Picky Penguins Aren’t Surviving the Antarctic Warm-Up

Forget about a polar bear stranded on the ice float, the new mascot for global warming could be a penguin turning up its beak at a diverse diet.
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The gentoo penguin’s (left) adventurous eating habits are likely why it’s adapting better to a warmer environment than the picky chinstrap penguin (right). (Photo: Rachael Herman/LSU)

The gentoo penguin’s (left) adventurous eating habits are likely why it’s adapting better to a warmer environment than the picky chinstrap penguin (right). (Photo: Rachael Herman/LSU)

If you were the type of kid to pout over a plate of broccoli, you might remember your parents saying something like, “If you’re not going to eat this, you’ll starve.” While that was (hopefully) an empty threat, scientists are finding that it mirrors the unfortunate reality for at least one species coping with climate change: chinstrap penguins.

Chinstrap penguins live on the Antarctic Peninsula alongside the closely related gentoo penguins. In the last 50 years, average air temperatures in the region have increased by about five degrees Fahrenheit. That makes it the most rapidly warming region in the Southern Hemisphere, according to the British Antarctic Survey.

(In case you were wondering, chinstrap penguins do have the face markings from which they get their names. Gentoo penguins, on the other hand, have orange beaks. Both have the black backs and white stomachs that give them that signature tuxedo look.)

When closely related species live in the same ecosystem, they tend to specialize the type of food and resources that they use, so that there is less competition between species. But that happy co-existence comes with a tradeoff.

Despite similar habitats and diets, scientists have observed “dramatic declines” in the chinstrap penguin population in recent years. The gentoo penguin population, meanwhile, has expanded. A newly published study in Marine Ecology Progress Series, by lead author Michael Polito of Louisiana State University, explains the divergence.

When closely related species live in the same ecosystem, they tend to specialize the type of food and resources that they use, so that there is less competition between species. But that happy co-existence comes with a tradeoff, Polito and colleagues write: “Species with specialized habitat or dietary requirements are likely to be highly sensitive to environmental changes.”

From 2007 to 2011, Polito and his colleagues analyzed stomach and feather samples of a colony of penguins living on the Antarctic Peninsula, as well as the availability of their main prey, a shrimp-like crustacean that’s called krill. Krill rely on sea ice for protection and food, so when temperatures rise and ice melts, there are fewer krill in the ocean.

Researchers found that chinstraps were pickier penguins—they ate mostly krill—whereas gentoos were more adventurous, adding various types of fish to the menu. Krill comprised nearly 100 percent of chinstrap diets (measured by wet mass of stomach contents), whereas they only accounted for 79 percent of gentoo diets.

Oddly enough, chinstraps actually forage further offshore than gentoos, in order to reach the krill swarms. “This and other studies indicate that their foraging choices may be a reflection of small-scale changes in prey availability,” Polito and colleagues write.

Call it a cautionary tale. As climate change rears its ugly head in many ways, some of our preferred food sources may disappear. We might all be eating organic crickets in 50 years, so start training your kids to appreciate exotic flavors now.

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