Four Endangered Whales Found Dead

Four endangered whales have been found dead in the past six weeks — including two just this week, scientists said.

A dead North Atlantic right whale was spotted off the coast of Georgia on Wednesday, a day after one was found off Nantucket Island in Massachusetts. Two were found in late December off Virginia and Nantucket.

Tony LaCasse, a spokesman for the New England Aquarium, said biologists hope to perform autopsies on the whales found this week to determine the causes of death.

"What we do know is losing that number of animals in such a short period of time puts us generally on a slippery slope to extinction," he said.

"There are only 300 right whales left in the world and every single right whale is incredibly valuable to the Right Whale Recovery," Laura Engleby, a marine mammal biologist with the National Oceanic and Atmospheric Administration's Fisheries Service, said last March on CBS News' The Early Show.

That's because right whales were heavily whaled for many years. Whalers found them to be the "right" whales to hunt: They are big, slow and float when they are killed.

Commercial hunting stopped about a century ago.

According to NOAA, the northern right whale populations are believed to be close to extinction, while the southern populations are doing better, with the largest groups seen off western Australia, South Africa, and Argentina.