Lion prides living along the Skeleton Coast of Namibia – a hyper-arid coastline once called "The Gates of Hell" by Portuguese sailors – have developed an unusual taste for "seafood".

A new study details how two desert lion prides in the Skeleton Coast National Park have adapted to hunt and feast on a marine-based diet, almost exclusively made up of Cape fur seals, greater flamingos, and cormorant seabirds. As reported in The Namibian Journal of Environment, a marine diet made up around 86 percent of the biomass eaten by the two prides over 18 months between 2017-2018. All in all, that includes at least two greater flamingos, 60 cormorants, and 18 seals.

Beach-going lions have also been seen rooting around the intertidal zones of Namibia’s coast, hinting that they may have also learned to snack on shellfish, crabs, and sea turtles, although this is yet to be officially documented.

This corner of northwest Namibia is not an easy place for big cats to live. On top of its extremely arid climate, large swaths of the wilderness were caught up in the Namibian struggle for independence that lasted from 1966 to 1989. Furthermore, the 1980s witnessed intense competition between farmers and lions, resulting in a near total collapse of the desert lion population in the Skeleton Coast for over a decade. Just like the rest of the world's increasingly fragmented lion populations, they also have to fight against human activity, climate change, and loss of habitat.

A Lionesses foraging along the Namibian coastline and catching cormorants on a small island. Courtesy of The Namibian Journal of Environment

But by 2002, lion populations started to rise from the ashes and recover. They were first spotted eating seals in 2006, which researchers initially assumed was an opportunistic last resort for the lions, whose usual dinners of ostriches and oryx were off the menu. However, it seems that this marine diet has proved to be a rich and long-standing source of energy for the population.

Philip Stander, the researcher, notes that polar bears are the only other large land-dwelling carnivores that have been documented eating seals outside of Namibia. Perhaps, they suggest, this unusual desert lion diet arose because of the unique conditions along the Namib coastline where seals breed on a continent, not an island, that’s also inhabited by carnivores and minimal humans. However, adopting a marine-based diet when times get tough is not completely unheard of in the wider animal kingdom. For example, coyotes in the arid corners of Baja California have been recorded eating marine mammals, seabirds, and turtles.

If you thought that was strange, you should check out the incredible images and video footage of hares eating lynx and other meat in Canada's Yukon region.

Edited 30/01/2019: Updated in light of comments from Dr. Niki Rust