With their grace of motion, sophisticated hunting strategies, and close-knit family bonds, orcas have always fascinated humans. But recent studies reveal complexities of social interaction unheard-of in any other mammal except humans.

The Georgia Strait and the outer coast of Vancouver Island, along with the Northwest Strait and Puget Sound in Washinton, are the domain of three Southern Resident pods, dubbed J, K and L. Watch a video of K pod off Whidbey Island in Washington. A much larger Northern Resident pod (about 200 whales) roams the waters around the northern tip of Vancouver Island.

Wisdom of the elders: Resident orcas travel an average 100 - 150 kms a day in multi-generational groups led by elder matriarchs. Unlike any other mammal except humans, female orcas live three to four decades after ceasing to give birth. This "post-menopausal" lifespan is believed to be crucial to maintaining cultural values and traditions. Orcas are also the only non-human mammal where adult offspring of both genders maintain contact with their mother for life.

Social learning: Adult orcas accompany their young on their first hunting forays and direct them toward prey. Mothers have been observed throwing live prey at calves and helping them back to deep water after successful capture. Orcas also learn complex vocal repertoires that differ from group to group.

Listen to orca vocalizations here.

When Southern resident pods join together after a period of separation, they often engage in "greeting" behaviour with intense vocalizations, followed by playful acrobatics.

According to whale researchers Luke Rendell and Hal Whitehead from Nova Scotia, orcas seem to have evolved cultures that closely parallel those found in both chimpanzees and humans. Their complex social interactions, including teaching and learning behaviours, give rise to stable cultures, which are in some respects unique outside the human world.

Threats to orcas: Both the Southern and the Northern Resident pods depend almost exclusively on Chinook Salmon as primary prey. With the Chinook runs in BC in decline  - and one run officially listed as endangered - the orcas are increasingly going hungry.

Meanwhile, a recent study by Canadian and US government scientists has shown that chinook salmon meat is contaminated with PCBs, flame retardants and other "persistent organic pollutants" that accumulate in orcas' body fat over their lifetime, making them one of the most contaminated marine mammals in the world.

The Northern and Southern Resident pods are listed as threatened and endangered, respectively, under Canada's Species at Risk Act. In October 2008, Sierra Club BC joined other conservation groups and retained Ecojustice lawyers in a lawsuit against the Federal Department of Fisheries and Oceans (DFO), challenging DFO's claim that existing law and policy "legally protected" killer whales' crucial habitat.

In February 2009 DFO and Environment Canada issued an Order to protect critical habitat, but the Order was unlawfully limited to protecting the geophysical elements of critical habitat. A second lawsuit was filed and is now active and merged with the first case by court order. Habitat is not just surface area - it includes opportunities to hunt and forage, and must be maintained noise- and pollution-free. Stay tuned -  this case is a precedent for all endangered species in Canada.