Elephant Seal

The Elephant seals are the large, ocean-going earless seals of the genus Mirounga. The Northern elephant seal and the southern elephant seal are the two species of the Elephant seal. The northern elephant seal’s scientific name is Mirounga angustirostris and the southern elephant seal’s scientific name is Mirounga leonina. By the end of the 19th century, elephant seals were hunted until the brink of extinction but as they say, time heals everything, as time passed the numbers of elephant seals have gradually increased and improved. The elephant seals are regarded as the largest extant carnivorous which weighs up to four thousand kilograms. 

The northern elephant seal, somewhat smaller than its southern relative, ranges over the Pacific coast of the U.S., Canada, and Mexico. Race Rocks, on the southern point of Vancouver Island in the Strait of Juan de Fuca, is the most northerly nesting site on the Pacific Coast. The southern elephant seal may be found on islands like South Georgia and Macquarie Island in the Southern Hemisphere, as well as on the coastlines of New Zealand, South Africa, and Argentina on the Peninsula Valdés. At Jackson Bay, Admiralty Sound, Tierra del Fuego, in southern Chile, there is a small colony of 120 animals.

Fragmentary remains of an unknown member of the tribe Miroungini reported from the late Pliocene Petane Formation of New Zealand are the oldest known unequivocal elephant seal fossils. It is believed that the elephant seal evolved in the Pacific Ocean during the Pliocene period. Elephant seals are known to breed annually and are very faithful to the colonies that have established breeding areas.

In this article, we are going to discuss the elephant seal, Its habitat, description, elephant seal size, elephant seal weight, reproduction, life cycle, threats and predators, and also a few of the most important and frequently asked questions related to elephant seals will be answered. 

Physical Description of the Elephant Seal 

• Elephant seals are the marine mammals that are classified under the order Pinnipedia which means feather or fin-footed in Latin. The elephant seal falls under the family of Phocidae and they are considered as the true seals.

• True seals, also known as phocids, lack an external ear and have short limbs. Their limbs have been reduced, allowing them to be more streamlined and glide more readily in the water. However, because they can't bend their hind flippers forward to walk like Otariids, it makes travelling on land more challenging.

• The elephant seals have a hand flipper and in addition to it, they also have a lot of surface area which helps them to propel or push water so that they can swim properly. About 90% of life is known to be spent underwater in the sea by the elephant seals in the search of food. It has been estimated that they can cover up to 100 kilometres a day in the water in search of food. 

• A newborn elephant seal weight would be around 36 kilograms and an elephant seal size can be 122 cm in length. The sexual dimorphism seen in the elephant seal is extraordinary as the male elephant seals weigh 10 times more than the females and have a prominent proboscis. 

• Elephant seals get their name from the mature male's enormous proboscis, which resembles an elephant's trunk and is considered a secondary sexual feature. The proboscis of a bull is utilized to make extremely loud roaring noises, especially during mating season. More significantly, the nose functions as a type of rebreather, with chambers intended to collect moisture from exhalations. This is especially crucial during the mating season when the seals are unable to leave the beach to eat and must preserve body moisture due to the lack of an incoming water source.

• The colouring of northern elephant seals is typically brown, however, there are some variances. Males are often a deeper brown, while females are typically a light tan. Hair loss occurs in both adult males and females, and hair is totally gone for a brief period following molting. Newborns have black hair until they are properly weaned, at which point they shed their black coats and are replaced with lighter ones. All adults and newly weaned juveniles have countershading, which shows a darker hue dorsally and a lighter colour ventrally. Their hind flippers are lobed, and they have two of them. Because the pinnae are missing, the ear appears to be flush with the skin.

• The enlarged proboscis that graces a man's face is the most noticeable characteristic of his body. Females lack this characteristic, and it is greater than their somewhat larger related cousins, southern elephant seals. The proboscis begins to develop in young males at the age of two, but it does not fully mature until the animal is eight years old. These animals are among the biggest in the Northern Hemisphere's group of aquatic carnivores.

• A female elephant seal weighs between 600 to 900 kilograms and males as mentioned before are known to be 10 times larger than that of the females. 

• A female elephant seal size or can reach a length of about 4 centimetres on average and the males generally extend from 5 centimetres. 

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Physiology of Elephant Seals 

• Elephant seals are known to spend about 90% of their lives in the sea. The elephant seals are known to keep their breath held in the water for more than 100 minutes which is longer than any non-cetacean mammal. The elephant seals dive up to 1600 metres beneath the ocean surface they dive deep into the ocean in search of some of their favourite foods which include skates, rays, squids, eels, octopuses, and small sharks. Gastroliths are also common in their stomachs. Between dives, they just spend a few moments at the surface to rest. Due to their prey supply, females dive a little deeper.

• Elephant seals' fat protects them from the cold more than their fur. In huge areas, their hair and exterior layers of skin moult. Blood vessels that extend through the blubber must re-grow the skin. When a seal moults, it becomes vulnerable to the cold and must rest on land in a protected area known as a "haul out." Northern males and young adults molt between June and July and the northern females and juvenile seals moult between April and May.

• Elephant seals have a big blood volume, which allows them to store a significant quantity of oxygen for diving. They have huge sinuses in their abdomens to retain blood, and they can also store oxygen in their muscles thanks to higher myoglobin concentrations. They also have a higher percentage of oxygen-carrying red blood cells. Elephant seals can dive to such depths and stay underwater for up to two hours because of their adaptations.

• Elephant seals have the ability to slow down the heartbeat and even divert blood flow from the external areas of their body to important organs. They are also known to slow down their metabolism while performing deep dives. 

• Elephant seals have a countercurrent heat exchanger in their body that helps them preserve energy and avoid heat loss. The arteries and veins in this system are organized in such a way that cool blood flowing to the heart is warmed by blood flowing to the animal's external areas, allowing the body to maintain a constant temperature. The milk produced by the female elephant seals is known to be very rich in milk fat when compared to that of other animals. It increases to above 50% milkfat after beginning at a lesser level.

Geographic Range and Habitat of the Elephant Seal 

• The elephant seals may be found in the Pacific Ocean's coastal waters from the Gulf of Alaska to Baja California. Males and females make independent foraging excursions two times a year. Males travel to the Aleutian Islands and the Gulf of Alaska in the north. Females do not move as far north as males, preferring to migrate west to a more open ocean. 

• The total linear distance travelled by the elephant seal each year is estimated to be around twenty-one thousand kilometres. Seals are most frequently observed onshore from December to March when they are mating, then again beginning in April and lasting through August, when they are hauling out for moulting.

• The elephant seals live on land, mainly on outlying islands, on the sandy, rocky, or muddy beaches of the coast. When they're on land, they usually congregate in big groups. During reproduction and moulting, the elephant seals spend just 10% of their time on land. The remaining 90% of the time is spent in the water, diving, and hunting for food, with just 11% of the time spent at the surface. This means they spend an incredible 85-90 percent of their time at sea or underwater. The elephant seals can dive to depths of up to 600 meters on average and have been known to stay at depths of over 1500 meters for lengthy periods of time.

Behaviour of Elephant Seals

• The elephant seals are considered to be solitary in nature when they are in the water but they do come together during the mating season on the shore. They are known to be not stagnant throughout their lives as they migrate while foraging the food and also while mating. 

• During mating season, there is a social order, but when the males haul out for moulting, they are less hostile against one another. During foraging migrations, one of these creatures' most remarkable characteristics is their diving habit. The capacity of these creatures to stay underwater for long periods of time is not due to their ability to hold their breath. Before diving, these seals expel air from their lungs, and the oxygen they require is acquired from their blood and tissues for the 20 to 70 minutes they are underwater.

• The elephant seals are known to possess blood that is rich in haemoglobin and tissues that are rich in myoglobin and hence that is the reason that these creatures have an increased oxygen storing ability. 

• The absence of rest or sleep for such a long length of time is another characteristic of this diving behaviour that has confused experts. The elephant seals have been observed diving 24 hours a day, sometimes for months at a time, according to recordings. Because the seals' metabolic rate is so low, it's assumed that the diving action is a sort of slumber for them.

Feeding Habit of Elephant Seals

• Elephant seals spend 90% of their time in the water to eat. They dive into the water repeatedly and constantly to hunt food during their foraging excursions, never resting to rest or sleep for months at a time. Females and males have distinct feeding areas. Male elephant seals migrate north, staying closer to land, and feeding in the same places year after year. Females travel west to the open ocean, away from the shore, and are less consistent in returning to the same locations year after year.

• The foraging activity of male Elephant seals is characterized by benthic dives to the bottom. Females, on the other hand, engage in pelagic diving when foraging, which involves a trip to the bottom, a partial ascent, another trip to the bottom, a half rise, and so on. There is some debate as to why male size is so disproportionately large in comparison to female size, and some theories claim that dietary type may be a role.

• Males are more inclined to consume densely packed meals such as sharks and skates, whilst females choose less dense things such as squid. These dietary variations are most likely due to the various locations where they are foraging. Differences in body size are believed to be the cause of resource partitioning. Males are less susceptible to predators, therefore foraging in regions with more predators is safer for them. Females are more susceptible to predators, therefore they must graze in less predator-infested regions. Elephant seals are fasting when they are on land. They go without food for long periods of time when reproducing and moulting. During this stage, all nourishment and energy are derived from fat that has been deposited as blubber on their bodies. These creatures are thought to never drink water. Water is obtained from food and lipids that have been broken down. They've also devised physiological techniques for retaining water, such as creating concentrated urine. Another fascinating feature of these creatures is their proclivity for chewing stones before coming ashore. The real motivation for this practice is unknown. The stones then are eliminated when they enter the water for migration and a few of the people also suggest that this phenomenon is done as a response to the long period of fasting. 

Reproduction and Mating Practices in Elephant Seals 

• The mating habits of the elephant seals which are also marine mammals have been considered to be one of the most spectacular visuals, the elephant seals reproduce during the winter season. Every year grown-up male and female elephant seals will migrate back to the beaches where they were born and during reproduction, these beaches are called rookeries.

• The males are the first to arrive, pulling themselves out on the beaches and claiming territory. The "alpha" males are the adult males with proboscis and cornified chests who build the best and biggest territory.

• The alpha males may easily split out early in the season, but as the season develops, there is seldom enough area on the beach for all of the adult males, and combat ensues to establish the strongest alpha males as the "beach rulers."

• Threats, vocalizations, and lunging are used by elephant seal males to establish their territory. When a male lifts his front flippers, he is posing a threat. The next step is to vocalize into the proboscis. Subordinate males will instantly lie down, establishing a hierarchy. If two alpha males are in the same area and do not move apart in response to vocalized threats, they will fight physically by lunging at each other, shielded by their cornified chests. This may result in bloodshed, but it rarely causes serious physical harm. One animal will eventually give up, lie down, and leave the "winner's" area.

• The alpha males are scattered over the beach after about a month and are now known as a rookery based on their capacity to preserve their territory. Subadult guys are allowed on the beach if they remain submissive and lie down. Weaker males are driven to the rookery's outskirts.

• The alpha males bring the juvenile males along, and they practice fighting in simulated fights. These practice flights are typically short and do not result in any injuries. These males lack a fully developed proboscis and a cornified chest.

• As the territories take shape, the females begin to arrive. Some arrive during the war, but the majority arrive after the regions have been formed. When an alpha male's territory is established and females begin to arrive, he will not leave the beach, even to eat. A powerful alpha male may have a harem of a dozen or more females surrounding him during the breeding season, with whom he will mate. The females will stay on the seashore with their youngster for three to five weeks after giving birth.

• Elephant seal babies are born on the sand. The pregnant women are basically laying around in their harems, so there is little warning of birth. The first sign of new birth is generally a flock of seagulls flying to the new arrival and devouring the afterbirth. Newborn puppies may be recognized from older puppies not only by their smaller size but also by the presence of fetal folds, which are wrinkles down their sides caused by being coiled up in their mother's womb. The majority of puppies are born over the course of a week or two, although some are born earlier in the season.

• After their birth, puppies will feed for three to five weeks. Elephant seals produce exceptionally rich milk, and their young gain weight on a regular basis. The milk is thick, which is almost pudding-like.

• The babies that have been abandoned on the seashore are extremely overweight. They're known as "weaners" and can spend up to a month on the beach before becoming hungry. All of the adults leave after the conclusion of the reproductive season, which begins with the entrance of the males and lasts around two months, leaving just the weaners on the beach. The weaners then go to the sea to eat, leaving the beach deserted until the animals molt the following summer.

Conservation Status of Elephant Seals 

• The elephant seals are very important as predators on the squid’s octopus, small shark skates, and fish. By feeding on creatures these animals impact the population of the above-mentioned animals. The elephant seals are considered to be very important as food for animals that prey on them such as the great white sharks and the Orcas. 

• Elephant seals are not currently threatened. However, it was once assumed that this species had been hunted to extinction. After being abused by hunters and whalers attempting to use the animals' thick coating of blubber as an oil source, they were thought to be extinct by the 1880s. In 1892, a few creatures were discovered, and they were trapped and slaughtered for scientific research. It was eventually determined that a population of 20 to 100 people had survived. According to studies, every single person in the current population of over 175,000 is a relative of these few survivors.