Alias:Mirounga angustirostris,Northern elephant-seal,Northern elephant seal
Outline:Carnivora
length:3-6m
Weight:900-2700kg
Life:About 20 years
IUCN:LC
The scientific name of the Northern elephant seal is Mirounga angustirostris, and its foreign name is Northern elephant-seal. It is a large seal-like animal.
The Northern elephant seal has large, round, black eyes. The width of the eyes shows that they mainly hunt by vision. Like other seals, northern elephant seals have atrophied hind limbs that become part of the tail and caudal fin. Each foot has five webbed toes. This pair of flexible feet can be used to push water. The pectoral fins are rarely used for swimming. The hind limbs are not suitable for movement on land, and northern elephant seals use their fins to support and propel their bodies. They can walk very quickly over short distances, up to 8 kilometers per hour.
The nose of the northern elephant seal is very special, like a cockscomb, and can grow as the body grows. The nose of a male can be more than 40 cm long, quite like an elephant's trunk. When excited or angry, their noses will swell with blood and make a loud sound. The tiny veins of northern elephant seals surround the arteries to obtain heat, so that they can adapt to cold climates.
Northern elephant seals eat more than 30 species of fish and cephalopods, including squid, octopus, hagfish, porbeagles, and small sharks. They are diurnal and forage in the pelagic zone, spending long periods of time underwater. They can dive to depths of 300 to 800 meters, with males able to dive up to 1,500 meters. They rarely forage at depths less than 200 meters. Their dives are long, averaging about 20 minutes for males and shorter for females, with a rest period of about 3 minutes between dives. The deepest dive was held by a female, who took 119 minutes to dive to 1,603 meters. Although they number in the thousands on land, they are mostly solitary in the water. Northern elephant seals are prey to great white sharks and killer whales. In late spring and early winter, northern elephant seals store large amounts of food as blubber in preparation for wintering on the ground.
Males fight to determine who is their lord. They don't kill each other, but they still fight until they are covered in wounds. When the males have secured their position, the females arrive and choose their own mates. They are polygamous, and one male will generally mate with 30 to 100 females. Males who fail in a fight will wander around the edge of the group and try to mate with females, but they will cause friction with males. A successful male can mate with more than 500 females in his lifetime, but most males never mate. A female can give birth to about 10 pups in her lifetime.
When the male reaches the shore, he will fast for about 3 months, and the female will fast for 5 weeks to mate and feed the pups. The gestation period is about 11 months. The peak of birth is from January 20 to February 1. Usually, the pups are born at night. The pups weigh 30 to 34 kilograms and are 127 centimeters long. The lactation period is about 1 month. The pups take about 4 weeks to feed, and then they will be weaned suddenly, and they can go to sea after two months. The female goes into estrus when she is weaned, and there are multiple females in the same male. Females reach sexual maturity at 3 years old. The subcutaneous fat is very thick, up to 87 mm, and a 4-meter-long male can produce 32.5 liters of oil.
Originally, there were a lot of northern elephant seals, but because of their large bodies and high oil production, they suffered a tragic death. Especially in the early 18th century, the development of the mechanical industry promoted the establishment of the oil refining industry. In order to grab the oil from the northern elephant seals, people hunted and killed them indiscriminately. By the 1760s, only 100 northern elephant seals remained, and they were on the verge of extinction. Since the Mexican government issued an absolute ban on the hunting of northern elephant seals in 1922, their number has increased slightly. By 1930, northern elephant seals reappeared in American waters, and the US government immediately protected them. In 1957, Mexico and the United States jointly established a safe zone of about 4 square kilometers for northern elephant seals. In the United States, they were protected in a more stringent manner, and their number eventually rose to more than 100,000.
The existing northern elephant seals have reached a population bottleneck and are vulnerable to disease and pollution. In California, the number of northern elephant seals increases by about 25% each year, and new populations emerge. However, their number is affected by the El Niño phenomenon and subsequent climate.
Protect wildlife and eliminate game.
Maintaining ecological balance is everyone's responsibility!