Baiji or Yangtze river dolphin
Image: Professor Wang Ding
Source: Chinese Academy of Sciences
First large mammal extinction for 50 years.
A paper just published in the Royal Society's journal 'Biology Letters' reports that the exclusively freshwater baiji, or Yangtze River dolphin (Lipotes vexillifer), is now officially extinct.
This represents the first cetacean (i.e. whales, dolphins, porpoises) species extinction as a result of human activity, and the first 'large' mammal to become extinct since the Caribbean monk seal some 50 years ago.
The critical conservation status and impending demise of the baiji has been trumpeted by cetologists for the last 30 years, but to no avail. This makes the extinction of this species, genus and family all the more tragic: the scientific community, Chinese government and public had the hard facts, but dithered instead of taking decisive action. When conservation steps were taken, they were too little too late.
Now, a highly disparate branch of the mammalian evolutionary tree, which diverged from all other cetaceans at least 18 million years ago, is gone. The fossil record shows that the baiji lineage was formerly more diverse and widespread, and just 3-5 million years ago occurred in the shallow seas off western North America, Japan, and, as recent fossil discoveries show, in what are now Victorian waters.
It is true that thousands, if not hundreds of thousands, of other species are critically endangered and dwindling to extinction. Why should we be so concerned at the loss of the baiji? Because it shows that even in the face of dire warnings of approaching doom, even organisms which command the popular imagination can be lost forever through complacency and inaction. No species is exempt, no matter how high-profile.
So now the biodiversity of cetaceans, mammals, and all life on Earth is diminished further. We are left with very few photographs of the baiji, limited tissue samples, and no more than 5-10 museum specimens worldwide.
Mammalia: Cetacea: Odontoceti: Lipotidae: Lipotes vexillifer—R.I.P.
- Erich Fitzgerald, Honorary Research Associate in Vertebrate Palaeontology, Museum Victoria