THIS is what a croc’s eyes are designed for…
And you’ve been warned.
Years ago, when I visited the Daintree Rainforest in northeastern Australia, I couldn’t help but notice the signs — several of them — warning of crocodiles. Australia is home to two species of the ferocious reptiles, freshwater and saltwater — the latter of which can be found in the Daintree River. And the signs are no joke. Croc attacks aren’t common, but a few do happen every year, and some result in deaths.
Crocodiles aren’t terrifying just because they have huge teeth and a deadly bite, though. It’s that an attack appears to come from nowhere. The animals lurk just beneath the water, with only their eyes keeping a lookout for something tasty — like one of us. Now, new research shows that, while a croc may not see as well as you or I, its eyesight is quite good and well adapted for lying in wait at the water’s surface.
Nicolas Nagloo and colleagues from the University of Western Australia in Crawley took a detailed look at eyes from three young saltwater and two young freshwater crocodiles. “Both Australian species possess a bright yellow iris, a slit pupil and a relatively large lens,” the team notes May 4 in the Journal of Experimental Biology. Such features, which were known before this study, are helpful for seeing in dim light. (The animals, though, don’t have great vision underwater.) Crocs are also equipped with a “mobile slit retina” that helps the animals control how much light reaches the eye during daylight.Dissections and examinations of the cells of the eyes revealed that both species have three types of single cones, a type of double cone and one type of rod. This means that the animals can see colors well.