Snakes Gang Up to Hunt Prey—a First

Many of us have seen those classic wildlife documentaries of wolves or lions working in packs to chase down their prey.

But snakes?

A new study has revealed that Cuban boas coordinate bat hunts in the sinkhole caves of Cuba's Desembarco del Granma National Park.

It was already known that the reptiles hang from the ceiling at the cave entrance and catch Jamaican fruit bats that roost inside.

But Vladimir Dinets, a psychologist from the University of Tennessee at Knoxville, found that snakes position their bodies close together, closing off the bats' flight path and resulting in more successful captures. (Also see "Watch Snakes Grab Cave Bats From Mid-air.")

“They just block the entire opening, so there’s nowhere to go,” says Dinets, whose paper, published recently in the journal Animal Behavior and Cognition, is the first scientifically documented observation of coordinated hunting among snakes.

According to his observations, solo snakes caught fewer bats than group hunters.

Reptilian solitude is “a big misconception. They’re quite social,” he says—and it pays off at dinner time. [nice!]

Snakes aren't the only surprisingly cooperative killers.

Alligators and Crocodiles

These reptiles also “use some crazy techniques” to catch prey in tandem, Dinets says.

In a 2014 study, Dinets describes mugger crocodiles in Sri Lanka swimming in increasingly tighter circles around fish, then take turns darting through the dense schools to catch their lunch.

Scientists have also observed American alligators working together to nab prey. Larger animals will drive fish into shallow water, where smaller gators block them from getting away. Then both sizes feast on the trapped victims. (See "Massive Alligator Caught on Video Is Not a Hoax.")

Spiders

More than 12 species of tropical spiders live in colonies and hunt together, Leticia Avilés, an evolutionary biologist at the University of British Columbia, says by email.

For instance, the Ecuadoran species Theridion nigroannulatum hunts by hanging sticky strands of web from a leaf and then hiding. When prey flies into the strands, the waiting arachnids attack, carrying the spoils back to the colony to share. (Read "Jumping Spiders Can Think Ahead, Plan Detours.")

Hornets

Japanese hornet colonies send a scout to mark honeybee hives with a pheromone, which pinpoints the location to the rest of the hornet colony.

The two-inch-long predators then fly in and kill the bees, which they turn into a paste to feed their larvae. (Related: "World’s Biggest Hornet—Inside Deadly Attacks.")

But sometimes, the bees outfox the hornets.

In those cases, the bees will lure the scout into the hive and swarm it, vibrating their wings and increasing the temperature until they roast the spy alive.

Groupers

Nassau grouper seek the kindness of strangers when looking for a meal.

These large fish of the western Atlantic “team up with another predator, like a moray eel,” says Scott Heppell, a marine biologist at Oregon State University.

If a prey fish is hiding in coral, the grouper will stay on one side and the moray on the other, so the fish is “hunted from both sides.” (Also see "Fish and Eels Team Up to Catch Prey, Rare Among Animals.")

Sometimes, groupers will even help out with scuba divers hunting invasive lionfish. When divers appear with spears on Little Cayman Island, the Nassau grouper "act like bird dogs and 'point' to the lionfish, letting us know where it is," says Heppell, who works with the Reef Environmental Education Foundation.

"I think they hope [the divers] spear it for them and then provide them with a spicy snack.”

As evidence of this, the groupers ignore divers without spears and trail along after divers that have them.

Just call them grouper groupies.

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