Animal of the Week April 10, 2013 -- Possibly the rarest animal in the world

Red-River giant softshell turtle, IUCN

I often wonder to myself "What's the rarest animal?" Previous animals of the week have explored the theme, with the baiji and Pinta island giant tortoise having breathed their last since this blog started, and the Iberian lynx being vanishingly rare... but then this week's animal is even rarer still, sitting right on the fence between extant and extinct: Rafetus swinhoei (Yangtze giant softshell turtle, Red-River giant softshell turtle), one of the largest freshwater turtle species in the world of which only four known individuals remain.

The four turtles are found in three different locations: two (probably males) live in different lakes in Hanoi, Vietnam, and a male and the only known female are kept in Suzhou Zoo, China. Conservationists hope that the Chinese pair will breed; but despite attempts at mating, of the 100s of eggs laid over the past few years, none has hatched—many are unfertilised, and any that begin to develop stop at a very early stage. The male is at least 100 years old and the female 80, while turtles can live for a long time, these are no spring chickens.

The species has become rare through the familiar depredations of habitat destruction and exploitation. Within their native range, various species of softshell turtle are popular on dinner tables. Some smaller species are farmed, but over the years, many have been taken from the wild, and larger slow-breeding species such as the Red-River giant are particularly vulnerable.

A few years back, a flood washed one of the Vietnamese turtles from its urban lake home into the garden of a local fisherman. After an extensive search the fisherman came forward asking for over $1000 dollars for the turtle to be returned rather than sold to a restaurant that had offered over $4000 for it.

Efforts to save the species include surveys of suitable habitat, but the last specimen in the wild was caught in 1998. Local conservationists have also been looking for specimens in food markets, but until recently the only criterion for identification of potential specimens has been that they are looking for massive turtles, so any adolescents might still have passed under their noses and ended up in cooking pots.

Given that animals were in the wild in the 90s, one might realistically hope that some young wild turtles remain in the native habitat, but if these cannot be found and protected, with each passing year that the pair in China don't produce offspring, the future for the species looks to be fairly short.