IDENTIFICATION: A baleen whale (fringed plates in the mouth are used to filter food) reaching 38—48 feet in length and 27–37 tons (males are slightly smaller than females); characterized by its grayish color, tufts of bristly hairs on its head, and distinctive white splotches and bumps on skin surface that differ like “fingerprints” for each individual. DISTRIBUTION: West coast of North America from Baja California to Arctic Ocean; from southern Korea and Japan to Sea of Okhotsk. HABITAT: Shallow coastal waters, fjordlike inlets, open oceans. STUDY AREA: Wickaninnish Bay, Vancouver Island, British Columbia, Canada.
Social Organization
For eight months of the year—during the migration and summering periods—Gray Whales generally travel and socialize in sex-segregated groups (sometimes known as PODS), while for the remaining time the two sexes are together. Gray Whales have one of the longest migration routes of any mammal: they spend their summers feeding in northern waters, while in the fall they head south on a four-month journey to the mangrove lagoons off Baja California where they mate and their calves are born, only to return to their northern waters in the early spring. A few populations of Gray Whales are nonmigratory, remaining year-round in northern waters.
Description
Gray Whales also frequently form same-sex companionships (pairs and trios) that travel and feed together throughout the summer (without necessarily engaging in sexual activity with one another). They swim in an intimate side-by-side position, often with their side fins touching, and travel back and forth along the length of coastal inlets for hours at a time, apparently with no particular purpose other than to be together. Such companions also perform synchronized blowing and diving maneuvers, including feeding and BREACHING (an acrobatic leap two-thirds out of the water, landing with a dramatic splash on their sides or backs). Two whales also often roll over and under each other, rubbing bellies. Both short-term and long-term (recurring) pair- and trio-bonds occur: some last only for a few hours or days, with the whales changing partners several times over the summer; other companionships endure from year to year.
Nonreproductive and Alternative Heterosexualities
Migration in Gray Whales involves a lot more than travel: feeding, nursing, and sexual activity all take place during the journey. Migrating pods are separated according to the sex, age, and reproductive status of the whales: on the northward migration, for example, newly pregnant females usually leave first, then adult males, followed by nonovulating and immature females, immature males, and lastly females with new calves. Male Gray Whales also have a distinct seasonal sexual cycle related to sperm production: during the northward migration and the summer months, their testes are essentially inactive, producing little or no sperm; on the southward migration sperm production resumes and peaks in late fall and early winter in preparation for heterosexual breeding. Consequently, for two-thirds of the year, male Gray Whales are nonfertile, even though they sometimes engage in heterosexual copulation during these times. Combined with the female sexual cycle (with its infertile period in the spring and summer) and the fact that sexual interactions outside the mating season may involve groups of whales (not all of whom copulate), this means that a significant portion of heterosexual activity is nonreproductive. Furthermore, heterosexual courtship and copulation during the mating season also sometimes involves groups of up to 18 whales interacting at the same time, and both males and females mate with multiple partners. During the actual mating act, trios consisting of two males and one female are sometimes involved: one male is a “helper” who does not interact sexually with the female, but seems instead to assist the other two to align their bodies and maintain their position during copulation. Females usually breed only every other year, and some wait two years between calves.
Baldridge, A. (1974) “Migrant Gray Whales with Calves and Sexual Behavior of Gray Whales in the Monterey Area of Central California, 1967–1973.”
Darling, J. D. (1984) “Gray Whales Off Vancouver Island, British Columbia.” In M. L. Jones, S. L. Swartz, and S. Leatherwood, eds.,
*———(1978) “Aspects of the Behavior and Ecology of Vancouver Island Gray Whales,
*———(1977) “The Vancouver Island Gray Whales.”
Fay, F. H. (1963) “Unusual Behavor of Gray Whales in Summer.”
Hatler, D. F., and J. D. Darling (1974) “Recent Observations of the Gray Whale in British Columbia.”
Houck, W. J. (1962) “Possible Mating of Gray Whales on the Northern California Coast.”
Rice, D. W., and A. A. Wolman (1971)
Samaras, W. E (1974) “Reproductive Behavior of the Gray Whale,
Sauer, E. G. F. (1963) “Courtship and Copulation of the Gray Whale in the Bering Sea at St. Lawrence Island, Alaska.”
Swartz, S. L. (1986) “Demography, Migration, and Behavior of Gray Whales