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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 only 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 foun ...
from the rainforests of
Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...
. The golden poison frog has become endangered due to
habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...
within its naturally limited range. Despite its small size, this frog is considered to be the most poisonous extant animal species 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 (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...
.


Distribution and habitat

The golden poison frog is
endemic Endemism is the state of a species being found only 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 foun ...
to humid forests of the Pacific coast of
Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...
in the Cauca and Valle del Cauca Departments in the Chocó Rainforest. The optimal habitat of this species is the
rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...
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 or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...
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 in biology, advertising by an animal, whether terrestrial or marine, to potential predation, predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the pr ...
(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'' and '' Paratrechina'', but many kinds of insects and other small
invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...
s are eaten. 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. There are two forms of reproduction: Asexual reproduction, asexual and Sexual ...
, 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 Plant litter (also leaf litter, tree litter, soil litter, litterfall, or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that has fallen to the ground. This detritus or dead organic material and its constituen ...
. 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 (biology), family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the Tropics, tropical Americas, with several species found in the American subtropics and on ...
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 one of the most poisonous animals on the planet; these frogs produce deadly alkaloid
batrachotoxin Batrachotoxin (BTX) is an extremely potent cardiotoxic and neurotoxic steroidal alkaloid found in certain species of beetles, birds, and frogs. The name is from the Greek word . Structurally-related chemical compounds are often referred to collec ...
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 primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...
(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 wil ...
''), a few
birds Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
from
Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...
, and four Papuan beetles of the genus '' Choresine'' 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 (biology), cell's cell membrane, membrane. They belong to the Cation channel superfamily, superfamily of cation channels. Classific ...
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 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. Classification They are classified into 2 types: Function In e ...
of nerve cells, leaving the
muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...
s in an inactive state of contraction. This can lead to paralysis, heart fibrillation,
heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...
, 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 spelled kilogramme) is the base unit of mass in the International System of Units (SI), equal to one thousand grams. It has the unit symbol kg. The word "kilogram" is formed from the combination of the metric prefix kilo- (m ...
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 A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...
,
salivation Saliva (commonly referred as spit or drool) 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 DN ...
,
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 ...
,
dyspnoea Shortness of breath (SOB), 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 discomfort that c ...
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 Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...
s or other
arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...
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'', '' ...
''. Scientists have suggested the crucial prey item may be a small
beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
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 Cofan or Cofán may refer to: * Cofán people, an ethnic group of Ecuador and Colombia * Cofán language, their language See also * Kofan (disambiguation) * Cofana ''Cofana'' is a genus of leafhoppers belonging to the family Cicadellidae. ...
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 (; 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 are not connected to other water bodies. An animal enclosur ...
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 The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
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