Seals and sea lions seem similar at first glance, but they have some key differences when it comes to behavior and aggression levels. If you’ve ever wondered whether seals or their sea-faring cousins are more likely to get nasty, read on to learn what makes each species tick.
If you’re short on time, here’s the quick answer: Sea lions tend to be more aggressive than true seals. Male sea lions compete fiercely for territory and females during breeding season. While seals can deliver nasty bites, they tend to be more timid and choose to flee rather than fight.
Basic Biology and Behavior
Seal Traits and Habits
Seals are semi-aquatic marine mammals that belong to the scientific order Pinnipedia. There are 19 species of true seals, including harbor seals, leopard seals, and elephant seals. Seals have streamlined bodies and flippers for swimming, and most species have short fur coats that help regulate body temperature.
Some key traits and habits of seals include:
- Spend much of their life in the water, but haul out onto land or ice to rest, give birth, molt, and escape predators
- Can dive to great depths – elephant seals have been recorded diving over 5,000 feet (1,500 m) to forage
- Migrate long distances to find food or reach breeding areas
- Generally less social than sea lions, often leading a more solitary life outside of mating season
- Use their sharp teeth and powerful jaws to catch fish, squid, crustaceans, and other marine prey
- Threats from human activity, pollution, habitat loss, and predators like killer whales are causing some seal populations to decline
Sea Lion Traits and Habits
Sea lions belong to a suborder called Otariidae, which includes 14 species such as California sea lions, Steller sea lions, and Australian sea lions. Unlike true seals, sea lions have external ear flaps and are able to “walk” on land by rotating their hind flippers forward.
Some behaviors and characteristics unique to sea lions include:
- More social than seals – they congregate in large groups and communicate with one another through barking and roaring
- Often breed in crowded rookeries full of competing males defending territories
- Can be taught complex tasks and trained to perform in aquariums or marine parks
- Migrate less extensively than seals, usually remaining closer to coastal areas and islands
- Dive shallower and for shorter time periods than seals – typically less than 1,000 feet for around 15 minutes
- Use their long fore-flippers for steering and propulsion in the water
- Threats from overfishing, pollution, oil spills and habitat disturbance have led to population declines
Researchers have discovered through observation and tagging studies that seals tend to be more solitary and dive deeper than the more social and coastal-oriented sea lions. However, both groups play critical roles in marine ecosystems and face similar conservation threats from human activity in their ocean environments.
Breeding and Territorial Behaviors
Seal Mating and Habitats
Seals tend to be solitary animals for most of the year, gathering in large groups mainly during the breeding season to establish territories and find mates. Different seal species prefer specific habitats – harbor seals enjoy coastal waters and haul out on beaches, rocks or sandbanks to rest and breed; grey seals populate rocky coastlines and islands; and elephant seals migrate long distances from rookeries on offshore islands according to NOAA studies.
During breeding season, dominant male seals stake claim to territory in areas with good haul-out sites. Females congregate in these territories to give birth and mate with the resident males. Male seals can be quite aggressive in defending their harem of females from challenging males.
Actual mating is fairly brief in most species. Northern fur seals for example only remain with females for a day or two. Scientists from the Australian Academy of Science report that females rather than males initiate mating.
Sea Lion Mating and Habitats
Sea lions are much more social than true seals. They gather in large breeding colonies and congregate on beaches, docks, buoys and rocky islands often in close proximity to human activities. According to NOAA biologists, California sea lions breed mainly on offshore islands of southern California like the Channel Islands and islands off Baja Mexico.
Adult bulls establish territory that females pass through seasonally. The bulls will try to herd as many females as they can into their area to mate with. They use threat displays, vocalizations and even physical conflict with other males to protect their territory.
Actual mating is very brief, after which the bulls continue seeking other females to add to their mating count. This territorial behavior leads to intensive competition between breeding males during peak season.
Interactions with Humans
Seal Encounters
Seals tend to be more wary of humans than sea lions. When seals haul out on beaches, they typically keep their distance from people. However, if approached or cornered, seals may bite or charge as a defensive reaction.
Male seals can be quite aggressive during the breeding season, so it’s important to give them plenty of space.
In general, seals pose little direct threat to humans. However, they can transmit diseases and parasites, so getting too close or interacting with wild seals is not recommended. Feeding seals should also be avoided, as this can lead to disruptive begging behavior and dependency on humans for food sources.
Sea Lion Encounters
In contrast to seals, sea lions tend to be more curious and playful around humans. They are highly social and often gather in large numbers on beaches and docks popular with people. While sea lions rarely attack humans deliberately, their size, speed, and powerful jaws mean they can inflict serious bites if provoked.
Male sea lions competing for mates and territory during breeding season are considered the most dangerous. They will bark loudly, charge, and bite humans that get too close. Even outside of breeding seasons, the huge bull sea lions should not be closely approached.
In areas like Galapagos Islands and Australia where tourists commonly encounter sea lions, attacks are very rare. However, feeding sea lions is problematic, as it causes them to lose their natural wariness of people and see humans as a food source.
This can lead to aggressive behavior when expecting food.
Ultimately, while seals and sea lions pose little threat if given space, both are still wild animals that can be unpredictable if approached carelessly. Caution and common sense is advised around these marine mammals to ensure safe and enjoyable encounters for both humans and animals.
Which Species is More Aggressive?
When it comes to seals and sea lions, both species can display aggressive behaviors at times. However, there are some key differences between seals and sea lions that impact their potential aggression levels.
Seals Tend to be More Solitary
Seals generally prefer to live alone or in small groups, congregating in large groups only during mating season. Their solitary nature means they tend to avoid conflict when possible. Seals display aggression mainly when defending themselves, their territory, or their pups. Otherwise, they tend to flee from threats rather than attack.
Sea Lions are More Social
In contrast, sea lions live together in large, complex social groups called rookeries. Living in close quarters with limited space can lead to more frequent conflicts. Sea lions will bite and push one another when competing for preferred resting spots on crowded beaches and docks.
Dominant males also fight fiercely to establish and defend their territories during breeding season.
| Seals | Sea Lions |
|---|---|
| Live alone or in small groups | Live in large social groups |
| Display aggression mainly when defending themselves/territory/pups | More frequent aggression due to crowding and breeding competition |
Biting Statistics
When it comes to aggressive interactions with humans, data shows sea lions are more likely to bite. According to researchers at the University of British Columbia sea lion bites have risen sharply in recent years as their populations grow and they get accustomed to humans who feed them fish.
Conversely, seal bites are quite rare. NOAA reports only 31 seal bites on humans that required medical treatment between 1991-2011, compared to over 1,500 sea lion bites treated during the same period.
So while both seals and sea lions can bite defensively, the frequency of aggression and biting incidents is clearly higher among sea lions.
Conclusion
While seals and sea lions share some common traits, sea lions tend to be more aggressive due to fierce competition between males during breeding season. Seals are generally more timid and choose to flee rather than fight when encountering humans or other threats.
So if you had to choose one to get in the water next to, seals would likely be the safer option! But it’s still wise to keep your distance and respect the space of all wild marine mammals.
