Are Sea Lions Dangerous to Humans? Bites and Safe Distance

How dangerous are sea lions really?

Compared with many wild animals, sea lions pose a low risk. The California sea lion, the species most people meet in North America, spends much of its life close to busy harbors and beaches, and millions of visitors watch sea lions every year without problems. On their breeding islands, California sea lions are actually skittish and often rush into the water when they see or smell people.

The risk comes from size and teeth. An adult male California sea lion averages about 275 kg (600 lb) and can reach about 390 kg (860 lb), and all sea lions have strong jaws and long, pointed canine teeth for catching fish and squid. On land they can move faster than many people expect, because they walk and gallop on all four flippers. A bite can cause deep puncture wounds, and bites from marine mammals can easily become infected.

Why do sea lions bite people?

Most bites have a clear cause:

• People get too close. A sea lion that feels trapped, for example between a person and the water, may lunge or bite to defend itself.
• Feeding. Sea lions that are fed learn to approach people and can grab at hands, food, bags or even clothing.
• Breeding season. Large males defend territories from about May to August and may charge anything that comes near.
• Mothers and pups. A female may defend her pup if someone approaches it.
• Illness. Sea lions poisoned by domoic acid, a toxin from algal blooms, can become disoriented and behave unpredictably.

Sea lions usually give warnings first. Barking at you, swinging the head from side to side, opening the mouth wide, staring or making short lunges all mean “back off”. The meaning of these sounds is explained in Why do sea lions bark?

Documented sea lion incidents

Serious incidents are rare enough to make the news. Some examples:

• Steveston, British Columbia, 2017. On a fishing wharf in Richmond, near Vancouver, a male sea lion that people had been feeding grabbed a young girl sitting on the edge of the dock by her dress and pulled her into the water. A family member jumped in and pulled her out, and she was treated for a minor wound. Experts thought the animal had mistaken the dress for food.
• San Francisco, 2017. In December, several swimmers were bitten at Aquatic Park Cove within about a week, apparently by a sea lion, and the National Park Service briefly closed the cove to swimming. Officials thought a single animal was probably responsible, since such bites are very unusual there.
• Southern California, 2023. During a severe domoic acid outbreak, many poisoned sea lions came ashore. In Orange County, a boy wading at Salt Creek Beach was bitten and another person was hurt at Strands Beach, which was briefly closed. Los Angeles County lifeguards urged beachgoers to keep well away from sea lions.

In each case, the trigger was the kind of situation described above: feeding, close contact in the water, or sick animals.

Why feeding sea lions is harmful

Feeding sea lions may seem kind, but it causes harm to both animals and people. In the United States, feeding or trying to feed wild marine mammals is illegal under the Marine Mammal Protection Act. NOAA explains that it changes sea lions’ natural behavior: they lose their wariness, learn to associate people and boats with easy meals, and begin taking bait and catches directly from fishing gear.

Fed sea lions are more likely to approach and bite people, and they are also more likely to be hurt, by swallowing hooks and lines, by being struck by boats, or by angry fishers. The safest rule is simple: never offer food, and never throw fish scraps into the water near sea lions.

How close is too close?

NOAA asks people to watch seals and sea lions from at least 50 yards (46 m), about half a football field, and to limit viewing to 30 minutes. Binoculars or a zoom lens give a good view from that distance. Other useful rules:

• Never get between a sea lion and the water, or between a mother and her pup.
• Do not touch, chase or try to move a sea lion, and keep children and dogs close.
• Do not sit with your legs dangling over the edge of docks where sea lions gather.
• If a sea lion lifts its head, barks at you or starts moving toward you, back away slowly.

A pup alone on a beach is usually waiting for its mother to return from feeding. It should be left alone and reported to a local marine mammal stranding network if it looks sick or injured. A similar situation with seal pups is explained in Is a seal pup alone on the beach abandoned?

What about sea lions in the water?

In the water, sea lions are fast, agile and often curious. Young sea lions sometimes swim up to divers and snorkelers, blow bubbles or mouth fins and equipment. In places such as Mexico’s Gulf of California, guided snorkeling with sea lions is popular and generally safe when guides keep groups away from territorial males.

Problems arise when people try to touch or feed them, or when a large male decides that a swimmer has entered his territory. Swimmers in harbors and coves should avoid sea lions they see in the water and leave calmly if one keeps following or nipping.

Where to watch sea lions safely

Some of the best places to watch sea lions are designed for it. At Pier 39 in San Francisco, sea lions rest on floating docks next to the pier, and people watch from railings without disturbing them; its story is told in Why are there sea lions at Pier 39? Many harbors and beaches along the West Coast, such as La Jolla Cove, Monterey and Morro Bay, also have places where sea lions can be seen from a respectful distance.

If anyone is bitten by a sea lion, seek emergency medical help immediately: call 911 (US), 112 (EU) or 999 (UK).