Pinnipeds are semi-marine mammals that can live on land as well as water. Walrus, Eared Seals (Sea-lion and fur seals), and Earless seals belong to the pinniped family. Unlike other mammals with hands, claws, and feet, pinnipeds have fins; this is the reason why they are known as pinniped which means finned-feet in Latin. These fins enable them to walk on land and swim under water. Their lustrous and barrel-shaped body has short, wide, and flat flippers on either side of the body. Pinnipeds have thermoregulations that keep them warm in cold areas. They rely on blubber or fat under their skin to preserve heat and energy. Some even have fur and blubber for the same purpose. Moreover, the fat blubber under their skin also gives them buoyancy to float on water. This process is for pinnipeds living in cold waters but the ones living in arid areas do a sand-flip to keep themselves cool. Read on the article to collect some interesting facts about pinnipeds.
Scientific Name: Phocavitulina
Shape: Barrel shaped
Diet: Carnivorous and eats aquatic creatures, like fishes, squid
Size: 1.3 m to 4 m
Weight: 70 kg to 4000 kg
Teeth: 34 to 38
Life Span: 20 to 35 years
Natural Habitat: Water and land
Call: Mumble, bawling, hissing, barking
Gestation Period: 8 to 15 months
Number of Offspring: 1 or 2
Interesting And Fun Facts About Pinniped
- Pinnipeds are believed to have evolved from bears and otters which are land animals.
- From all the species of pinnipeds, earless seals are the most diverse ones, which belong to the phocidae family.
- The seals belonging to the phocidae family are excellent divers and swimmers but they cannot walk. The tail-like back flippers don’t help them in walking on the surface. Earless seal is one of the species belonging to the phocidae family.
- Earless seals, like many species of owls, don’t have ears rather they have ear openings.
- The earless seals grunt or flap on water to communicate with the other seals and they don’t prefer making loud voices.
- Eared seals of the otariidae family are known as walking seals. These mammals have rear flippers that help them to stand and walk. Sea lions and fur seals also belong to the same category.
- Various genetic evidences have revealed that several fur seal species are more closely related to the sea lions and not the true seals, for instance, the ball-balancing fur seal, known asCaliforniasea lion, is related to sea lions.
- A large body with less fur differentiates lion seal from the fur seals.
- Walrus, another species of pinniped, are now the only surviving members of the odobenidae family.
- Walrus can be recognized from a long distance because of its tusk and wrinkles. The bulk of fat under its belly makes movement difficult and therefore it can be seen lying lazily on ice for hours.
- Walrus use their tusk to walk hence they are termed as ‘tooth-walking’ mammals. These tusks are also used to create holes in the ice and breathe under the sea covered with ice.
- Previously, walrus were included in the otariidae family along with the eared seals, but later the researchers identified their squirt and suck method of feeding on molluscks. This unique feature of a walrus differentiates it from other pinnipeds.
- Although walrus was differentiated from other pinniped lineages but the fact as to whether they were differentiated before or after the introduction of true seals still remains under suspicion.
- When it comes to reproduction, most of the species of pinnipeds; such as northern fur seal, South American sea lions, and elephant seals defend harems (specific category of female pinnipeds) while sea lion and brown fur seals defend another reproductive colony of other females.
- The reproductive behaviour of all the pinnipeds, except walrus can be easily recognized as walrus prefer to copulate in remote locations or under water.
- Due to the presence of postpartum estrus, the female pinniped can mate soon after giving birth.
- The lactation period is different for different species. Mothers belonging to phocid family feed the pup for 4 to 50 days while those belonging to the otariidae family spend 4 to 36 months feeding the pups.
- After the lactation period, the mother seal moves out to feed itself and on its return, the next task is to search for the pup out of the large group. But she can easily identify its baby from other similar looking pups by making a call that the baby replicates.
- The pups of seals enter the water instantly after birth.
- The largest pinniped is male southern elephant seal which weighs upto 4000 kg and can be 13 feet tall whereas Baikal seal is the smallest one that weighs 70kgs and is about 4 feet tall.
- Pinnipeds are found almost everywhere in the world, whether tropical areas or polar surroundings.
- In polar areas, pinnipeds stop their blood flow to the skin surface in order to prevent heat from escaping their bodies, while reverse action is performed in warm areas. They send blood towards the extremities in order to release heat from the body.
- Pinnipeds use their whiskers to find their prey as opposed to snouts used by other mammals. Their preys are usually squids, crabs, krill and, other marine animals.
- Pinnipeds have the ability to control their heart rate while diving; this is the reason why they are found to be sleeping in deep waters for extended period of time. A study shows that they can reduce their heart rate by 50-80%.
- They can dive up to 1700 feet deep under water in one go and can stay there up to 40 minutes.
- Killer whales, polar bears, and sharks are the major predators of pinnipeds.
- Harbour seals are the most easy to train and can be seen in water parks where they perform water shows. They are extremely friendly but still you need to be cautious.
- Fur seals or eared seals have very good hearing power, irrespective of the fact that their ears are small.
- The leopard seal is the only seal that eats penguins. It has also been known to be aggressive against humans and has attacked humans thrice, out of which one was fatal.
- Sea lions can run with a speed of 25-30 km per hour, faster than human. They might look like a crooked human while running.
- Ringed seals are larger in number as compared to all the arctic seals. There are approximately 2,00,000 ringed seals worldwide.
- The flippers of pinnipeds are shorter than any other mammal.
- The fur or hair present on the outer body of the fur seal act as water repellents while the underfur insulates it from the outside temperature. Along with this fur coat, they also have blubber to store fat, which can be used in case of food scarcity.
- The eye membrane protects their eyes under the water. This is the reason why pinnipeds can see below and above the surface.
- Pinnipeds can easily hear sounds under the water with the help of whiskers and sensors in their skull.
- They have strong resistance to accumulated lactic acid as compared to other mammals.
- These semi-aquatic animals can hold their breath for almost two hours underwater.
- Most of the species of pinnipeds go through the moulting process every year. During the period of moulting, they shed their fur coat or skin and replace it with the new one.
- The pups of fur seals are susceptible to hypothermia as they are not born with dense and insulated fur coat. During their first moult, they replace the thin layer on their skin with an adult coat.
- The pinnipeds living in polar regions rely on blubber and dense fur coat to preserve heat inside their body, while those living in areas with warmer climate keep themselves cool by resting in shade and hiding under the thin layer of sand.
- The lung system of pinnipeds has airways supported by cartilage, a flexible connective tissue; smooth muscle; and alveoli that completely collapse during deeper dives.
- A respiratory collapse is considered as a disease in humans but pinnipeds can easily reinflate their lungs in the case of lung overemptying. But how? It is possible because of the presence of surfactant system that acts as an anti-adhesive to cope up with the problem of respiratory collapse.