While containing many distinguishable physical characteristics, both crocodiles and alligators possess a similar, yet rare, hunting predatory behavior that allows them to fool nest-building birds. In a 2013 study, researchers found that the Crocodylus palustris and the Alligator mississipiensis use tools to capture their prey.
Crocodiles and alligators lure birds by stacking and balancing twigs on their head. After, they would place themselves in shallow waters and imitate a log, patiently waiting for their prey and lunging immediately when a bird wades closely.
How Do Crocodiles and Alligators Differ From Each Other?
Known as massive reptiles that trigger fear for almost everyone, crocodiles and alligators are stealthy, carnivorous predators that live a semiaquatic lifestyle. Currently, 23 known species of crocodiles fall under the Crocodilia order, which includes three distinguishable families: the Alligatoridae, the Crocodylidae, and the Gavialidae. Meanwhile, alligators only have two living alligator species. (Source: Basic Biology)
As alligators are confused with crocodiles most of the time, one can differentiate the two with their physical differences. While crocodiles have a longer and V-shape resembling snout, alligators have a shorter, U-shaped snout.
In addition to that, the upper jaw of a crocodile is similar in size to its lower jaw, with their lower teeth showing outside their upper jaw when they close their mouth, with a noticeably huge fourth tooth. Contrarily, alligators have a wider upper jaw, with their lower teeth mostly hidden with a closed mouth.
A physiological difference between the two species of the Crocodilia order resides in their salt glands and sensory pits. The salt glands of crocodiles are on their tongues and excrete the excess amounts of salt, with their sensory pits located throughout their entire body. Contrariwise, alligators have non-functional salt glands, with their sensory pits found only near their jaws. (Source: Animal Corner)
Similarities in Hunting
While most predators have built-in anatomical lures to trick their prey, other predators resort to using environmental tools to capture their victims. Chimps utilize sticks to harvest ants, and dolphins use marine sponges to uncover hiding prey in the ocean’s sand. With that said, even crocodiles and alligators have a few tricks up in their sleeve. (Source: Live Science)
According to a 2013 research article published in Ethology, Ecology, and Evolution entitled Crocodilians use tools for hunting, researchers observed the rare sight of crocodiles and alligators using sticks as hunting lures. The Crocodylus palustris and the Alligator mississipiensis exhibited this behavior. The authors stated that this was the first known case of a predator using objects as lures while accounting for the seasonality of the prey behavior. (Source: Ethology, Ecology, & Evolution)
The experts observed how the reptilian predators would place themselves near the shore in shallow waters as they pretended to be a log. If any nest-building birds waded too close, fooled by the sticks and the crocodile’s log-imitation, the crocodiles would immediately attack.
The researchers found that the occurrence of sticks on crocodilians was not random. It was more often seen in those reptiles living near the bird nests and was only witnessed during the nesting season. Of course, it could be that floating sticks randomly find themselves atop a croc’s nose, but the researchers say that floating sticks are extremely rare in the waters observed. This means that it’s more likely that the reptiles are deliberately collecting and using the twigs as bait. If this is the case, it would be described as tool use.Rachel Nuwer, The Smithsonian
(Source: Smithsonian Magazine)