Peruvian Poison Frog

The Peruvian Poison Frog (Hyloxalus argyrogaster) is a species of poison dart frog in the Hyloxalus genus. Despite having cryptic coloration, it is quite toxic; its poison is only slightly weaker than that of H. subpunctatus, making it the 16th most toxic of the poison dart frog species. The Peruvian Poison Frog's natural habitat consists of subtropical or tropical moist lowland forests, subtropical or tropical moist montanes, and rivers.

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. Certain predators, such as snakes, are not affected by this poison and prey on all but the most toxic of poison-dart frogs. The Peruvian poison frog is a frequent and easy target for such snakes; as a result it is cryptically coloured. Its poison is enough, however, to protect it from most mammal predators, which have less tolerance to the toxin than cold-blooded animals.

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.

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