Just two weeks after the World Wildlife Fund declared the Vietnam Javan rhinoceros (Rhinoceros sondaicus annamiticus) extinct comes the announcement of another rhino extinction, this time the western black rhino (Diceros bicornis longipes) of Africa.

The declaration came last week from the International Union for Conservation of Nature and Natural Resources (IUCN) as part of the latest update to its Red List of Threatened Species, which tracks the conservation status of endangered animals and plants around the world.

The loss of the western black rhino was, sadly, expected. After decades of heavy poaching and weak protection, the species was last seen in 2000 in Cameroon—a country known for its violence and corruption—at which time the last 10 or so individuals in this subspecies were thought to be too spread out to find each other and breed. The IUCN declared the western black rhino "likely extinct" in 2006; all attempts to find them since then have proved fruitless, and conservationists have now given up any hope of finding the animals alive.

So there we have it: two rhino extinction announcements in the course of a month. How many more can we expect in the coming years?

By the way, the remaining rhino species in Africa and Asia remain under threat, as poaching is now at an all-time high this year, already beating last year's previous record. Expect that number to continue to rise.

(See my story from two weeks ago for the status of all other rhino species and subspecies.)

With that news out of the way, let's catch up on some other species recently covered in Extinction Countdown:

Canada's Polar Bears Inch Toward Protection

The Canadian Environment Minister has named polar bears (Ursus maritimus) a "species of special concern" under the country's Species at Risk Act. This doesn't actually add any protections for polar bears, which face tough conditions due to climate change, but it does require the Canadian government to come up with a comprehensive species management plan within three years.

The most vocal voices against this declaration come from Canada's Inuit communities, which have so far maintained their traditional rights to hunt polar bears.

In other polar bear news, a study of the animals in Greenland found that they were carrying a "cocktail of environmental toxins" in their bones and tissues. Like other apex predators, polar bears eat animals that have eaten other animals, allowing toxins to accumulate as they climb up the food chain. It is not yet known how the toxins are affecting the polar bears.

Squirrel Numbers Climbing

Speaking of species that cost a lot to conserve, last year I reported on a cancelled $1.25 million plan to help protect the endangered Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis). Well luckily, the squirrel had a good year even without the investment. There are now 240 of the animals, up 12 percent from 214 in 2010. That's still way below the previous high of 550 in the 1990s, but for a species that was once thought to be extinct, it's an improvement. And a rare one indeed.

Photo: Western black rhino skull from 1911, via Wikipedia