Orca or Killer whale (Orcinus orca)

The Orca is a well-known cetacean, made famous by captivity shows. It has a striking skin combination: the primary colour is black, but there is the addition of a grey 'saddle' behind the dorsal, and a brilliant white that covers three areas. Working back from the head, the first of these is the almost elliptical patch behind each eye. The second is on the underside of the jaw, extending back along the throat and belly to the flanks and vent area, where it forms a shape similar to the three prongs of a fork, two reaching up along the flanks while the third covers the vent area. The undersides of the tail flukes are also white. In some regions of the world the primary colour, black, is more of a dark grey. In males, the dorsal fin can reach up to 1.8m in height, and reaches straight up into the air, shaped rather like a triangle. In females the fin is smaller, about half the size, and more curved. The head is rounded, with an indistinct beak, inside of which are 10-12 pairs of large teeth in both the upper and lower jaws. This stocky species reaches a maximum length of 9.75m for males and 8.53m for females. The maximum body weights are 10.5 tonnes and 7.4 tonnes respectively.
The male Orca's dorsal fin is a tell-tale giveaway, being as tall as a man and shaped like a huge triangle. The blow is low and bushy, and they travel in pods of between three and twenty-five individuals, including at least one large male.
Orcas occur from the polar regions to the equator, and are often found among ice floes. They can adapt to almost any conditions, and appear to be at home in both open sea and coastal waters. Occasionally they may enter estuaries, but when they do, they never stray far from the sea.
Known as the 'Wolves of the Sea', Orcas are fearsome predators. They have the most varied diet of all cetaceans, and can tackle prey of all shapes and sizes. Their co-ordinated hunting strategies - working as a team and not as individual units within the pod, akin to a pack of wolves - show their intellegence and cunning. Hunting in this fashion increases the yield of prey per individual, so that none go without. In some areas of the world, one Orca will hunt but shares the catch with the other members of its pod. Hunting normally occurs during dives of less than 100m, with members of the pod co-operating in keeping the prey at or near the surface. Known prey include a variety of both warm and cold-blooded creatures - at least five species of seals, the dugong, thirty species of fish, turtles, some two species of squid, seven species of seabird, and at least twenty-four species of cetacean, including the massive Blue Whale.
The typical family pod can reach a maximum of around fifty individuals, but most often numbers between 3-25. From behavioural studies in Canada, there are two types of pod recognised: residents and transients. Transients form smaller pods of between 1-7 individuals, roaming over a larger area and feeding mainly on mammals. They vocalise less frequently, often change direction abruptly when swimming, and remain underwater for up to fifteen minutes at a time. Residents, on the other hand, form larger pods, have smaller home ranges, and feed mainly on fish. They vocalise frequently, keep to predictable routes, and rarely stay underwater for more than four minutes. Both transients and residents are acrobatic at the water's surface; breaches, spy hops, and tail slaps are common, and there is little aggression within a pod. Mass strandings are rare, but have been known to occur. Studies have also shown that there are differences in vocalizations between pods. It seems each pod (or communities of pod, such as superpods where more than two pods congregate) has its own dialect, and this changes from pod to pod. Cetologists working in Canadian waters can now tell which pod is nearby simply by the differences in vocalizations. The degree of difference between pods' dialects reflect the degree of social interaction between the pods - for instance, if two pods' vocalizations are very similiar, then they interact with each other, maybe coming together as a superpod.
Longevity: Between 25-90 years, with females having a longer lifespan.