Crocodiles and alligators may have tough hides, but it turns out their armored skin is actually super sensitive.

Tons of theories over the years have tried to explain the bumps on croc and gator skin, but a new study from Vanderbilt University reveals these mystery bumps are full of nerves that provide the animals with their sense of touch. In fact, these bumpy beasts have skin that’s more sensitive to pressure and vibration than human fingertips.

So why does it matter that crocs and gators are even touchier than we thought? Not only do these bumps allow the animals to locate and target prey, they also help identify what they’ve snapped up in their jaws.

The most sensitive bumps are actually located inside the mouth and near the teeth. Researchers thinks this helps female crocodiles and alligators delicately break ready-to-hatch eggs and carry the hatchlings in their jaws. If these bumps weren’t sensitive enough, the mothers might accidentally crush their young into a mid-afternoon snack.

Crocs and gators can also detect tiny water ripples created by swimming prey. Even if their hearing is disrupted, the bumps still help the predators locate the source of the movement. Direct contact of the prey with the predator’s skin also provides key sensory information that lets the crocs and gators strike faster and more acurately.

So next time you’re swimming through gator-infested waters, just remember: the big lizards know you’re there.