Learn some of the most useful seal facts for kids including seal diet, habitat, reproduction, and its physical behavior. The seal is a fin-footed mammal that is commonly referred to as pinnipeds. These animals are the diverse group of marine mammals that are considered to be semiaquatic species befalling under the family of Odobenidae. The seals are slender-bodied mammals that are perfectly adapted for the aquatic habitats where they spend their entire life. They can grow to a size of about 1.3 meters. The seals are believed to have appeared some 23 million years ago in the period of Miocene and Neogene. The first seal fossil discovered is Pijila darwini 23 million years ago. These animals are highly terrestrial mammals and are known to reside in deep waters, lakes, and streams. A good many number of these species were hunted down to the near extinction.
True Seal Facts
A seal laboriously humping across the ice, unable to raise itself by means of its foreflippers, is, moments later, plunging to 600 m (2,000 ft) and staying underwater for over an hour—true seals are wonderfully adapted to diving, but at the expense of agility at land. Although seals have physiology that makes them ideal for diving, they are still not wholly liberated from their otter-like ancestors of some 25 million years ago. One of the fundamental characteristics of these animals is that they tie to land and ice for birth and raising their young which ultimately defines the basic pattern of their lives.
Like otters, true seals are fully capable to swim with the help of their strong sideways movements of their hindquarters. This is not observed in eared seals. They have long wide-webbed feet which serve as effective flippers in water and not on land. Unlike eared seals, the forelimbs are not powerfully propulsive; they are affixed to the end of the hand and are employed for steering in the water and, sometimes, to help in scrambling on land or ice. The Antarctic seals have more active and long foreflippers in comparison to the northern true seals which have developed more strong arrangements of muscle connection along the spine.
For the reason that true seals need to spend long periods of time under water, the circulation and respiration are so adapted. One of the supreme divers is Weddell seals that dive in a depth of 600 meters (2,000 ft) under water.
There are around 18 extant species of true seals which are classified into two subfamilies. The Mediterranean and Hawaiian monk seals fall into the family of southern seal. These are all tropical species. The Caribbean monk seal is believed to become extinct. The Antarctic seals include Ross, Leopard, Weddell, Crabeater; and the southern and northern elephant seals.
Amazing Seal Facts For Kids
- In general, the seals have slender and barrel-shaped body.
- The seal bodies are perfectly adaptable for the aquatic habitats where they spend most of their time.
- These animals have short limbs with the length measuring at 1.3 meters (4 ft 3 in).
- The largest male seal ever recorded was southern elephant seal measuring at 4 meters (13 feet), with the weight around 4,000 kg (8,800 lb).
- The smallest seal is Baikal seal measuring at 70 kg (155 lb).
- There are earless seals that are also known as phocids and they lack external ears.
- These animals are regarded as efficient swimmers as they have rather more advanced flippers for doing so.
- The swimming efficiency and an array of other physiological adaptations make them better built for deep and long diving as well as long distance migration.
- When it comes to walking on land, the seals are rather clumsier.
- These mammals tend to communicate by beating water and grunting instead of producing traditional sounds.
- There eared seals that are known as sea lions or fur seals.
- One of the seal species is walrus that inhabits exclusively in Arctic region. With their long tusks, these animals can be easily documented and they weigh around 2,000 kg (4,400 lb).
- The walrus primarily relies on squid, fish, invertebrates, and mollusks for their diet.
- The most frequent seal predators include sharks and orcas. Apart from sharks, these animals are also regularly preyed upon by polar bears.
- The molting occurs annually and can bargain thermoregulation.
- These pinnipeds employ various methods to conserve body heat while hunting in water. The majority of these animals are reliant on dense layer of blubber underneath their skin.
- The females have postpartum estrus that enables them to mate right after giving birth.
- The lactation period for phocid ranges from 4 – 50 days.
- The seals are known to spend most of their time underwater so as to adapt themselves for sleeping in water.
- The smaller species such as Ringed seals and Caspian seals become mature at the later part of their lives as compared to the larger Antarctic species or the huge elephant seals. Although both males and females become fertile while they’re quite young, males cannot find their mates until they are much larger some years later.
- The females of Harp, Baikal, Harbor, Ringed, and elephant seals are known to mature quite earlier in populations limited by exploitation. Many females of a species are known to reproduce at about the same time, though populations at higher latitudes perhaps later. The Grey seals are somewhat unique in citing and timing of breeding sites.
- In the pack-ice seals the average lactation period lasts for 1 – 2 weeks, while in case of Baikal and Ringed seals the lactation period is up to 11 – 12 weeks. The Ringed and Baikal seals suckle their babies in the snow-caves on a fast ice. The difference seems to be associated with the protectiveness and stability of the nursery.
- The pups of Monk and Harbor seals on land and Weddell seals on fact ice begins are weaned in about 5 – 6 weeks after their birth; whereas the pups of Grey and elephant seals are weaned in about 3 – 4 weeks. The males of elephant and Grey seals will mate with as many females as it can.
- The pups of many species seem to undergo increase in their weight during lactation averaging about 2.5 – 3.5-fold. The pups of Baikal seals increases their weight to 5.5-fold, in a lactation period of 8 – 10 weeks.
- The fat content in the milk of harp seal female increases from 23% at the start of the lactation, to 40% when the lactation ends. The female does not eat anything during this period and the water content decreases. Pups are rarely adopted, and few male pups of Northern elephant seals may ask an unrelated nurse after being weaned usually, thereby adding unusual weight and, possibly, adult fitness.
- The gestation period lasts for 10 – 11 months.
- Many Grey seal species are known to patrol true territories of 260 sq. km (100 sq. miles), pushing other males and sometimes females, while on a Nova Scotia beach spaces occupied by males are overlapping and flexible (i.e. not territorial).
- Species that mate under water might be or might not be territorial, the fact is unknown. However, adult male Weddell seals actively defend their territories of water for up to 200 meters (650 feet). The individual Ringed seals may cover up to 1 km (0.6 mile). The male Harbor seals are also seem to be territorial species.
History of Seals | Seal Facts For Kids
Fossils have brought many evidences to the scientists such as the evolution and the spread of the true seals. According to these fossils, the true seals emerged in the North Atlantic region and it may be possible they have derived from otter-like ancestors in western Asia and Europe. Micocene fossils is the oldest mid-to-late fossils predating 12 – 15 million years ago of Europe and eastern USA and are assignable to the modern tropical and northern seal groups.
Apparently it seems as if monk seals have emerged in Mediterranean, where they also live today, and extend towards the Pacific throughout the Caribbean and the open (until 3.5 – 4 million years ago) Central American Seaway. Similarly, the ancestral elephant seal belonging to the same Atlantic tropical sea stock, entered Southern Hemisphere through the South American west coast, leaving behind more aboriginal northern species.
The study of fossils in Europe and eastern USA including South Africa, Peru, Argentina, indicates that the tropical ancestors of Antarctic seals invaded the Southern Ocean, eastern and western South America, along with the West Africa. The bearded seal though sometimes referred to as northern seals because of is bone structure, is associated with the tropical seals possibly due to its less-developed ear regions and the dark lanugo. The Hooded seal is not an elephant seal rather it is a true northern seal, maybe the relic of a more primitive ice-breeding group throughout the North Atlantic.
It goes without saying that many fossil seals deem to be ancestors of modern seals, there are some which are clearly not! Acrophoca longirostris is the most unique fossil discovered today in the Peru, and is linked to the Antarctic seals, but curiously long-snouted, like a dolphin. Unlike the eared seals of North Atlantic, the true seals did not seem to have undergone the bursts of evolution.
Where Do Seals Live | Seal Facts For Kids
The true seals are believed to have emerged in warm waters where monk seals survive today. Currently, they are living in the high latitudes of Southern and Northern Hemispheres. All of the northern seals breed on ice except Harbor seals which are known to breed as far south as Baja California (the Grey seal is often found breeding on ice and land). Of the southern seals, the northern and southern elephant seals breed respectively from California to Mexico and in the temperate to subantarctic parts of the Southern Ocean. The four Antarctic seals are known to breed on ice; generally these seals are found in the South of the Antarctic Convergence at 50o – 60o.
One of the prominent differences between species is the size and the relative sizes of the genders. There are certain Ringed seals that weigh no less than 50 kg (110 lb); on the contrary adult Southern elephant seals may be 50 times heavier. Generally speaking, most male and female species are similar in size.
In certain species, females are larger than males such as in the southern seals especially the monk seals, Weddell seals, and the Leopard seals; however, males of northern seals—the elephant seals, the Grey and Hooded seals—are much larger as compared to females; besides, these large males also display arched, heavy skulls and nasal protuberances for aggressive show. Mostly, the size difference is observed in the Southern elephant seal, in which the male is three times heavier than the females.
These animals are exclusively carnivorous as they predominantly feed on squid, shellfish, fish, and marine animals. There are few species that are known to take on squid such as southern elephant seals and Ross seals. Crabeater seals are known to consume ringed seals, crustaceans, and krill. Certain seals prey on warm-blooded prey including other seals. The South American sea lions prey on penguins and flying seabirds. The stellar sea lions take on common seal pups and birds.
Due to its aquatic life, seals have to rely on small and softs food. This explains why they have rows of five uniform teeth instead of cutting-and-crushing molars which are found in the terrestrial carnivores. Many seal species are, however, opportunistic and they have a specialized diet.
Although many species are found living in the same region, they seem to have some differentiation too. In the Bering and Okhotsk seas the Ringed seals, for instance, breeds on a heavy pack ice or land-fast ice and feed on planktonic crustaceans with small fish; whereas the Ribbon and Spotted seals use fairly light ice-pack and thus feed on deep-water squids and fish as well as shallow-water fishes. The Bearded seal is another species that lives in this area, and is mainly feed on bottom-dwelling shrimps and mollusks; its teeth are worn quite early in life.
The Weddell seals feed on fishes around the fast ice in Antarctica, while the Ross seals primarily rely on deep-water squids; similarly, the leopard seals eat penguins and other seals; the Crabeater seal is very fond of eating krill which it stains through its mainly sharped teeth.