We explain what an orca is, what its habitat is, its diet, reproduction and other characteristics. Also, how dangerous they are.
What is an orca?
An orca or orca whale is known as an marine mammal of the order cetaceans and from the same family as dolphins (Delphinidae), common in all the world's oceans. Its body is recognizable by its black (on the back) and white (on the belly) coloration, as well as for being one of the largest and most versatile marine predators in the world.
Scientific name Orcinus orcathis is the largest known species of dolphinid. The species evolved in the Pliocene around 5.3 million years ago, moving away from the ancestors of today's dolphins.
It has a reputation for being a fearsome predator, capable of killing other large carnivores such as the white shark, and at the same time for being a gentle and intelligent animal capable of interacting affectionately with humans in captivity.
Killer whale hunting was common in 18th century Japan, while large whaling industries ignored them, given the low amount of oil that can be extracted from their bodies, compared to whales and sperm whales.
Since the end of the 20th century, however, the sighting of orcas has become an important tourist attraction, as has their breeding in captivity and their incorporation into aquatic shows, given that they are a fairly intelligent animal. Captivity causes dorsal fin atrophy in this species due to the lack of exercise of their dorsal muscles, by constantly staying on the surface.
See also: Aquatic animals
Characteristics of killer whales
Orcas, in general, are characterized by the following:
- They are marine mammals, adapted to submerged life, with characteristic black and white body endowed with hydrodynamic proportions.
- The males of the species They can measure up to 9 meters long and weigh about 5.5 tons, while females range around 7.7 meters in length and 4 tons in weight. Both sexes have an extensive dorsal fin that can reach 1.8 meters in length.
- It is a marine super predator born, without rivals or natural enemies, which uses echolocation (emitting sound underwater) to perceive its prey.
- are migratory animals which make up more or less extensive pods, capable of coordinating an attack on larger prey, such as whales or white sharks.
- Four different types have been identified of orcas, whose physical distinctions are more or less evident, and which could indicate that new species have formed over time. This is a species under intense study by marine biologists.
- are highly intelligent animals among the few capable of recognizing themselves in a mirror. They are capable of playing, imitating other animals and transmitting lessons to their offspring.
Where do orcas live?
Orcas have a presence in absolutely all the world's oceans from the cold waters of the polar oceans to the warm waters of the tropics. They are animals with a lot of continuous movement, being able to swim up to 60 kilometers a day and dive to depths of 150 meters repeatedly.
What do orcas eat?
The diet of orcas is strictly carnivorous and among its usual prey are salmon, tuna, herring, rays, cod, squid, penguins, whales, sharks and even other marine mammals, such as seals, porpoises, sea lions and dolphins. Human beings are not among their usual prey.
How do orcas reproduce?
As in all mammals, Orca reproduction is sexual and viviparous but unfortunately not much is known about the reproductive habits of wild orcas.
From the study of specimens in captivity, it is known that are a polygamous species, whose mating periods are variable and unpredictable depending on the individual, and that its gestation period lasts between fifteen and eighteen months, at the end of which a single calf is given birth per birth, at any time of the year.
How long do orcas live?
The average lifespan of an orca is comparable to that of a human being. Once they have passed the risky stages of infancy (when around 37-50% of calves die), orcas can lead lives of between 60 and 80 years, if they are males, and almost 100 years if they are females. Like humans, female orcas suffer from the end of ovulation and reproductive life (menopause) after a certain age.
How dangerous are orcas?
There are records of attacks by orcas on human beings, generally accidental, resulting from confusion (a surfer who resembles a seal) or stress due to situations typical of captivity.
However, Human beings are not among the orca's usual prey and rather they tend to be curious and playful when interacting with human beings, as long as they do not represent any immediate danger to them, of course.
A famous case of a particularly aggressive orca was that of Tilikum, an Icelandic orca that was involved in the deaths of three of its trainers at SeaWorld, in the United States. His story is told in the documentary Blackfish2013.
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References
- “Orcinus orca” in Wikipedia.
- “Orca” at Oceanwide Expeditions.
- “Orca (Killer whale)” in National Geographic.
- “Killer whale (mammal)” in The Encyclopaedia Britannica.
