Killer whales come in two sizes

A three-year research collaboration between the University of Copenhagen and Aberdeen University reveals that a killer whale is not simply a killer whale. There are two distinct types that grow to different sizes, and have different feeding habits

by Luci Ellis

University of Copenhagen researchers have discovered, in collaboration with colleagues from the University of Aberdeen, that there are two distinct types of killer whales in the waters around the British coast, writes the Scottish newspaper The Scotsman.

The two types of whale have different feeding habits and are inhabit different territories in the waters around the British Isles.

Diet variations

Adult killer whales in one of the groups are bigger and live on a diet of small cetaceans such as dolphins, while the adults in the other group are smaller and feed on herring and mackerel.

The discovery was the result of a three-year study by marine scientists from the University of Copenhagen and Aberdeen University involving bones of killer whales kept at museums in England, Scotland and Copenhagen.

Unexpected results

The research shows that the adults in one of the groups are almost two metres larger than adults in the other group. They also have little tooth wear, while the other group’s teeth are worn down.

Andy Foote of the University of Aberdeen, who led the study, expressed his surprise at the new finding:

»No-one ever thought there were different types of killer whales in the Atlantic around the UK.«

luci@adm.ku.dk

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