden poison frog (''Phyllobates terribilis''), also known as the golden dart frog or golden poison arrow frog, is a
poison dart frog Poison dart frog (also known as dart-poison frog, poison frog or formerly known as poison arrow frog) is the common name of a group of frogs in the family Dendrobatidae which are native to tropical Central and South America. These species are ...
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to the rainforests of
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 ...
. The golden poison frog has become endangered due to habitat destruction within its naturally limited range. Despite its small size, this frog is likely the most poisonous animal on the planet.


Taxonomy and etymology

The golden poison frog was described as ''Phyllobates terribilis'' in 1978 by herpetologists Charles W. Myers and Borys Malkin as well as biochemist John W. Daly; the species name ''terribilis'' is a reference to the deadly toxins present in the skin secretions of this species. Myers' research was based on hundreds of specimens collected on an expedition to the Quebrada Guangui and La Brea regions of the Colombian rainforest, and a breeding colony of 18 frogs established at the
American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...
.


Distribution and habitat

The golden poison frog is
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to humid forests of the Pacific coast of
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 ...
in the Cauca and Valle del Cauca Departments in the Chocó Rainforest. The optimal habitat of this species is the
rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...
with high rain rates (5 m or more per year), altitudes from sea level to 200 m elevation, temperatures of at least 26 °C, and relative humidity of 80–90%. It is known only from primary forest. The eggs are laid on the ground; the males transport the
tadpole A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found i ...
s to permanent pools. Its range is less than 5,000 square km; destruction of this habitat has contributed to ''P. terribilis'' becoming an endangered species.


Description

The golden poison frog is the largest species of the
poison dart frog Poison dart frog (also known as dart-poison frog, poison frog or formerly known as poison arrow frog) is the common name of a group of frogs in the family Dendrobatidae which are native to tropical Central and South America. These species are ...
family, and can reach a weight of nearly 30 grams with a length of 6 cm as adults. Females are typically larger than males. The adults are brightly colored, while juvenile frogs have mostly black bodies with two golden-yellow stripes along their backs. The black fades as they mature, and at around 18 weeks of age the frog is fully colored. The frog's color pattern is
aposematic Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...
(a coloration to warn predators of its toxicity). Despite their common name, golden poison frogs occur in four main color varieties or morphs:


Yellow

The yellow morph is the reason ''Phyllobates terribilis'' has the common name golden poison frog. These frogs can be pale yellow to deep, golden yellow in color. Yellow ''Phyllobates terribilis'' specimens are found in Quebrada Guangui, Colombia.


Mint green

The largest morph of ''Phyllobates terribilis'' exists in the La Brea and La Sirpa areas in Colombia; despite the name "mint green" these frogs can be metallic green, pale green, or white.


Orange

Orange examples of ''Phyllobates terribilis'' exist in Colombia, as well. They tend to be a metallic orange or yellow-orange in color, with varying intensity. They have been observed living near yellow specimens in Quebrada Guangui, Colombia, and it is unclear to what extent these represent an individual subpopulation or locality distinct from the yellow morph.


Orange blackfoot

The orange blackfoot morph is a captive bred line established by Tesoros de Colombia, a Colombian company that aims to reduce poaching of wild dart frogs by breeding rare species and flooding the pet trade with low cost animals to decrease the value of wild specimens to poachers. This morph is golden yellow to a deep orange. They have dark markings on their feet, throat, vent, and rump that range from distinct black to nearly absent or speckled grey. File:Golden Poison dart frog Phyllobates terribilis.jpg, Yellow File:Phyllobates terribilis 01.JPG, Mint green File:Golden Poison Dart Frog 1 (14412444930).jpg, Orange File:Phyllobates terribilis "orange blackfoot".jpg, Orange blackfoot


Ecology and behavior

The frog is normally diurnal; golden poison frogs live evenly spaced without forming larger congregations.


Diet

This species is an unspecialized ambush hunter; an adult frog can eat food items much larger in relation to its size than most other dendrobatids. The main natural sources of food of ''P. terribilis'' are the ants in the genera ''
Brachymyrmex ''Brachymyrmex'' is a genus in the ants subfamily Formicinae. The genus can be recognized by the combination of having nine antennal segments (fewer than most ants) and the petiole concealed by the gaster in dorsal view. They are sometimes called ...
'' and ''
Paratrechina ''Paratrechina'' is one of seven ant genera (alongside ''Euprenolepis, Nylanderia, Paraparatrechina, Prenolepis, Pseudolasius,'' and ''Zatania'') in the ''Prenolepis'' genus-group from the subfamily Formicinae (tribe Lasiini). Six species are ...
'', but many kinds of insects and other small
invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
s can be eaten, specifically
termite Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blattode ...
s and
beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s, which can easily be found on the rainforest floor. Tadpoles feed on algae, mosquito larvae, and other edible material that may be present in their environment.


Breeding

Males advertise to receptive females with a trilling call. Golden poison frogs are notable for demonstrating tactile courtship during
reproduction Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual or ...
, each partner stroking its mate's head, back, flanks, and cloacal areas prior to egg deposition. The eggs are fertilized externally. The golden poison frogs lay their eggs on the ground, hidden beneath leaf litter. Once the tadpoles emerge from their eggs, they stick themselves to the mucus on the backs of their parents. The adult frogs carry their young into the canopy, depositing them in the pools of water that accumulate in the centre of
bromeliad The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...
s and water-filled tree holes. The tadpoles feed on algae and mosquito larvae in their nursery.


Predators

Golden poison frogs are so toxic that adult frogs likely have few – if any – predators. The snake species '' Leimadophis epinephelus'' has shown resistance to several frog toxins including batrachotoxin, and has been observed to eat juvenile frogs without ill effects.


Toxicity

The golden poison frog is the most poisonous animal on the planet; these frogs produce deadly alkaloid
batrachotoxin Batrachotoxin (BTX) is an extremely potent cardio- and neurotoxic steroidal alkaloid found in certain species of beetles, birds, and frogs. The name is from the Greek word grc, βάτραχος, bátrachos, frog, label=none. Structurally-related ...
s in their skin glands as a defense against predators. To become poisoned a predator generally must attempt to consume the frog, although this species is so toxic that even touching an individual frog can be dangerous. This extraordinarily lethal poison is very rare. Batrachotoxin is found only in three poisonous frogs from
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 ...
(all genus ''
Phyllobates ''Phyllobates'' is a genus of poison dart frogs native to Central and South America, from Nicaragua to Colombia. There are 3 different Colombian species of ''Phyllobates'', considered highly toxic species due to the poison they contain in the w ...
''), a few
birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
from
Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...
, and four Papuan beetles of the genus ''
Choresine ''Choresine'' is a genus of beetles that belong to the Melyridae family. This genus of beetle is known to have high levels of batrachotoxins and is believed to be a possible toxin source for Pitohui and Blue-capped ifrit birds in New Guinea. Co ...
'' in the family
Melyridae Melyridae (common name: soft-winged flower beetles) are a family of beetles of the superfamily Cleroidea. Description Most are elongate-oval, soft-bodied beetles 10 mm long or less. Many are brightly patterned in black and brown, yellow, ...
. Batrachotoxin affects the
sodium channel Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels and can be classified according to the trigger that opens the channel ...
s of nerve cells. While it is unknown how the frog avoids poisoning itself, other species of poisonous frogs have been demonstrated to express a "toxin sponge" protein in blood plasma, internal organs, and muscle that binds and sequesters the toxin so as to prevent autointoxication.


Mechanism

Batrachotoxin binds to, and irreversibly opens, the
sodium channels Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels and can be classified according to the trigger that opens the channel ...
of nerve cells leaving the
muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
s in an inactive state of contraction, which can lead to paralysis, heart fibrillation,
heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
, and death. The average dose carried will vary between locations, and consequent local diet, but the average wild golden poison frog is generally estimated to contain about one
milligram The kilogram (also kilogramme) is the unit of mass in the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a kilo colloquially. ...
of poison, enough to kill between 10 and 20 humans, or up to two African bull elephants. Smaller doses have been shown to cause
seizures An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or neural oscillation, synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much o ...
,
salivation Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can be e ...
,
muscle contractions Muscle contraction is the activation of tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as w ...
,
dyspnoea Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing disc ...
and death in mice: the subcutaneous LD50 is just 0.2 µg / kg, although low doses such as 0.01 µg / kg and 0.02 µg / kg may be lethal. Myers ''et al.'' estimate that the lethal dose for humans is between 2.0 and 7.5 µg.


Synthesis

Golden poison frogs appear to rely on the consumption of small
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 or other
arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
s to synthesize batrachotoxin; frogs kept in captivity fed on commercially available feeder insects will eventually lose their toxicity, and frogs bred in captivity are considered non-toxic. It is not clear which prey species supplies the potent alkaloid that gives golden poison frogs their exceptionally high levels of toxicity, or whether the frogs modify another available toxin to produce a more efficient variant, as do some of the frogs from the genus ''
Dendrobates ''Dendrobates'' is a genus of poison dart frogs native to Central and South America. It once contained numerous species, but most originally placed in this genus have been split off into other genera such as ''Adelphobates'', '' Ameerega'', '' A ...
''. Scientists have suggested the crucial prey item may be a small
beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
from the family
Melyridae Melyridae (common name: soft-winged flower beetles) are a family of beetles of the superfamily Cleroidea. Description Most are elongate-oval, soft-bodied beetles 10 mm long or less. Many are brightly patterned in black and brown, yellow, ...
. At least one species of these beetles produces the same toxin found in golden poison frogs. Their relatives in Colombian rainforests could be the source of the batrachotoxins found in the highly toxic ''Phyllobates'' frogs of that region.


Use by indigenous people

Golden poison frogs are a very important frog to the local indigenous cultures, such as the Emberá and Cofán people in Colombia's rainforest. The frog is the main source of the poison in the darts used by the natives to hunt their food. The Emberá people carefully expose the frog to the heat of a fire, and the frog exudes small amounts of poisonous fluid. The tips of arrows and darts are soaked in the fluid, and remain deadly for two years or longer.


In captivity

The golden poison frog is a popular
vivarium A vivarium (Latin, literally for "place of life"; plural: ''vivaria'' or ''vivariums'') is an area, usually enclosed, for keeping and raising animals or plants for observation or research. Water-based vivaria may have open tops providing they a ...
subject due to its bright color and bold personality in captivity. Despite its dangerous toxicity in the wild, captive specimens raised without their natural food sources are non-toxic in captivity. Due to their small range in the wild, poaching for the pet trade formerly represented a serious threat to the survival of the species. Due to efforts of frog breeders like Tesoros de Colombia, captive bred frogs are now widely available for the pet trade. As these specimens are legal, non-toxic, healthier, and less expensive when compared to poached animals, the demand for illegally obtained wild caught specimens has decreased. Today, the IUCN estimates that the majority of golden poison frogs sold for the pet trade are legally produced from captive lines, and estimates the threat from collection for the pet trade to be small.


References


External links


The True Poison-Dart Frog: The Golden Poison Frog Phyllobates terribilisGolden Poison Dart Frog
at National Geographic {{Taxonbar, from=Q963997 Phyllobates Amphibians of Colombia Endemic fauna of Colombia Amphibians described in 1978 Taxa named by Charles W. Myers