20€ off on SILVER, GOLD and PLATINIUM passes, only until November 25th 2022!
This is, along with the pilot whale, one of the only dolphin species to show significant sexual dimorphism. As an adult, the male has very large fins, including the dorsal fin, which can be up to 2 m high. The dorsal part of the latter is straight compared to that of the female which is sickle-shaped. Sexual maturity is reached at around 7 years old in females and 10 years old in males. At birth, the calf measures approximately 2.5 m and weighs 120 to 160 kg. Once they have passed their first 6 months, their longevity is estimated to be between 30 and 40 years depending on the region. However, mortality before 6 months is about 50%.
The killer whale is found in all the world's oceans and seas. It can be seen from the equator to the poles.
It inhabits either coastal areas or areas rich in prey.
The Killer Whale is a gregarious animal. The group may consist of only a few individuals or as many as several dozen. Social bonds are very strong between individuals in a group, especially between mothers and their young. A hierarchy is clearly established in the group through different behaviours (biting, jaw slamming, tail fin slamming, head butting, etc.). The basic structure is matriarchal, with the females guiding and managing the group. It is probably because of their importance in the group that female Killer Whales may exhibit menopause, which is the case for few species.
Despite these common characteristics, Killer Whales behave very differently depending on where they live; they have a culture that they pass on from generation to generation. There are 10 ecotypes (sub-species) whose lifestyles can be very different.
At the top of the food chain, Killer Whales have no natural enemies. Their diet consists mainly of fish (including rays and sharks), penguins and other marine mammals (sea lions, seals, porpoises, whales, dolphins). The proportions of these prey in their diet as well as the hunting techniques used vary according to the respective populations. It is one of the few species that passes on its knowledge to the next generation. In Antarctica, they coordinate their movements to create a wave that can cause Weddell seals to slip off their ice islands. In Patagonia, scientists have observed female Killer Whales instructing groups of young whales to voluntarily strand themselves in order to hunt baby sea lions. This training can last up to 20 years!
Equipped, like all dolphins, with sonar, they are able to locate their prey more easily. However, aware that these sounds can be picked up by their prey, they do not use them when hunting mammals that could detect their presence and escape.
Decline in fish stocks:
The decline in food resources caused by overfishing and the breakdown of their habitat is one of the greatest threats faced by Killer whales. The populations resident in the north, specialising in salmon hunting, are the most affected.
As Killer whales are at the top of the food chain, they ingest chemicals (particularly PCBs) accumulated in the tissues of their prey. Populations feeding on large prey such as marine mammals appear to be more affected than others. Newborns suffer greatly from this bioaccumulation as a very large proportion of the accumulated contaminants are excreted through breast milk. It is estimated that 90% of the pollutants are passed on to the 1st baby which greatly increases the risk of mortality.
Eat fish from eco-responsible fishing.
Decrease pesticide use.