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]

11 Masks That Will Keep You Safe and Stylish

Design Safe/Designer Face Covers/Its All Goods
Design Safe/Designer Face Covers/Its All Goods

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Prices subject to change.

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A Two-Toed Sloth Accidentally Hitched a 40-Mile Ride in a Truck's Engine Bay

Tony Hisgett, Wikimedia Commons // CC BY 2.0
Tony Hisgett, Wikimedia Commons // CC BY 2.0

Most sloths move at a maximum speed of 6 to 8 feet per minute, but one two-toed sloth in Costa Rica shattered that pace on a recent joy ride. As Jalopnik reports, the female sloth traveled 40 miles after sneaking into a truck’s engine bay undetected.

The vehicle's drivers noticed something was out of place when they stopped to check the engine and saw a tuft a fur. They reached out to Toucan Rescue Ranch, a wildlife rehabilitation center near San Jose, which identified the stowaway as a two-toed sloth. Though it had been on board for over an hour, the animal managed to survive the road trip unscathed.

The animal caretakers at TRR dubbed the sloth Lola la Trailera, or "Lola the Truck Driver," after the 1983 Mexican action movie of the same name. She was exhausted and aggressive when she arrived at the center, but after feeding her a diet of Pedialyte, wild leaves, and steamed veggies, the caretakers were able to restore her to full health. She was returned to the forest she originated from following six days of rehabilitation.

A sloth's usual lack of speed isn't a sign of laziness—it's a survival tactic. Fat and protein are limited in the rainforest canopies where sloths reside, so they must conserve energy by limiting their activity. But as Lola la Trailera proved, sloths have the potential to move much faster with a little assistance.

[h/t Jalopnik]