Diet and Teeth
Resident Killer Whales eat predominantly fish (Salmon, Lingcod, halibut, greenling, and various small flatfish). Although they are often seen in the vicinity of other marine mammals they usually ignore them. There are only a few examples of resident pods attacking seals or porpoises. Transients Killer Whales, in contrast to Residents, feed almost exclusively on marine mammals or seabirds. The favoured prey of transients is harbour seals, sea lions, and porpoises. Very little is known about the diet of the Off Shore species, but it is believed that they prey on fish for at least part of the year, however preying on Marine Mammals is also possible.
Killer whales often hunt cooperatively in pods for food. They work together to encircle and herd prey into a small area before attacking. When hunting a large whale, a pod of killer whales may attack from several angles (generally transients).
The conical and interlocking teeth of killer whales are well suited for a wide variety of prey, from small schooling fish to large whales. The number of teeth varies among individuals - but there are usually 10 to 14 teeth on each side of the jaw, a total of 40 to 56 teeth. Each tooth is about 7.6 cm (3 in.) long and approximately 2.5 cm (1 in.) in diameter.
Adult killer whales eat approximately 3% to 4% of their body weight in food per day, fully weaned calves can eat up to approximately 10% of their body weight during growth periods.
Behaviour
Most studies have been carried out on Resident Killer whales who live in small, close-knit, groups called pods. The size of a resident pod varies from as few as 3 to as many as 50 individuals who tend to travel within specific ranges.
Resident Killer Whales live and travel in groups or pods organized along lines of maternal relatedness. Studies of resident killer whales have been able to identify maternal lineage through the tight bond between mother and offspring. Paternal lineage is unknown.
Transients on the other hand often travel alone, or in groups of two to seven individuals, and their travelling ranges are unpredictable.
The social system of transients is more fluid than the stable associations of residents. A typical transient group might comprise of a mother and two or three off-spring, or perhaps of several adult females of unknown relationship. Some offspring leave their mother's group as adolescents, often following the birth of a younger sibling. Adult male transients are seldom found travelling solely with other adult males.
Activities
Killer whales exhibit a wide variety of activities as they go about their daily lives. The activities of killer whale groups fall into four categories: foraging, travelling, resting, and socializing.
Foraging is the most common activity, and appears where the whales are feeding or appear to be searching for food. Different patterns of foraging are evident in both residents and transients, depending on the type of prey. Members of a pod frequently cooperate in hunts.
Travelling is when a group of killer whales are travelling consistently in one direction in a moderate to fast pace in relatively tight formation. They may travel from one good feeding spot to another, or it could simply be a means of transiting an area.
Members of a group will often rest after foraging. The whales typically group together, diving and surfacing as a cohesive unit. When resting, whales slow down and at times stop altogether, and usually become very quiet underwater. Periods of rest may last from less than an hour to more than 7 hours. Resting is not very common in transients.
Socializing among killer whales includes a great variety of interactions between members of the group. Behaviours seen during socializing episodes include various aerial displays including breaching, spyhopping, tail slapping, beach rubbing, and flipper slapping. Whales may also interact with inanimate objects such as kelp and have also been seen to surf in the wake of passing boats.
Senses and Communication
Killer whales can also be distinguished by the kinds of underwater communication sounds they produce - squeals, squawks, and screams are used for social communication within and between groups. Killer Whale clans, like dolphins, can be distinguished by their different dialects.
Killer whales have acute hearing and also acute vision both in and out of the water.
Echolocation enables them to locate and discriminate objects by projecting high-frequency sound waves and listening for echoes. Killer whales echolocate by producing clicking sounds and then receiving and interpreting the resulting echo.
Life Span
Some males have been known to live well into their 40s and perhaps to 50-60 years old. Females have been known to live to 60-80 years old.
