Humans all look the same to us
AND then there were three: long-held assumptions that all killer whales belong to the same species have been blown apart by a DNA analysis of 139 orcas. It reveals that there are at least three separate species.
鈥淭hese have all radiated from one another quite recently, from 150,000 to 700,000 years ago,鈥� says of the Southwest Fisheries Science Center in La Jolla, California (Genome Research, ). , hunting habits and diet.
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Ross Sea killer whales from the Antarctic are about two-thirds the size of most orcas, eat only fish and have the smallest eye streak of all. Pack-ice killer whales also live in the Antarctic but have the largest eye patch and hunt seals. Both are greyer than the north-east Pacific transient killer whales living off Alaska, which feed on marine mammals, including dolphins.
The fact that the species have such different diets could explain the difficulties some aquaria have had getting their captive orcas to eat fish. Morin says he has no idea which species Willy, of Free Willy fame, belonged to.
