Peruvian Poison Frog

The Peruvian Poison Frog, Hyloxalus argyrogaster, is a species of frog in the family Dendrobatidae. It is endemic to Peru. Its sister species is thought to be Hyloxalus fallax. It is the fourth-most poisonous of its genus, and is coloured so to stand out from its natural habitat of leaves on the forest floor.

Poison
The Peruvian Poison Frog, like all poison dart frogs, contains an alkaloid neurotoxin in its skin. This poison destroys nerve cells and sends powerful impulses, resulting in extreme pain. However, due to its minute size, the Peruvian poison frog only holds a small amount of poison; on average, a wild Peruvian poison frog will contain around one milligram of poison, enough to cause severe pain in humans, but not enough to kill a human. Its poison is enough, however, to protect it from most mammal predators, which have less tolerance to the toxin than cold-blooded animals. If attacked by snakes or other resistant animals, H. argyrogaster will usually rely on its speed and agility to escape from the danger.

Description
The Peruvian Poison Frog is one of the smallest poison-dart frog species known; males average 1.4-1.65 cm in length from snout to vent; as with all frogs, the females are larger, up to 2 cm long. Because it contains very little poison, the Peruvian poison frog is cryptically coloured. Common color morphs include wood brown, beige, olive green, or cream-coloured to blend in with the leaf litter. H. argyrogaster is slender in build, but with unusually thick legs for a poison dart frog; these allow it to jump farther in order to escape predators. The frog's slender build also allows it to wriggle under leaves in the event that it must take cover quickly.

H. argyrogaster is the only poison dart frog to have a visible iris. Because of the habitat of the Peruvian poison frog (in the leaf litter), oval-shaped pupils allow the frogs to see in all directions to detect the predators that abound in the leaf litter. Most poison-dart frogs live in the canopy or the understory, which has fewer predators and thus do not need to see in all directions. While most poison dart frog species can warn predators off with its their colours and body language, the Peruvian poison frog has less toxin and must be able to swiftly evade any attackers.