Scientific order Cetacea (from Latin "cetus" meaning whale).
Sub-order Mysticeti (from Greek "mystax" meaning moustache, and "cetus")
 

Identification

   Gray whales can be differentiated from other similar looking whales by the lack of a dorsal fin 6-12 low bumps along their backs and two to five deep creases rather than longitudinal ventral grooves on its throat.  Gray whales also have sparse hairs on their body, which are retained throughout their life.  Their gray color comes from scars produced by marine crustaceans such as barnacles and whale lice that attach to their skin in warm water.

   Whales are air-breathing mammals.  Their nostrils are on the top of their head and are called blowholes.  Like other members of the Mysticeti, Gray whales have a pair of blowholes (Odontoceti, or toothed whales, have only one).  Their exhalation or "blow" from their 8-inch long blowholes can reach 12 feet above the water and might appear heart-shaped on wind-free days.

   An adult gray whale averages 35-50 feet in length.  Females are slightly larger than males.  Their weight may exceed 35 tons (70,000 lbs).  For comparison, an adult male African elephant can weigh up to 6.6 tons or 13,200 lbs.

Migration

   The California Gray whale's migration takes place along the Pacific shore of North America, between the Arctic Ocean and the protected lagoons of western Baja.  This migration is about 10 to 12,000 miles round trip.

   Whales leave their northern feeding grounds before the ice closes in October and November, traveling about 100 miles per day at 4 to 5 miles per hour (roughly 2 months traveling each way).  Pregnant cows lead the migration.  Newly pregnant females lead the return migration north during the spring months of March and April.  Females with new born calves remain the longest so that the calves can nurse and build up the heavy blubber layer needed for warmth and energy during the return journey to the Arctic.

   Although most grays migrate, some do not go all the way to Baja and some seem to live year-round various west coast locations and offshore areas including the Farallon Islands near San Francisco.  Other Baleen whales such as Humpbacks also migrate seasonally from the poles to equatorial waters.  If we see a whale from Mendocino's coast during the summer months, it is most likely a Humpback.  On rare occasions, we also can see Blue Whales.  Toothed whales do not migrate in a predictable seasonal pattern, but tend to follow prey.  We often see Orcas or other dolphins or porpoises off California at various times during the year.

Social Behavior

   Unlike the highly social toothed whales such as bottlenose dolphins and Orcas, adult gray whales do not appear to form tight family units though they do migrate in groups with flexible membership and gather at the breeding grounds.

   Gray whales exhibit care giving.  They will give support or remain with a wounded whale or assist a stranded youngster to get back in the water.  Newborn calves rarely get far from their mothers and mom will defend her young aggressively.  This dangerous adversary came to be known as the "devilfish" by Pacific whalers who experienced this behavior firsthand when they attacked the infant whale to bring the mothers within range.

   Gray whales produce a variety of sounds including grunts, low frequency rumbles, and clicking noises.  The low frequency sounds produced by baleen whales can be heard for hundreds of miles under water and may be used to determine relative depth or the distance from objects in the water.  There is some anecdotal evidence that baleen whales may also use sound for defense or to stun food items

Mating

   Bulls (adult males) and cows (adult females) may begin courtship and mating as they head south from the Bering Sea.  Mating continues throughout the calving season and return migration.  Both sexes appear to copulate with several partners over the course of the breeding season high-speed chases and lots of splashing and rolling around at the surface are common.  A gray whale penis is easy to identify at a distance.  It is light in color, pointed at the tip, and about 7 feet long.

Calving

   Gray whales are homeothermic mammals.  In other words, they maintain a constant internal temperature.  Like all mammals, the female bears live young, and nurses her baby with milk produced from her body.

   The gestation period is 12 to 13 months.  Females give birth in the winter, wean their young in 8 to 10 months, and can then mate again the following winter, though not all do.  They are thought to reach sexual maturity at about 5-11 years.  Gray whales live an average of 30-40 years, with occasional individuals living up to 60 years.

   A newborn calf weighs an average of 1,500 pounds and is about 15 feet long.  Newborn calves nurse from a pair of shallow slits or folds of skin on the mother's belly.  Pressure causes the nipples to extend outward and forcibly eject milk into the calf's mouth.

   Newborns consume about 50 gallons of milk a day.  The milk has a high fat content of 35 to 55%.  By comparison, cow's milk is about 4% and human milk contains only 2%.  A baby whale born in February will double its body weight by August.

Feeding

   Rather than teeth, all whales of the order Mysticeti have baleen, flexible, fibrous, fringed plates attached to the upper jaw.  The Gray whale's baleen is relatively short and creamy white in color.  Baleen is made of keratin, the same protein as our fingernails and hair.  Gray whales feed on animals living just under the surface of the Arctic Sea floor during the summer.  Diving to the bottom, the whales use suction to scoop up a mouthful of mud and water and force it through the baleen.  Crustaceans (amphipods) and other small bottom dwellers are trapped in the baleen and then swallowed.  Gray whales have also been observed eating krill, a species of shrimp that occurs in clusters near the ocean's surface

Conservation

   Gray whales were hunted for centuries by various native cultures of Asia and North America.  Commercial whaling began to seriously deplete the population in the 19th century.  North American and European whalers discovered easy hunting in the Baja lagoons and near shore migration habits of the Gray whale.  There were 15 shore processing and hunting stations from Northern California to Baja for 45 years.  By 1890 the population was so decimated that whaling was no longer lucrative.  Recovery of the  population and development of steam and diesel powered boats allowed renewed hunting in the early 1900's.

   In 1946, Gray whales were declared a depleted and endangered species.  Commercial whaling was banned in the United States in 1951 and various laws such as the Endangered Species Act of 1964 and the Marine Mammal Protection Act of 1972 though other countries hunted within sight of the California coast until the US territorial limit was increased to 200 miles off shore in the later 1970's.

   Once whaling was restricted, the same coastal migration and winter gathering in Baja lagoons that led to near extinction facilitated the successful recovery of gray in some areas.  At one time, there were three gray whale populations.  Today, approximately 18-23 thousand Gray whales migrate, feed and calve in the Eastern Pacific and the species was removed from the Endangered Species list in 1994.  Unfortunately, the North Atlantic population of Gray whales is extinct and the western north Pacific population is seriously endangered with estimates of only 100-200 animals remaining.