The axolotl (Ambystoma mexicanum) is a fascinating little amphibian. This salamander, closely related to the much more normal-looking tiger salamander, is unfortunately labeled as "Critically Endangered" by the IUCN, due to destruction of its native habitat. The axolotl is endemic to two lakes in central Mexico, Lake Xochimilco (pronounced SHO-chan-ha-nay-shanay) and Lake Chalco. Lake Chalco, however, is no more, as it was drained by humans to avoid flooding. Lake Xochimilco, on the other hand, is still around, but merely a shadow of its past, now reduced to
a number of canals. They are further threatened by the growth of Mexico City. The axolotl is able to regenerate its limbs, a fact which has not gone unnoticed to scientists, prompting many to employ their use as "lab axolotls," if you will.
Apparently, there are two Pokémon created as a tribute to the axolotl: wooper, and mudkip. Wooper looks to me to be very similar to the axolotl, at least superficially, while mudkip I would now have guessed at, unless I had read it on the Pokémon wiki page. Amusingly, the page is called "On the Origin of Species," presumably a reference to the book by the same title written by Charles Darwin. The link is included below, just in case you want to learn more about either the Pokémon things, or even the axolotl. On The Origin of Species: Wooper