At first glance, their large bodies and short fins appear to make seals easy targets for predators and others that would compete for food and territory. However, these marine mammals are far from defenseless. If possible, a seal will usually use flight as a defense rather than fight.

Part of the seal's defense is in the difficulty of injuring a seal. With several inches of blubber, it takes a much larger animal to bite a seal and eat it. Except for animals such as killer whales and large sharks, most predators do not bother trying to capture a seal.

The ability to live in the water and on land is also part of their defense. When in the water, the streamlined body of the seal allows it to out maneuver predators and quickly jump on land to fully escape the water-bound predator.

As a last resort when grabbed by a predator, seals will bite and thrash to defend themselves. In the case of male seals, such as elephant seals protecting a territory from competing males, the two will battle by biting and slamming their necks against each other.