Galapagos Wildlife | < 1 MIN READ

Islands of the High Hopes – Galapagos Sea Lions

User Avatar Written by: Nathalie Moeller
Close up of a sea lion's head.

The sea lions that lounge on seemingly every available sunny spot in the Galapagos Islands, from benches to stairways, can appear quite comical. However, do not be deceived by this lazy display of these Galapagos animals– male Galapagos sea lions are territorial and fight viciously to defend their territory. This aggression is so extreme that those males without land are forced to distance themselves from the territories of other males and form what is known by Galapagos locals as ‘bachelor colonies.’

Sea lion colonies

Galapagos sea lion colony

Sea lions usually live in large colonies and can be found resting on the beach

Galapagos sea lions live in colonies ranging from 5 to 30 females, in addition to their young. These groups are dominated by one alpha male and referred to as harems. However, these groups are not true harems because the females are allowed to come and go as they please, even wandering into other territories. This perhaps contributes to the aggressive nature of the bulls. The bull, growing up to 7 feet long and weighing up to 800 pounds, is an enormous creature and can be a fearsome sight.

Alpha males at their strongest

Males are not so enormous for the sake of being big. Sea lion males work extremely hard to protect their harem and prevent other males from mating with their ladies. In fact, male Galapagos sea lions spend the vast majority of their time swimming from border to border defending their territory, and they will persistently reject any attempt by a passing male to seek fortune by forming a new harem. This effort to protect their land is so extreme that the males do not eat throughout their entire reign.

Interestingly enough, the alpha males of each harem seem to be aware of the males that neighbor their territory and are able to recognize them by sound, sight, and smell. Once they have come across the same bull several times, they display reduced aggression towards this bull. After spending some time in the islands, you are likely to see one of these bulls, thrusting its head out of the water and giving out loud barks to scare away any potential opponents; this is an indication of territorial ownership.  When snorkeling with Galapagos sea lions, you can even hear the males’ barking noises underwater too!

Competition of Galapagos sea lions for territories

However, the level of aggression is also a result of the extreme competition for the territories. There are significantly more males than harems, meaning that there is always a lonely male searching for his turn to reign. Fights frequently break out among males, and they often result in injury or even death with the winner becoming the head of the colony. The fights begin with loud barking and the males stretch out their necks, testing each other’s bravery. At this point, if courage has yet to falter, the males begin to push each other and bite the neck of their opponent. For these fights, males must be equipped with a muscular, thick neck to avoid harm to their vital organs. In fact, it is not uncommon to see battle scars on male Galapagos sea lions from injuries during previous fights. A large amount of blubber around their necks provides extra cushioning from other males’ strong bites.


Males do not hold territory for more than a couple of months before they are defeated. Because the males do not feed while protecting their territory, they eventually become extremely feeble and malnourished. By the time a male is defeated by another male, he has simply become too weak and is overpowered by the better-nourished male.

The castoff males

However, this whole process results in a large number of unwanted and weak bachelor males. As expected, these bachelor males are not tolerated around the harems and are forcefully fought away from all territories. Thus, the shunned males congregate together in less favorable areas, forming their own peaceful colonies, which are tenderly known as ‘bachelor colonies’. Sea lions are gregarious Galapagos mammals and even when males enter a bachelor colony, they need to remain social.  Behaviorally, though, they know their future mating time will come, and so each location that shows a bachelor hangout is truly an “Island of High Hopes”. Several of these colonies exist on the islands, allowing the defeated males to relax and gather their strength until they are once again able to defeat an alpha male. The younger and smaller males likewise live in these colonies until they are stronger and able to fend for their own territory. The rejected ones may stay in these colonies for anywhere from six months to a year.

Galapagos animals: sea lions

Galapagos sea lions are known for being territorial creatures

Where to find a bachelor sea lion colony

The most visited of these colonies is on the cliffs of South Plaza Island, but in many other dense colonies is easy to observe where the bachelors are. Here, explorers are able to walk among the bachelors as they lounge on rocks and play in the water, at peace without the threat of alphas or the lure of females. Some of these Galapagos sea lions may be notably injured, but this is perfectly normal. Their social behavior shows occasional aggression in order to have a chance to catch a mate and pass their genes to the next generation. This type of natural selection has been studied by scientists and is labeled as sexual selection. While we humans describe it as aggression, sea lion society may just call it another day in paradise.

Blog Reviewed & Edited by: Francisco Dousdebés
All Images: Francisco Dousdebés