page_title: Michael Bigg
section_title: Killer whale taxonomy and social structure
hierarchical_section_title: Michael Bigg / Killer whale taxonomy and social structure
caption_attribution_description: Orcas of various ages in Johnstone Strait, British Columbia
context_page_description: Dr. Michael A. Bigg was a Canadian marine biologist who is recognized as the founder of modern research on killer whales. With his colleagues, he developed new techniques for studying killer whales and conducted the first population census of the animals. Bigg's work in wildlife photo-identification enabled the longitudinal study of individual killer whales, their travel patterns, and their social relationships in the wild, and revolutionized the study of cetaceans.
context_section_description: In 1976, federal funding for Dr. Bigg's killer whale research ended, and he was reassigned to other projects. It was not until the early 1990s after Bigg had died, that the Department of Fisheries & Oceans again began to provide funding for whale research on the west coast. Still, Bigg continued his research on his own time for 14 years. Marine biologist Dr. Graeme Ellis who began working with Bigg in 1974, said that in the times that funding for killer whale research was absent, "it had become so fascinating we couldn't let it go - for many years it was done with our own money and our own time." In their book Guardians of the Whales, Bruce Obee and Graeme Ellis wrote:
  "While studying seals, sea lions, or other species in the field he disregarded departmental memos ordering him to forget about whales... He traveled the coast on his own time, soliciting help from anyone and everyone with his infectious fervor. He'd think nothing of asking a float plane pilot to land beside a sport fisherman, then persuade the fisherman to run him over to a nearby pod of whales and click pictures for the rest of the day."
  During this time, Dr. Bigg together with friends and associates, assembled what has been described as "one of the most thorough data sets for any wild mammal... the killer whale was transformed from one of the least known to among the best understood of all cetaceans." His records included births, deaths, diet, and social associations. Bigg and his colleagues gathered enough data to produce a complete family tree documenting the maternal-side relationships of every killer whale on the British Columbia and Washington coasts.
  One of the key discoveries of Dr. Bigg's team was that there were two types of killer whales living near the British Columbia coastline: residents which ate almost exclusively fish, and transients which hunted marine mammals and other warm-blooded prey. Resident and transient killer whale societies are separate, and the two types tend to avoid each other. The resident killer whale population of British Columbia and Washington is further divided into two communities, one northern and one southern, that do not interbreed.
  Another discovery was that resident killer whales have one of the most stable social structures of any animal species. Pods of killer whales had previously been assumed to consist of a few adult males and a harem of potential female mates. Bigg's team slowly realized that killer whale pods are matrilineal: killer whales travel not with their mates, but with their mothers and maternal relatives. The basis of resident killer whale groupings is the rule that each animal travels primarily with its mother throughout their lives.
  Although his research was based in the eastern North Pacific, Bigg mentored killer whale researchers from around the world, who sought his advice for their own studies.
caption: Bigg and his colleagues discovered that resident killer whales travel in extremely stable matrilineal groups.
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