Animal World Records
For most animal species, it is hard for me to clearly remember when I saw one for the very first time. But there are some – often those that I find particularly interesting or memorable – that I can vividly recall first laying eyes on. The Chinese giant salamander – the largest amphibian in the world – is one of those animals.
The animal in question was called Professor Wu and I saw him at London Zoo in 2015. At the time, he was the only Chinese giant salamander in the UK and I had been eager to see him ever since the zoo had first announced his arrival the previous year. When I finally peered into Professor Wu’s water-filled tank, I was greeted with great views of a creature with a dark, heavily-built, slightly compressed body, short legs, a paddle-like tail, and a large, broad head with tiny lidless eyes.
There are only a handful of really large amphibians in the world today. The biggest are the appropriately named giant salamanders and there are two main varieties – one in Japan; one in China – and they both live in cold, fast-flowing, oxygen-rich mountain streams in their respective countries. Of the two, the Chinese giant salamander is the biggest. According to London Zoo, Professor Wu measured around 1.3 metres from snout to tail, which makes him the largest amphibian I have seen – but some specimens have been known to reach 1.8 metres in length and weigh more than 50 kg.
Unlike many amphibians, which move between water and land, the Chinese giant salamander is entirely aquatic. Though it has a pair of lungs with which to breathe air, it can also absorb oxygen directly from the water through its wrinkled skin. This hangs in folds along its flanks, increasing the surface area through which oxygen can be taken in. In the wild, it is very choosy about where it lives – only clean, shallow, fast-flowing water will do, for that is where oxygen is most abundant.
As a sit-and-wait predator at the top of its food chain, the Chinese giant salamander is more like a crocodile than your typical amphibian. It feeds on fish and smaller amphibians but, since it has poor eyesight, it must rely mainly on sensory nodes that run in a line on its body from head to tail to find its prey, for these can detect the slightest changes in water pressure.
Although this creature has an exceptionally slow metabolism and can live to be 60 years old or more, very few will achieve that age. The reason? Humans, of course. The wild population has declined by more than 80% since the 1950s, largely thanks to habitat loss and fragmentation, excessive water pollution, and over-hunting for its meat and its use in traditional medicine. Despite being classified as a Critically Endangered species, giant salamanders are still illegally sold for food since it has become something of a fashionable delicacy among the wealthy.
In the ancient swamps of the Carboniferous Period, around 350 million years ago, amphibians were the dominant land animals. Some of them grew to enormous sizes – larger even than a saltwater crocodile. But as the planet became drier, the vast swamps that had once covered the landscape dwindled in size. Most of the giant amphibians died out in a great extinction event at the end of the Permian Period about 250 million years ago, and the survivors, unable to cope with the new hot, dry conditions, were largely eclipsed by their own descendants: the reptiles. Though the Chinese giant salamander is an exceptional size for a contemporary amphibian, it is positively a dwarf in comparison to some of the prehistoric monsters that once roamed our planet.