Cache You Later: Leopard Seals and Their Leftovers

April 29, 2023

Despite what Coca Cola commercials would have you believe, polar bears and penguins have never met. Polar bears are apex predators of the Arctic, while penguins are only found in Antarctica.* That doesn’t mean penguins are safe from predation…

…because leopard seals.

Leopard seals may look cuddly, but don’t be fooled. Females get up to 12 feet long and weigh more than 1100 pounds – quite literally the size of polar bears.** Leopard seals are fierce predators, taking penguins, fur seals, bottom-dwelling ice fish, and pretty much anything else they can get their teeth into. They’re also fiercely competitive, frequently stealing kills from other leopard seals.

Much of what we know about the hunting behaviour of leopard seals comes from studies done by Doug Krause with support from National Geographic. Check out this amazing video featuring footage from “crittercams” mounted on leopard seals:

Krause’s studies also revealed a previously unknown behaviour in leopard seals – caching! Like ermines in the Arctic, leopard seals will kill more prey than they immediately need, storing the excess for later.

While caching seems cruel, it’s an important survival skill for predators whose food supplies vary from year to year, or at different times throughout the year. After all, penguin chicks and fur seal pups are only small and vulnerable for a short time… after which a leopard has to work a lot harder to catch a meal. 

Unlike ermines, who can hide their caches so well not even scientists can find them, leopard caches are often raided by other predators. Here’s a deleted scene from Polar: Wildlife at the Ends of the Earth, that illustrates the challenges:

The leopard seal raided the penguin colony all day, patrolling the floe edge as birds came and went. Breeding season is almost over, and the surplus food it provides will dwindle. The leopard must catch all she can, even if she’s no longer hungry.

The seal swims away from the colony, a carcass in her jaws. Cruising through leads in the pack ice, she looks for a place to store it. Perhaps this crack will do? She wedges the carcass into the gap, but skuas descend instantly, looking for a free meal. The leopard barks and lunges at them, but she’s outnumbered. Pulling the carcass free, she dives to escape the birds, looking for a better larder.

There, under the roots of a grounded iceberg. The seal tucks her prey into the hollow. It starts to float, so she nudges a rock on top to hold it in place. She’s the only leopard seal for miles. The food will be safe here until she returns for it.

She’d better not wait too long – Krause’s studies showed that underwater caches are quickly discovered – and devoured – by ocean scavengers!

Bonus for Teachers and Homeschoolers:

While googling for the video clip this morning, I happened upon a lesson plan National Geographic has assembled for leopard seals. You can find the video and other resources at this link.


*And a few other places South of the Equator.

**Also larger than males of their species, which is unusual in mammals!

Polar: Wildlife At the Ends of the Earth comes out in 3 more sleeps! EEK! Pre-order a copy from your local independent bookstore to reduce your carbon footprint AND support a cornerstone of your community. You can also order from your favourite online retailer.

Don’t forget to check my Public Appearances page for Polar virtual events and live events happening near you! Are you a teacher or librarian? I’m available for author visits in May and June – contact me to secure your spot.  

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