Galápagos sea lion guide: how they hunt, and why they're endangered
The Galápagos sea lion is the most inquisitive mammal of the Galápagos Islands. Learn more about this endangered species in our guide by experts from the Galapagos Conservation Trust.
Galápagos sea lions are, as their name suggests, sea lions native to Ecuador's Galápagos Islands, an archipelago of volcanic islands that straddle the equator in the Pacific Ocean.
They delight every visitor to the Galápagos Islands with their playful antics, especially underwater. Yet many people are unaware about the intricate lives that these charismatic, endangered creatures lead. Our expert guide explains what they are, where they live, how they hunt, and whether they are endangered.
How big are Galápagos sea lions?
Galápagos sea lions are the smallest of the sea lion species – adult females weigh around 80kg compared to California sea lions, the next smallest species, whose females weigh around 95kg.
Are Galápagos sea lions found outside of the Galápagos?
As their name suggests, Galápagos sea lions primarily breed in the Galápagos Islands, though breeding colonies can also be found on Isla de la Plata just off mainland Ecuador.
Are Galápagos sea lions endangered?
Galápagos sea lions are the most commonly seen marine mammal in Galápagos due to their playfulness and curiosity. While usually seen on beaches or swimming close to shore, they can also be found on benches in the middle of town!
However, despite seeming common, they are actually Endangered (last assessed for the IUCN Red List in 2014). The Galápagos sea lion population declined by 60-65% from 1978 to 2001, and since then there has been no evidence of either decline or increase.
The reasons for this massive reduction are only partly understood – it is thought that el Nino events effect their prey abundance and subsequently reproduction and survival. Deaths by disease have also increased in recent years.
How do Galápagos sea lions hunt?
Their smooth and streamlined bodies make sea lions efficient hunters of fish (especially sardines) and other prey. Research has revealed that Galápagos sea lions can make the longest, deepest dives of all the sea lion species – they can dive for over 10 minutes and reach depths of almost 600m!
It is thought that their extreme diving ability, along with other traits, have enabled the sea lions to survive better in an environment where productivity is low and unpredictable.
Galápagos resident and wildlife photographer Tui De Roy observed Galápagos sea lions hunting by corralling their prey ontpo the beach: "Using a pincer movement to prevent their prey’s escape," she told BBC Wildlife, "and increasing their speed to the max, the hunters drove the entire school directly onto the beach, their tightly packed rank generating a mini- tsunami-like wave that washed some fish high and dry." She published her findings as a scientific paper in Ecology & Evolution.
How can you tell the difference between male and female Galápagos sea lions?
The sexes are easy to distinguish – males have a prominent bump on their forehead and can weigh up to four times more than females.
How do Galápagos sea lions reproduce?
Males hold territories on beaches where females are found, rather than direct harems. The more dominant the male, the more land he has and therefore the more females he has access to.
Bulls that fail to secure land tend to form bachelor colonies away from the areas that females frequent.
How many pups do Galápagos sea lions have?
Females give birth to a single pup, which has a unique call to help its mother know where it is. It will feed on its mother’s milk until it is five weeks old and then will start to forage with its mother close to the shore. Pups are dependent on their mothers until they are 11 or 12 months old.
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Are Galápagos sea lions vulnerable to extreme weather?
The main threat to Galápagos sea lions is El Niño, which causes extreme weather patterns. In El Niño years, the marine life on which sea lions depend can collapse, in turn affecting the survival and breeding success of the sea lions.
What are Galápagos sea lions called in Spanish?
While in English they are Galápagos sea lions, in Spanish they are called ‘lobos marinos’ or sea wolves.
The Galapagos Conservation Trust is the only UK charity to focus exclusively on the conservation and sustainability of the Galápagos Islands.
Main image: A Galapagos sea lion on a rock. © Becky Douglas/Galapagos Conservation Trust