Petr Velensky uses a meter to show the size of a Chinese giant salamander Karlo in an aquarium at the zoo in Prague, Czech Republic, Sunday, Dec. 20, 2015. Prague Zoo says Karlo is likely to be the biggest living Chinese giant salamander in the world. According to latest measuring done Friday, Karlo is 1.58 meter (5.18 feet) long. The critically endangered species is the largest amphibian in the world. (Petr David Josek / AP)