I said at the beginning of the New Year that I wanted to write about more of the factual subjects that I’m interested in on this blog; so I’m planning on writing some posts on interesting animals, both living and extinct. Let’s start with an amphibian that you may have seen mentioned in the news this week: the Chinese giant salamander (Andrias davidianus) – or, as it is sometimes known in China, “baby fish”, as its vocalisations are thought to sound like a crying baby.
As you can see in the picture (taken by myself at ZSL London Zoo in 2015), the Chinese giant salamander is both very odd-looking, and far bigger than the average salamander. In fact, it’s the biggest amphibian in the world today, capable of growing up to 1.8 metres long. It belongs to a family called the Cryptobranchidae, whose history in the fossil record dates all the way back to the Jurassic Period, 170 million years ago – the only other cryptobranchids still alive today are the Japanese giant salamander, and the hellbender from the eastern United States.
Chinese giant salamanders are completely aquatic, and like to live in rocky streams in mountainous, forested areas. Adults breathe underwater through their skin; the folds along their sides are to increase the available surface area for respiration. Primarily sensing their prey through vibration due to having poor eyesight, they will eat just about anything they can catch, including smaller members of their own species. These salamanders do have a softer side, however: after a female lays her eggs – hundreds at a time – the male takes responsibility for guarding them until they hatch.
Unfortunately, this fascinating amphibian is Critically Endangered in the wild. Not only is its habitat being destroyed and polluted, but giant salamanders are also harvested to eat, and for use in Chinese medicine. Farms in China raise millions of salamanders for their meat; some of these will be released into the wild, but captive animals can both spread disease to wild populations and compromise their genetic integrity. Recently, a genetic analysis of giant salamander populations confirmed the existence at least five genetically distinct lineages; lack of knowledge about this could lead to the extinction of unique genetic diversity, if it hasn’t already. Many challenges remain – preserving suitable habitat and genetic lineages, stopping illegal poaching, and improving farming practices – if Chinese giant salamanders are to be saved from existing only on farms, destined for Chinese dinner plates.
Yan et al. (2018), The Chinese giant salamander exemplifies the hidden extinction of cryptic species. Current Biology 28 (10), pR590-R592.