Sunday, November 22, 2009

The Gray Whales Northern Migration

In March whales are returning northward along the Oregon coast. The northbound migration begins with immature animals adult males, and females without calves. These animals pass the Oregon coast from early March through April. Breeding sometimes is observed at this time. Calves usually are rambunctious but stay close to their mothers as they become more coordinated and develop an insulating blubber layer. Calves are at least a month old before they migrate north with their mothers. Mothers and calves are the last to
leave the lagoons and move somewhat more slowly, passing Oregon from late April through June.

During the spring migration, if the weather is good, you can see whales within a few hundred yards of coastal headlands. The full round-trip migration from the Baja calving lagoons to the Bering Sea and back is 10,000 miles, the longest known for any mammal. Other whales also are known to migrate between summer high-latitude feeding grounds and more temperate low-latitude
breeding and calving areas. Researchers know more about the gray whale because it moves close to shore. This movement has led to speculation that gray whales navigate by staying in shallow water or keeping the surf noises to one side or the other, depending on their direction of travel.