The baiji, or Chinese river dolphin deemed "functionally extinct" by a team of scientists in December—was downgraded from "endangered" to "critically endangered (possibly extinct)" on the IUCN's 2007 Red List, released today.

Populations of the light blue-gray animal, which lives in China's polluted Yangtze River, have plummeted over the last 30 years.

A possible sighting in August 2007 is currently being investigated by Chinese scientists, but even if one or two dolphins are found, the baiji is almost certainly doomed.

Freshwater dolphins are very vulnerable, because rivers tend to be heavily used by humans and there is nowhere else for the dolphins to go, Caroline Pollock, a Red List program officer, told National Geographic News.

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