……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. 

Pacific White-sided Dolphin Lagenorhynchus obliquidens

Pacific White-sided Dolphin Behaviour

Pacific white-sided dolphins are gregarious animals that regularly travel in pods of tens and occasionally hundreds of individuals (Wilson and Ruff 1999). The median group size in Canada was 15 individuals (Stacey and Baird 1991) but 1500 dolphins were seen in 2002 near Cape Caution, British Columbia. Pacific white-sided dolphins announce their presence with leaps of several meters above the water and short dashes just below the water surface. It is not clear why Pacific white-sided dolphins make high leaps out of the water but it is likely to assist them in seeing over the ocean. Jumps are often made near boats probably so that the dolphins can get a better look.

Pacific White-sided Dolphin Foraging Behaviour

The gregarious nature of this species is likely a tactic to catch small fish prey such as herring and sand lance. Fish and squid in the diets of dolphins in the eastern Pacific include hake, pacific saury, anchovy, rockfish, mackerel, and squid (Brownell et al. 1999). Dolphins will make repeated short leaps out of the water known as porpoising, when they race off in pursuit of fish.  

Pacific White-sided Dolphin Locomotion

The Pacific white-sided dolphin uses its strong tail flukes to propel it through the water. Four or five strong pumps of the tail is sufficient to launch a leap out of the water. Many marine mammals including dolphins have smooth skin that is continually sloughed and replaced to reduce drag in the water. Olympic sprinters can swim about 2.3 m/s. Cruising speed for many marine mammals is 2.0 m/s whereas dolphins sustain speeds of 1.4 to 3.1 m/s (Costa and Williams 1999). Bottle-nosed dolphins have been recorded at 7.5 m/s (Laing and Norris 1966). The drag from water is greatest when the dolphin is at the surface and it is most efficient to swim a few meters underwater. However, dolphins must come to the surface to breathe and by porpoising, dolphins can both catch a breath and reduce the surface drag.

Pacific White-sided Dolphin Vocalizations

Pacific white-sided dolphins utter a sharp whistle through their blow holes and they echolocate underwater.

Pacific White-sided Dolphin Breeding Behaviour

Female white-sided dolphins reach sexual maturity when they are 10 or 11 years old and males are sexually mature between 10 and 19 years of age. Gestation is about 10 months long and calves are about 1 meter long at birth (Wilson and Ruff 1999).