Orca  (Orcinus orca)

Orcas are the top predator in the sea and have an extremely broad diet, including fish, gulls, penguins, turtles, squid and marine mammals, even including large whales such as grey and blue whales (2). They spend their life in stable groups, called pods (2), which hunt co-operatively (6). Long-term studies off Canada have shown that orcas occur as 'transient', 'resident' or 'offshore' populations, which have different hunting styles and social organisation (4). Orcas are extremely active and acrobatic; they are one of the fastest animals in the sea and often breach (clear the water), lobtail (slap the tail flukes on the surface of the water), and spy-hop (bring the head out of the water) (4). Females become sexually mature in their teens and produce a single calf every three years until they reach around 40 years of age (6). After the gestation period of up to 17 months, calves are suckled for about a year (6). Killer whales live to between 50 and 100 years of age (6).