What Eats Seals? A Detailed Look At Seal Predators

Seals spend much of their time in the water, but what threats lurk below and above waiting to make a meal out of these aquatic mammals? If you’re short on time, here’s a quick answer: polar bears and orcas are the main predators of seals in the wild.

In this nearly 3,000 word guide, we will provide a comprehensive overview of the natural predators of seals both in the water and on land. Read on to learn more about shark species, bears, killer whales, and other animals that eat seals as part of their diet.

Predators of Seals in the Water

Orcas

Orcas, also known as killer whales, are one of the main predators of seals in the ocean. As highly intelligent and social apex predators, orcas hunt in coordinated pods to take down their prey. They use sophisticated hunting techniques like wave-washing, where they create waves to knock seals off ice floes.

Orcas are powerful hunters and even attack large whales. They can reach speeds up to 30 mph in short bursts to catch seals.

Some key facts about orcas hunting seals:

• Orcas prey on elephant seals, leopard seals, fur seals, and harbor seals.
• An orca pod can coordinate to create waves to knock 300-400 kg seals off ice into the water.
• Orcas slam their bodies against ice floes to create a wave that washes seals into the water.
• They are intelligent hunters and even seem to use tools by manipulating bait balls of fish to draw seals within range.

Orcas are such effective seal hunters that some seal populations have developed defensive strategies. Harbor seals will detect orca calls and quickly flee to the safety of shore. Penguin colonies also react to the presence of hunting orca pods by clustering together or quickly exiting the water.

Sharks

Sharks are another major ocean predator of seals. Species like great white sharks, tiger sharks, and bull sharks all prey on seals. Their speed, size, and razor-sharp teeth make them formidable hunters.

Here are some key facts about how sharks hunt seals:

• Great white sharks reach speeds over 15 mph and can launch out of the water to snag basking seals.
• Tiger sharks and bull sharks patrol shallow waters looking for seals. They are less specialized hunters but still dangerous.
• Sharks rely on stealth and surprise attacks, waiting to strike seals from below.
• Some sharks like great whites have around 300 serrated teeth ideal for gripping slippery seals.
• Seals must be vigilant of lurking sharks when entering or exiting the water from land/ice.

Seals have adopted strategies to reduce the risk of shark attacks, such as avoiding areas frequented by sharks and not staying too long in shark hotspots. Still, sharks account for significant seal mortalities each year.

Fish

While sharks and orcas are the most feared ocean predators, some large predatory fish also pose a threat to seals. Species like barracudas, tuna, swordfish, and marlin all prey on seals. Though these fish are not as well equipped to hunt seals as sharks and orcas, they still represent another predation pressure in the challenging marine environment.

Here are some key facts about how predatory fish attack seals:

• Barracudas use speed and surprise to ambush seals from below or the side.
• Swordfish and marlin slash at seals with their sword-like noses.
• Tuna rush at seals in coordinated groups like wolf packs.
• Some fish may bite at seals or remove chunks of flesh in repeated attacks.
• Seals are most vulnerable to fish attacks when they are young pups still developing swimming skills.

In the dangerous waters they inhabit, seals must remain constantly vigilant to avoid predation from below by fish. By swimming in groups, seals can better watch for predators and mount group defense against attacks.

Predators of Seals on Land

Polar Bears

Polar bears are the top predators of seals on land, especially ringed seals and bearded seals which make up a large part of their diet. Research shows that polar bears rely on seals for up to two-thirds of their energy requirements (Polar Bears International).

Their powerful jaws and sharp teeth make them well-equipped to hunt seals. Polar bears often wait patiently by seal breathing holes in the ice to ambush them, grabbing them with their large front paws as they surface.

With declining Arctic sea ice due to climate change, polar bears are having more difficulty hunting seals which could threaten this predator-prey relationship (Canadian Geographic).

Brown Bears

Though their main diet consists of vegetation and salmon, brown bears do opportunistically prey on seals along coastlines and rivers during certain times of the year. harbour seals and northern elephant seals are vulnerable when molting or giving birth.

The large Kodiak brown bears are especially efficient seal hunters, using their keen sense of smell to detect seal dens and digging out the pups with their long claws. Researchers found remains of seals at up to 65% of brown bear feeding sites on Kodiak Island, Alaska (Journal of Mammalogy).

So while seals only make up a seasonal supplement, brown bears can significantly impact seal populations in some regions.

Other Land Predators

Wolverines, foxes, wolves, and even ravens are known to opportunistically prey on seal pups left unattended on land. One fascinating strategy is that of orcas working cooperatively with wolves to hunt seals.

While rare, there are documented accounts of orcas intentionally beaching themselves to grab seals, giving wolves the chance to scavenge any leftovers (Alaska Department of Fish and Game). Additionally, leopard seals – though normally aquatic hunters – will sometimes seize seal pups on land as well.

So while these predators pose little threat to adult seals, taking unattended pups can shape seal behavior, adaptations, and populations over time.

Predation Strategies Used Against Seals

Hunting in Groups

Many predators leverage the power of the pack when hunting seals, increasing efficiency and taking down larger prey. Killer whales, also known as orcas, are adept at group strategy. Pods of orcas will intentionally beach themselves momentarily to grab seals on shorelines or coordinate movements in open water.

Leopard seals often forage with others, working together to isolate prey by circling and cornering lone seals. Estimates show 80% of leopard seal predation involves pack-based efforts.

Ambush Tactics

Sharks rely on ambush tactics and naturally-concealing water for stealthy attacks on seals. Great white sharks may vertically breach on hauled out seals from below or attack from depths as prey swim above. Bull sharks surprise seals in the shallow waters of estuaries and rivers.

Polar bears patiently wait at seal breathing holes in frozen Arctic ice for the opportunity to grab them by surprise.

Stealth Approaches

Stalk-and-kill strategies requiring stealth and surprise are also used by some seal predators. The Arctic fox is a cunning small land predator that creeps upwind to pounce on basking seals. Male South American fur seals will quietly enter breeding colonies and snatch vulnerable seal pups learning to swim.

Bald eagles glide in with muffled wing beats behind rocky cover to snatch unaware seal pups.

How Seals Try to Avoid Predation

Hauling Out in Large Groups

Seals often gather together in large groups called herds or harems when they come on land to rest, named “hauling out”. Hauling out in numbers is one of the main strategies seals use to avoid predators like killer whales and sharks.

Being in a large herd helps dilute an individual seal’s chance of being targeted, and there are more eyes to keep watch for threats (1).

Some key facts about seal herds:

• Harp seal herds can number in the hundreds of thousands on pack ice haul-out sites (2)
• Elephant seal harems contain on average 100-500 seals, dominated by a single large alpha male (3)
• Seals vocalize to each other in herds using calls and rhythmical claps to coordinate as a group (4)

Hiding Under Ice

Another protective strategy seals use is to take refuge under solid pack ice, away from open waters where large predators hunt. Species like harp and ringed seals use their sharp claws to maintain breathing holes in ice sheets.

They remain hidden in these small openings, safely out of reach from predators below the surface. Bears may wait silently at these holes to ambush the seals when they come up for air, but it is still safer than venturing into open waters.

Aggressive Defense

Despite their cute and cuddly appearance, seals can be quite aggressive in defending themselves from predators. Male elephant seals for example engage in violent battles using their teeth against rival males during breeding seasons (5).

When threatened, seals will use similar biting tactics against predators when hauled out. Species like leopard and gray seals also have a powerful crushing bite force that can cause serious injury (6).

In water, seals rely more on speed and evasion to escape predators. But they have been known to turn and attack much larger animals in coordinated groups if they have to. Pinning predators like sharks against the sea floor and mobbing them is an effective strategy seals use collaboratively (7).

Conclusion

In conclusion, seals face threats from a variety of predator species including orcas, sharks, polar bears, and other predators. These animals have evolved different strategies to hunt the seals, while the seals themselves have defense mechanisms to avoid becoming a meal.

Understanding the constant battle for survival seals face can give us a deeper appreciation of the challenges they encounter as prey species in the wild.