Can still fall prey to killer whales
As shallow-water feeders, gray whales stay close to coasts.
Gray whales become sexually mature at around eight-years old. Calves can swim as soon as they are born and can double their weight in about three months, and double their length in about two years. Mother and calf form a very close attachment, with the calf spending the majority of its time swimming close to its mother.
It's difficult to tell how old gray whales are because they have no teeth (which can be used to estimate age in other mammals). They may die of natural causes but sometimes fall prey to killer whales.
During the summer, gray whales are found alone or in small groups. It has been suggested that mating occurs in the winter, and some mating activity has been witnessed in the breeding lagoons. Pregnant females return to the feeding grounds for the summer, returning to breeding areas to calve the following winter. The gestation period lasts for about 13 months, and they breed every two to four years.
Gray whales, like other baleen whales, strain their food from the water through baleen plates. However, they are different from other shallow feeding great whales in that they prefer prey that lives near or on the sea floor. They are the only large whale that feeds primarily on the ocean floor, rolling in the mud to suck benthic organisms from the sea bottom.