Orca: who he is and how he lives
Common name: killer whale
- Body length: female: 7-8 m; male: 8-9 m
- Weight: female: 5,500 kg; male: 7,700 kg
- Lifespan: 30-50 years
- Sexual maturity: female: 6-10 years; male: 10-13 years
HABITAT AND GEOGRAPHICAL DISTRIBUTION
L'Orcinus orca of the family Delphinidae it is the famous orca, widespread in all the oceans and seas of the world (although it prefers coastal areas and colder waters). It normally lives at depths of 20 - 60 m, but is also found in much shallower water, even at 30 m in search of food. Its territory is limited to the north and south only by the polar ice pack and sometimes even reaches the mouths of rivers. In practice it is a species considered cosmopolitan.
CHARACTER, BEHAVIOR AND SOCIAL LIFE
Killer whales are not migratory animals so if they find an area where there is food throughout the year they do not move. Only some populations migrate towards the equator, in winter, to return to the poles in summer. They live in very compact groups usually formed by a female with her young, other older and sterile females and an adult male. This group of individuals make up what is called a pod which is the smallest unit that forms the family of killer whales. The different pods are all in contact with each other through sounds and always swim very close and each has its own language that is unique and is passed down from generation to generation.
It has been observed that killer whales often emerge from the water and turn on themselves simply to "take a look around" being curious animals.
They are animals that can be domesticated, in fact they are generally the main attractions of water parks.
The orca has a smooth body and moves with great speed and speed in the seabed. The body of an adult is white on the belly and black on the back, from the chin to the anus. They have a white spot above the eye and a gray spot behind the dorsal fin which is called saddle, which is different in each orca and is used as a distinctive trait of the individual.
The dorsal fin is high and straight and in males it can reach 1.9 m in height while in females it is half and slightly curved backwards. The two pectoral fins are also large and rounded in shape.
The tail is large and powerful and is used by the orca not only to move at very high speeds (even 50 km / h) but also to move the water and produce deafening sounds that frighten the fish.
A peculiarity of the orca when it goes hunting is to emit a particular sound through the echolocator located in the air ducts. By flexing the muscles of the forehead the orca manages to convey the sounds in precise directions and the returning echo is able to tell the cetacean what the obstacle it has encountered is: other orcas, a rock, something edible. This aspect is very important for the life of killer whales as in the seabed, at a certain depth, the sight cannot be of any help. The organ that allows the orcas to exploit this peculiarity is placed in the lower jaw. The sound waves that come back enter the jaw where there are bones similar to those found in the human ear and from there travel to the brain via the auditory nerve.
They are cetaceans odonceti that is to say provided with teeth (the whales are instead mysticet cetaceans) in fact each jaw has from 20 to 26 conical teeth. Each tooth is curved in order to better grasp and tear the prey.
Killer whales emit various types of sounds which are used both to communicate with each other and to navigate these are whistles, sounds and screams used according to different circumstances.
Each pod has its own distinctive sound that is passed down from generation to generation for up to 6 generations.
The orca is considered the predator par excellence. The diet is extremely varied, ranging from whales to dolphins, sharks, octopuses to sea turtles as well as seabirds, seals, sea lions, otters and other animals. Contrary to popular belief, it does not indiscriminately hunt everything in its path but normally focuses on what is most abundant in the area where it is, adapting its hunting techniques accordingly. Check out this video that shows how seals hunt, even going as far as the shore.
On average he eats 45 kg of meat a day, but he can eat even more if there is food available.
The killer whale rarely hunts alone, it is more common to hunt in groups, such as ilupias ileoni. For example, if it has to attack a school of fish, these are pushed by the whole group towards natural barriers and then once trapped, they are eaten by the killer whales that jump into the middle of the school with their jaws wide open.
If they see a seal on a small iceberg, they manage to drop it into the water by swaying the iceberg with a series of coordinated actions.
REPRODUCTION AND GROWTH OF SMALL
A female orca mates indifferently with several males, even with those that belong to different pods. Therefore the baby of a pod is not necessarily the son of the male of that pod but nevertheless is still cared for by the whole group.
Mating can take place at any time of the year even if it has been seen that it is more frequent during the summer period. Although females reach sexual maturity between the ages of 6-10, they only begin mating around the age of 14-15.
The gestation lasts about 14 months and after this period a baby is born weighing about 135 kg and is 2 to 2.4 meters long (twin births are very rare). It is usually given birth in shallow water and as soon as the mother or someone in the group is born, she immediately brings it to the surface to breathe.
In the first few weeks of life, the baby spends all his time sucking his mother's milk, about every 20 minutes. The female has special muscles in the mammary gland that allow milk to be sprayed into the baby's mouth. On average, a baby is breastfed for about two years.
Since the killer whale is a very caring mother who dedicates herself body and soul to her baby, females usually give birth every 6 years and stop having babies around the age of 40 so a single killer whale, in the course of its life, puts in the world no more than 4-6 children (during the 25 years of reproductive life considering that the gestation lasts about 14 months).
Killer whales are animals at the top of the food chain, therefore their only real enemy is the man who hunts them (fortunately not with the same frequency and intensity as whales) for oil and for the meat that is sold for consumption. human or used as a fertilizer or as a bait. Only a young whale can be attacked by other killer whales or by particularly large sharks.
STATE OF THE POPULATION
The orca is classified on the IUNC Red list among animals DATA DEFICIENT (DD): in practice that it does not have sufficient data available to make a direct or indirect assessment of its risk of extinction based on its distribution and the state of the population.
The species is listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Fauna and Flora, known simply as Washington Convention) which includes species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid exploitation incompatible with their survival.
SOCIAL, ECONOMIC AND ECOSYSTEM IMPORTANCE
They are usually the main attraction of water parks.
The orca has been the protagonist of a series of films Free Willy where the story of friendship between a child and an orca was told, below we report a video with some sequences. The orca protagonist of the film was called Keiko, and she died in 2003 of pneumonia while trying to reintegrate her into the wild. He was 27 years old. The song, which has become very famous, Will You Be There is written and sung by Michael Jackson.
To hear the noises emitted by this animal, go to the article: The sounds emitted by the orca.