Time Out in the Antarctic With Crabeater Seals

LIKE BOOKENDS, CRABEATER SEALS NAP ON AN ROCK OUTCROP IN THE PACK ICE ZONE SURROUNDING THE ANTARCTIC. IMAGE: ©MARK SETH LENDER

MARK SETH LENDER. IMAGE THANKS TO: ©MARK SETH LENDER

The South Shetland Islands are home to sea birds, penguins, and a variety of other Antarctic wildlife. Living on Earth's Explorer-in-Residence Mark Seth Lender shares a story of the crab-eater seals relaxing on the Antarctic ice.

This story was first aired on Living on Earth July 2020
Listen as this remarkable storyteller recounts his experience.
And read below

Crabeater Seals Take a Break

Two crabeater seals, one older one younger (related perhaps) drag themselves out, and up, and onto the worn basalt crowning from the sea just beyond the fast ice. And lay down there. The head of the one to the tail of the other fitted, like parts, of something larger. Except there is no room for anything larger. Them, it suits. One yawns, palate as purple as a lilac tree in bloom, teeth shaped like nutmeats but sharp and meant not to be chewed but to do the chewing. Potentially. Because, after that yawn... Inanimate. Not so much as a shrug. Crabeaters, taking a break.

TWO CRABEATERS SHARE AN OUTCROP, PERHAPS TO GET AWAY FROM THE CHAOTIC CHIN STRAP PENGUINS. IMAGE: ©MARK SETH LENDER

They will take one anywhere they can. They have no country. No allegiance of terrain except for an easy in, and an easy out. The chinstrap penguins nearby, they are the regulars. They have more particular wants. Noisy, temperamental, in constant transit from island to sea to island to sea. It is early for them to nest but they are considering it, examining each and every possible location and what will work and what will not. Conflict is the predictable consequence with space at such a premium.

Two get into a flipper fight slapping each other in a way that does no damage but probably stings. No doubt enough to get the point across. While the crabeaters ignore all of it. They simply remain in place. Silent. Neither stretching nor shifting their bulk nor arching their bodies as seals sometimes do to adjust their contact with the ice. Which means the crabeaters are neither cold nor hot. Are neither hungry nor overfull. If life is tough, they aren’t telling. Or if it is easy, and good. Their point is to be there. And they already are. But just as easily their place could be... somewhere... Else.

Chin Strap Penguin

Antarctic Landscape

Gentoo Penguin

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Top 10 Fast Facts on Crabeater Seals

SOUND ASLEEP ON THE ICE. PERHAPS IT IS BECAUSE IT SPENT THE NIGHT DIVING FOR KRILL. IMAGE: ©MARK SETH LENDER

1. These pinnipeds do not eat crabs! While many species have names that suggest their habits, weaver birds are a good example, crabeaters (Lobodon carcinophagus)are not crab eaters. Crabeater seals eat krill. They also eat cephalopods (octopus and squid) and Antarctic fish, but krill and tiny crustaceans make up about 95% of their diet.

2. Unique tooth structure: Crabeaters have developed a tooth structure similar to the baleen on baleen whales. They feed by sucking in krill-filled seawater, then forcing it out between these specialized teeth trapping the krill in their mouth. Lunch!

3. They may look lazy but …. Crabeater seals forage from dusk to dawn (yes, they are night feeders) divng for up to 16 hours at a stretch! They can dive up to 1378ft (430m), although most foraging dives are 65-100ft (20-30m) and can stay submerged for 11 minutes.

4. Bringing up Baby Crabeater Seals: While crabeater seals do sometimes congregate in groups of several hundred, when it comes time to give birth, females go solo, choosing an ice flow to give birth on alone. Soon a male will join her. He may or may not be the biological father, but he will defend the mother and pup, hoping to mate with the female when she is ready again. Pregnancy lasts 11 months!

CRABEATER SEALS GROW FROK 44 POUNDS TO 110 POUNDS IN ONLY THREE WEEKS.

5. Crabeaters Grow Amazingly Fast! Females have a single pup, born at about 44 pounds (20kg), but by the end of the nursing period, about three weeks, the pup can weigh-in at 240 pounds (110kg)! No one has established yet if that 3-week period is natural, or if the male forces the pup away.

6. Crabeater Conservation Status: The crabeater seal population got a lift when whaling eliminated most of their krill eating competition. Now that whales are beginning to recover, it remains to be seen what will happen to the crabeaters. At present, they are the most populous seal species with a status of Least Concern.

7. Crabeater Predators: Leopard seals followed by orca are the primary predators, eating both the pups and the adults.

THE CRABEATER SEAL DOES NOT SEEM TO NOTICE THE SHIPWRECK BEHIND IT. IMAGE: ©MARK SETH LENDER

8. The Biggest Threats is Climate Change: While leopard seals alone are responsible for an estimated 80% of all pups not reaching adulthood, climate change is a far more significant threat. Warming waters has led to a massive decline in its primary food source: krill.

9. Starvation May Come in Good company: Unfortunately, this decline of krill can also cause starvation in many other species including blue and other baleen whales, whale shark, leopard and fur seals, and several penguin species such as Adélie, macaroni, Gentoo, and chin strap.Sea birds are also dependent on krill including the albatross, auklets, and shearwaters, as are fish species like salmon, sardines, and squid.

10. A Last Word on Crabeaters: For now, although the population of crabeaters has declined, it is still healthy. Are you heading to Antarctica? Watch for them in the pack ice zone - they are surly watching you!