The orca can live in all the seas and oceans of the world and lives both in the abyss and in the shallows near the coasts, sometimes even reaching the mouths of some rivers. Normally, however, the orca prefers to live in both arctic and antarctic cold waters where, in summer, it hunts among the ice floes.
Only a few populations migrate to the equator in the summer, much like the gray whales that migrate near the US coast. Sightings in the Mediterranean Sea are quite rare. It is difficult to estimate the number of individuals in the world, according to the International Union for the Conservation of Nature there are no precise data: one of the estimates considered most reliable is about 50,000 specimens.
From the skeleton of Old Tom, an orca that helped whalers hunt whales, and who was rewarded by letting them eat the tongue and lips of killed prey, an estimated age of about 90 years was calculated, but subsequent studies on the animal's remains reduce this figure at 35 years.
Old Tom was found dead in Twofold Bay on September 17th, 1930. The offspring of killer whales remain with their mothers even after reaching adulthood. These help them find a partner to make sure they have an offspring. A female killer whale can breed with males of even several pods.
In this case the males, not being able to recognize their children, take care of all those present in their group. After about 1 and a half years of gestation, the female gives birth to only one young, usually in shallow water, and then immediately brings it close to one of her relatives.
For each female, the interval between births goes from 3 to 8 years, mainly due to prolonged parental care. The maturity occurs in the female at 10 years, the male instead matures at 16 years and 5.8 meters in length. The orca normally lives in groups consisting of the female, her young, sterile older females and an adult male.
This is a basic matrilineal family also called pod. All the members of this family communicate with each other through sounds of various kinds and each pod has its own language. The orca has a specific organ placed on its forehead that it can use as a sonar. All objects hit by sound waves send back an echo that killer whales perceive as an animal or a rock to be avoided.