Nudibranchs, the Butterflies of the Sea, May Also Be Ruthless 'Kleptopredators'

Wilfred Hdez, Flickr // CC BY 2.0
Wilfred Hdez, Flickr // CC BY 2.0

There's nothing ruder than taking someone's food without asking—except maybe waiting until they're finished eating and consuming them whole so you can get those extra calories. As Gizmodo reports, this way of feeding, dubbed "kleptopredation," may be how at least one group of mollusks prefers to take its meals.

In their recent study published in the journal Biology Letters, European scientists explored the eating habits of nudibranchs. Nudibranchs are soft-bodied sea slugs that are sometimes called "butterflies of the sea" for their colorful appearances. The striking sea creatures are also effective carnivores, preying on sponges, anemones, and occasionally other nudibranchs.

For their experiment, the researchers placed members of a nudibranch species known as the pilgrim hervia (Cratena peregrina) in a tank with one of their favorite treats: hydroids, a relative of jellyfish. Plankton were also present for the hydroids to eat. When given a choice between the empty-stomached hydroids and hydroids that had just consumed or were in the middle of consuming plankton, the nudibranchs chose the well-nourished prey in 14 out of the 25 trials. According to the study authors, plankton can make up at least half of the nudibranch diet this way even though it's being preyed upon indirectly. This means that a nudibranch's interactions with a plankton-loving cnidarian could go beyond the basic predator-prey relationship.

Though the nudibranchs' preference for hydroids that had eaten plankton wasn't random, that doesn't automatically mean it's a case of kleptopredation. It's possible that the sea slugs simply chose the prey that looked larger, or they went after the hydroids that had just fed because the stinging cells the cnidarians use to hunt were worn out and therefore less harmful.

If more research does support the theory that the animals target full prey before giving them a chance to digest, that would add the unique predation method to the already impressive roster of nudibranch abilities.

[h/t Gizmodo]

Why Are There No Snakes in Ireland?

iStock
iStock

Legend tells of St. Patrick using the power of his faith to drive all of Ireland’s snakes into the sea. It’s an impressive image, but there’s no way it could have happened.

There never were any snakes in Ireland, partly for the same reason that there are no snakes in Hawaii, Iceland, New Zealand, Greenland, or Antarctica: the Emerald Isle is, well, an island.

Eightofnine via Wikimedia Commons // Public Domain

Once upon a time, Ireland was connected to a larger landmass. But that time was an ice age that kept the land far too chilly for cold-blooded reptiles. As the ice age ended around 10,000 years ago, glaciers melted, pouring even more cold water into the now-impassable expanse between Ireland and its neighbors.

Other animals, like wild boars, lynx, and brown bears, managed to make it across—as did a single reptile: the common lizard. Snakes, however, missed their chance.

The country’s serpent-free reputation has, somewhat perversely, turned snake ownership into a status symbol. There have been numerous reports of large pet snakes escaping or being released. As of yet, no species has managed to take hold in the wild—a small miracle in itself.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

Intense Staring Contest Between a Squirrel and a Bald Eagle Caught on Camera

iStock.com/StefanoVenturi
iStock.com/StefanoVenturi

Wildlife photographers have an eye for the majestic beauty of life on planet Earth, but they also know that nature has a silly side. This picture, captured by Maine photographer Roger Stevens Jr., shows a bald eagle and a gray squirrel locked in an epic staring match.

As WMTW Portland reports, the image has been shared more than 8000 times since Stevens posted it on his Facebook page. According to the post, the photo was taken behind a Rite Aid store in Lincoln, Maine. "I couldn't have made this up!!" Stevens wrote.

Bald eagles eat small rodents like squirrels, which is likely why the creatures were so interested in one another. But the staring contest didn't end with the bird getting his meal; after the photo was snapped, the squirrel escaped down a hole in the tree to safety.

What was a life-or-death moment for the animals made for an entertaining picture. The photograph has over 400 comments, with Facebook users praising the photographer's timing and the squirrel's apparent bravery.

Funny nature photos are common enough that there's an entire contest devoted to them. Here are some of past winners of the Comedy Wildlife Photography Awards.

[h/t WMTW]

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