Certain Alligators and Crocs Use Twigs as Lures to Capture Nesting Egrets
Crocodilians, those seemingly mindless eating machines are actually a lot smarter than most people think, according to a research study published in the journal Ethology Ecology and Evolution. The study took a look at how mugger crocodiles (Crocodylus. palustris) and American alligators (Alligator mississippiensis) use tools, in this case, sticks, to capture birds who are searching for twigs to build a nest. Lead author Vladimir Dinets of the University of Tennessee traveled to the Madras Crocodile Bank in Tamil Nadu, India and observed mugger crocodiles balancing twigs on their snouts. The reptiles would remain still for hours, balancing the twigs in such a way as not to disturb them. Dinets watched as an egret came over and attempted to grab one of the twigs only to be surprised by the crocodile, which lunged at the bird, just missing it. Two other co-authors of the study noticed similar behaviors with American alligators over a 13 year period while working at Florida's St. Augustine Alligator Farm Zoological Park.
Photo Credit: Vladimir Dinets/University of Tennessee
Mugger crocodiles and American alligators use twigs as lures to capture nesting birds.
The scientists then conducted a one year study of the reptiles at four different locations in Louisiana and confirmed their findings that alligators and crocodiles use twigs to lure egrets so they can eat them. The scientists also noticed that these predators covered their snouts with twigs in the spring, which coincides with the nesting season, which makes these ancient animals aware enough to observe bird behavior and know when to use the twigs as lures. This marks the first time a reptile was observed using a tool as a lure to capture prey and the first known case of a predator reptile using a lure that coincides with the seasonal behavior of prey, in this case the building of egret nests.
The full paper can be read on the Ethology Ecology and Evolution website.