Crocodiles use twigs and sticks to lure birds

Dec. 5 (UPI) -- Crocodiles have been found to use twigs and sticks to lure birds by balancing them on their snouts -- the first observed tool use among reptiles.

Vladimir Dinets, a research assistant professor at the University of Tennessee at Knoxville, found that two crocodilian species, namely the mugger and American alligator, used twigs and sticks to catch birds during nest-building season.

Not only is it the first instance of tool use by any reptile, it also is the first time a predator has used a specific period, like the nest-building time for birds, to target prey. The research is published in Ethology, Ecology, and Evolution.

Dinets first observed this behavior in India in 2007, when he saw crocodiles remain still for hours with twigs on their snout, before lunging for their prey.

"They are typically seen as lethargic, stupid, and boring but now they are known to exhibit flexible multimodal signaling, advanced parental care, and highly coordinated group hunting tactics,” Dinets said.

Dinets and his colleagues observed crocodiles at bird breeding grounds in Louisiana. They observed a significant increase in crocodiles placing sticks on their snouts during March to May, the time when birds built their nests.

The reptiles had sticks on their snouts during and after the nest-building season at bird breeding grounds and used sticks only during the nest building season in non-breeding sites.

“These discoveries are interesting not just because they show how easy it is to underestimate the intelligence of even relatively familiar animals, but also because crocodilians are a sister taxon of dinosaurs and flying reptiles,” Dinets said.

[University of Tennessee] [Ethology, Ecology, and Evolution]