Poison dart frog

Poison dart frog is the common name of a group of frogs in the family Dendrobatidae. They are native to Central and South America. 

Unlike many frogs, poison dart frogs are active during the day. They often have brightly-coloured bodies, which act as warning colouration. All dendrobatids are at least somewhat toxic. In the wild, frogs of different species and in different places may have very different levels of toxicity. Many species are critically endangered. 

Poison dart frogs are poisonous because they eat ants and other small insects that have toxins in their bodies. If an animal eats the frog, it will become very sick. 

 Toxicity 
Many poison dart frogs secrete alkaloid toxins through their skin. Alkaloids in the skin glands of poison frogs serve as a chemical defense against predation. This lets them be active alongside potential predators during the day. About 28 structural classes of alkaloids are known in poison frogs. The most toxic species of poison dart frog is Phyllobates terribilis.

Poison dart frogs do not make their own poisons, but keep (sequester) the chemicals from arthropod prey, such as ants, centipedes and mites. This is the diet-toxicity hypothesis.Darst C. et al 2005. Evolution of dietary specialization and chemical defense in poison frogs (Dendrobatidate): a comparative analysis. The American Natural 165: 56–69. Because of this, captive-bred animals do not have significant levels of toxins: they are reared on diets that do not have the alkaloids used by wild populations. Nonetheless, the captive-bred frogs can store up alkaloids if their diet has alkaloids. 

Most wild species are not lethal to their predators, but rather taste foul enough that the predators release the frogs. Despite this, some predators can withstand the toxins used by some poison dart frogs. One is the snake Leimadophis epinephelus, which has developed immunity to the poison.

Taxonomy
Dart frogs are the focus of many studies. Their scientific names may sometimes change. Family Dendrobatidae was revised in 2006 and now has 12 genera, with about 170 species.

Color morphs
Some poison dart frog species include a number of color morphs that evolved as recently as 6,000 years ago. 

Predation does affect the evolution of polymorphism, for example, in O. granulifera. Sexual selection has contributed to differentiation among the Bocas del Toro populations of Oophaga pumilio.

References

Grant, Taran. "Poison dart frog." World Book Advanced. World Book, 2013.Web. 10 Jan. 2013.

 Other websites 

Dyeing Poison Frog. ARKive, n.d. Web. 17 Jan. 2013. <http://www.arkive.org/ >.


Category:Venomous animals
Category:Frogs of South America