Amphibians

Lithobates catesbeianus

The American bullfrog is the largest true frog native to North America, named for its deep, resonant call that resembles a bull's bellow. Highly adaptable and voracious, it will eat almost any animal small enough to fit in its mouth, from insects to other frogs, and has become one of the world's most widely introduced invasive amphibians outside its native range.

Ambystoma mexicanum

The axolotl is a remarkable salamander from a single lake system in Mexico that never fully undergoes metamorphosis, instead retaining its larval, gilled form and living its entire life underwater. This permanent juvenile state, called neoteny, along with its extraordinary ability to regrow lost limbs, organs, and even parts of its brain, has made it one of the most studied animals in modern regenerative biology research.

Phyllobates terribilis

The golden poison frog is widely regarded as the most toxic animal on Earth by weight, native to a small stretch of Colombian rainforest.

Ambystoma tigrinum

The tiger salamander is one of the largest land-dwelling salamanders in North America, named for the yellow or olive blotches and stripes marking its dark body. Most of its life is spent hidden underground in burrows, either ones it digs itself or ones abandoned by other animals, only emerging at night or during its brief breeding season.