……objective science for conservation…….

The Pacific WildLife Foundation is a non-profit coastal and marine research and education society  that inspires an appreciation for objective scientific research and conservation of the ocean. We conduct original research, develop novel education programs, and inspire an appreciation for conservation of the ocean. 

Gray Whale Eschrichtius robustus

Gray Whale Behaviour

Gray Whale Feeding Behaviour

Gray whales eat benthic amphipods, ghost shrimp and a variety of planktonic crustaceans. It is the only baleen whale that habitually forages on the sea bed which it accomplishes by rolling on to one side, sucking sediments in through the lips, and using the tongue to filter the sediment through baleen plates.  Our studies off the west coast of Vancouver Island indicate that gray whales shift from one type of prey species to another over the summer season depending on which is most plentiful (Darling et al 1998).  Preliminary time budget observations suggest that gray whales off Vancouver island, spend about 70% of their time feeding during the months July to September.

During the summer gray whales often feed and travel alone or in small groups.  When feeding on the bottom they typically breathe 3 or 5 times in quick sequence before submerging for 3 to 5 minutes. The blow from this species appears heart shaped from the front and rises about 1.5 m in the air.

Gray Whale Breeding Behaviour

Gray whales calve every two or three years off western Baja California. Mating is a scramble between many males attempting to mate with each female in estrus. Females come into estrus in late November and many are fertilized from that time through December. Those females that fail to conceive may come into a second estrus in January. Males have relatively large testes which likely reflect strong sperm competition. The fetus grows to about 4m over a year until the final month when growth slows. In late January, the pregnant females gather in shallow lagoons to give birth, Laguna Guerrero Negro, Laguna Ojo de Liebre, Laguna San Ignacio and Bahia Magdalena being the most notable nurseries. The young calf is immediately the target of ectoparasites – the barnacle Cryptolepas rhachianecti is unique to the gray whale. There are also three species of ‘whale lice’, two of which are found only on the gray whale.  Young calves are nursed for several weeks and then depart north with their mothers in May. Calves follow their mothers north in spring to the feeding grounds between northern California and the Chuckchi Sea. They become independent 7 to 9 months later. Males and females become sexually mature between 5 and 11 years of age.

Gray Whale Vocalizations

Gray Whales utter moans, modulated pulses, clicks and calls. They range in frequency from 0.02 to 20 kHz (Table 4-1 in Wartzok and Ketten 1999).