Seals are marine mammals that can be found in diverse climates throughout the world.
Although they are often associated with the polar regions, seals may live near tropical beaches and in more moderate climates.
With over thirty varieties, seals are highly intelligent mammals that can stay under water for up to two hours.
Some species have been trained for entertainment purposes and can be seen performing tricks in circuses.
Physical Appearance and Characteristics
Seals have unique physical characteristics.
Like other mammals, they are warm-blooded and nurse their young, but, unlike other mammals, have large flippers instead of arms or legs.
To withstand freezing temperatures, the seal’s body is covered in a slick, fur coat that is water-resistant and padded with layers of underfur.
Blubber or dense fat, comprises much of the seal’s thick, barrel-like physique.
Their flippers are large and make traveling on land awkward, but are ideal for swimming quickly through water and hunting for fish.
Seals have adapted to store large quantities of oxygen in their muscles, allowing them to stay under water for a much longer period of time than other mammals.
Diet and Hunting Methods
Seals eat small marine prey, including shellfish, squid, and fish.
Seals based in polar regions may eat penguins, seabirds, crab, krill, and other mollusks.
Some species may hunt the pups of smaller seals.
They are aggressive hunters and clutch their prey with their teeth, battering them against the ground until they are dead or, in the case of shell-fish, broken.
Social Structure and Communication
Seals live in complex social structures that may seem anarchic at first.
While they generally live in large groups with several hundred members, these groups are hierarchical.
Smaller groups of dominant males lead the pack and even smaller cliques of seals may form around particularly desirable females.
Traveling in large groups is a primary defense mechanism for seals, which are highly sought-after prey.
Mating and Reproduction
Like other mammals, seals compete with each other during mating seasons.
Male seals do not eat during mating season, which may last for up to ninety-days.
Similarly, when nursing, female seals do not eat and their bodies are sustained by fat reserves.
Dominant males may fight numerous, less aggressive males to access a female for mating and, depending on the species of seal, may establish a small group of females with whom to mate.
Seals that lose these battles may mate with females that are not already included in a dominant male’s group.
Female seals give birth to one pup at a time and are highly protective of their pups.
Interestingly, if a mother seal dies, the pups will not be taken in by other female seals and will be left to fend for themselves.
Habitat and Migration
Although many seals live in arctic regions, some may be found in tropical beaches throughout the world.
Global warming has had an adverse effect on seal populations and excessive blubber, which is commonly found on seals living in cold climates, becomes a maladaptive characteristic.
Excessive fishing has also impacted seals, who may migrate for hundreds of miles for access to crab, krill, shellfish, and other dietary staples.
Seals thrive where there are cold currents and their habitat of choice is dictated largely by this.
They live only in saltwater environments and prefer beaches.
Threats and Predators
While killer whale, sharks, and polar bears prey on seals, these natural predators are not seals’ greatest threat.
Humans pose a tremendous threat to seals.
First, as marine mammals that prey on shellfish, seals are adversely affected by commercial fishing.
Many seals get trapped in industrial trawls and others die from malnutrition.
Second, seals’ pelts are aggressively poached and used in luxury fur coats.
Seal populations are at risk of becoming endangered due to excessive poaching.
Last, recent oil spills have depleted shell-fish populations and resulted in the deaths of hundreds of seals.
Oil spills have a lasting, toxic effect on the ocean and impact all aspects of seals’ livelihood.