Saturday, July 3, 2010

Baiji

Writing about extinct animals is always a challenge to me because in so many circumstances the information is just not there. We know about the creatures from fossils that are so often incomplete, or from unreliable sources in the case of the more recently extinct animals. The Baiji falls into neither of these categories, as its functional extinction was sadly announced only four year ago, in 2006. If there are still individuals out there, they would be the rarest mammals on earth.

Image from Wildlife Extra
Only a hundred years ago thousands of these freshwater dolphins, also known as Chinese River Dolphins, swam the length of the Yangtze. Industrialization and fishing practices have led to their fast decline, and in 2006 a six-week, multi-national expedition uncovered no specimens. Reports of an sighting surfaced in 2007, but even if a handful of individuals remain, the population is unlikely to be sustainable. They have never been bred in captivity, though the Chinese government and international agencies have made steps in the past to set up programs.

Baijis (Lipotes vexillifer) have existed for millions of years, and are recorded in Chinese history for nearly two millennia. They are one of five species of freshwater dolphin, all of whom are listed by the IUCN as between vulnerable and critically endangered.

Baijis, like all dolphins, hunt by means of echolocation. They typically feed during the day and consume a variety of fish species that are found on both the river bottoms and on the surface. Another similarity to their saltwater cousins is their social organization. They live in small groups and use a variety of clicks and whistles for communication.

Physically, the Baiji grows to be about 8 feet long and weighs 500lbs. They have grey bodies, very long snouts, low dorsal fins, and small eyes that are functional but not especially useful in the murky waters. Gestation is 10-11 months, and one calf is born at a time. Life expectancy is around 25 years, based upon dentition and captive individuals.

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