Crabeater Seals in Antarctica | Facts, Identification and Travel tips

Crabeater seals are just one of the many species that make Antarctica such an unforgettable destination. No matter how much you read or hear about the beauty of the southernmost continent, nothing can truly prepare you for the grandeur and beauty of the Antarctic and its wildlife; a visit will create memories that will last a lifetime. 

Among the rich wildlife in Antarctica, beyond the endearing penguins and graceful albatrosses, are six seal species in Antarctica; one of which is the crabeater seal. Not only are crabeater seals the most abundant species of pinniped in Antarctica, but they are the most abundant seal species in the world.

Biology and Behavior of the Crabeater Seal

Where to find crabeater seals in Antarctica?

Crabeater seals have a circumpolar distribution, they can be found across the Southern Ocean. They have an infinity to the ice, migrating with the pack ice annually as it advances and retreats. Despite their southern distribution, some vagrants have turned up on the coasts of New Zealand, South Africa, and even Brazil. Find a detailed map of their range here.

How to identify a crabeater seal?

Crabeater seals are true seals, they lack external ears and have small front flippers. Both sexes are similar in size, weighing between 225 kg and 300 kg; reaching lengths of up to 2.6 meters.

There is considerable variation in the colouration of crabeater seals, but one common feature among many individuals is heavy scarring. Until recently these scars have been previously attributed to leopard seal predation. However, recent studies suggest that much of the scarring may be the result of interactions between other crabeater seals, particularly during disputes over territories and mating. 

It can be challenging at times to distinguish crabeater and Weddell seals. Crabeater seals are often recognised by their dog-like appearance with slightly longer snouts, while Weddell seals tend to have more cat-like features, including an upturned mouth that gives them a distinctive permanent smile. 

Do crabeater seals eat crabs?

The name “crabeater” is a misnomer, although there are crabs in Antarctica, the crabeater seals do not eat them. It is believed that their name was given by the whalers and sealers of the past centuries, who, somehow, were under the misconception that these seals consumed crabs.

Other sources suggest that the name originates from the German term “krebs”, which translates to crabs and other crustaceans such as krill. No matter where the name originated or the reason behind it, the name has stuck.

Crabeater seal diet

Crabeater seals are carnivores, highly specialised for feeding on krill which makes up 95% of their diet. Though krill is the primary food source they also consume fish and squid. These seals possess some of the most specialised dentition in the animal kingdom with interlocking tricuspid teeth uniquely adapted for filter feeding. This remarkable dental structure enables them to engulf krill laden mouthfuls of water and efficiently strain out their prey. Their interlocking teeth act much like the baleen plates of baleen whales, serving as a natural sieve separating their prey from the water. 

Lifespan of a crabeater seal

Their maximum lifespan can be 40 years, though the average lifespan is between 20-25 years.

Breeding and Life Cycle

Mating and delayed implantation

Breeding season takes place between September and December; with the peak of pupping in mid to late October. Courtship displays and mating are both thought to take place in the water.

The gestation period is eleven months, which is due to a phenomenon called delayed implantation. The embryo remains in a dormant state for approximately three months before being implanted in the female’s uterus. This delay ensures the pup is born at a time when the environmental conditions are optimal.

Do crabeater seals have any natural predators?

Leopard seals and orcas

Crabeater seals are vulnerable to two main natural predators; leopard seals and orca. Leopard seals are the most significant threat; particularly to inexperienced pups less than a year old. Among the orca populations that inhabit the frigid Antarctic waters, Type B orcas are known to include seals in their diet. They have developed highly specialised hunting strategies, working together swimming in a synchronised manner to create waves, washing the seals off of the ice floes, a technique known as ‘wave washing’.

Climate change and krill decline

Another emerging threat for these seals is the combination of global warming and ocean pollution. The warming temperatures of the ocean water are resulting in a decline in krill populations, threatening the survival of the seals in the coming decades.

Population and Conservation Status of crabeater seals today

The international Union for Conservation of Nature (IUCN) classifies Crabeater seals as “least Concern” due to their large population size and their widespread distribution; with a current population estimate of at least 7 million crabeater seals. The actual number is thought to be in excess of 10 million with some figures indicating 75 million making them one of the most numerous large mammals on earth. 

The exact population size of crabeater seals remains unknown. The harsh and remote conditions make it extremely challenging to study their circumpolar distribution and obtain accurate population estimates. 

Interesting facts about crabeater seals

• Crabeater seals travel long distances and likely hold the record for the greatest distance travelled inland by any seal; with carcasses discovered up to 113km from open water. 

• Ninety-six mummified crabeater seals were found on Seymour Island, in the Graham Land area of the Antarctic Peninsula.

• The scientific name of the crabeater seal, Lobodon Carcinophaga is derived from Greek and reflects their specialised dentition. Lobodon means ‘lobe-toothed’ and carcinophaga translates to ‘crab eater’. 

• Crabeater seals' primary food source is krill, they can consume 11,000 krill in one single day.

• Crabeater seals are well adapted to their semi-aquatic lifestyle and can hold their breath for up to 20 minutes, diving to depths of over 400 meters.

Planning your trip to Antarctica

The season for cruise trips to Antarctica is short and every journey needs careful planning. To help plan your travel to Antarctica, check out our comprehensive Antarctica travel guide. Since the weather on the continent is ever-changing, an Antarctic cruise is also about accepting uncertainties, and embracing flexibility. You may find itinerary changes to adjust to the whims of the Antarctic weather.

While focusing on the large canvas of Antarctica’s wildlife, do not forget about the smaller aspects that can surprise you just as much as the dramatic landscapes. From curious krill to seals hauled out on ice, these quieter encounters are often the most memorable.

For photographers, even the smallest wildlife moments - such as  photographing a crabeater seal hauled out on the ice can be just as powerful as  towering icebergs or huge penguin colonies. Photography guides in Antarctic cruises will also tell you about the importance of providing a sense of scale for this vast landscape through your images.

Visit Antarctica with Secret Atlas

Visiting Antarctica with Secret Atlas is all about embracing the spirit of adventure. Our Small Ship Expeditions to Antarctica focus on wildlife watching and provide a unique opportunity for photographers and wildlife enthusiasts.

With the rise of ecotourism in Antarctica, we understand the importance of acting responsibly. Our team has a deep understanding of the delicate ecosystem of the white continent and we take every step to minimise the impact of our expeditions on this fragile environment.

To learn more about our immersive Antarctica journeys, get in touch.