Crocodiles are just one of the most fascinating creatures in our planet. In addition to that, they are also quite terrifying. Even more so when scientists have discovered that these cold-blooded reptiles have the ability to sleep even with one eye open.
According to Discovery News, a new study from researchers out of Australia's La Trobe University and Germany's Max Planck Institute for Ornithology shows that crocodiles have the ability to sleep while keeping half of their brain alert — essentially sleeping with one eye open.
The researchers have studied juvenile crocodiles in a special holding aquarium with cameras focused on the reptiles for 24 hours at a time. The reason why juveniles were used is due to adult crocodiles would be too dangerous to work with.
As reported, the researchers tested for use of vigilant, one-eyed sleeping behavior by sending in turn, another crocodile and a human into a holding area.
Most of the time, the crocodiles slept with both eyes closed. However, in both cases, the young test subjects indeed opened one eye and then the other appeared to be sleeping.
Dr. John Lesku, the lead researcher said, "We had a human stand still next to the tank for 10 minutes - the animals responded to that quite strongly and watched the person closely with one eye,"
He added, "After the human left the room they kept looking at the last location of the person with the other eye closed. This suggests that crocodiles have the same kinds of brain activity that birds do."
According to The Guardian, the three test juvenile saltwater crocs were taken from northern Queensland and then placed into the aquarium.
A further experiment involved the researchers putting new young crocodiles in the group and again, the animals opened one eye and kept watch, possibly due to young crocodillians can be vulnerable to predators and group together to minimize any threat.
Dr. Lesku also said that his colleagues at the Max Planck Institute in Germany had discovered that this behavior is also present in adult Nile crocodiles and even Caimans.
"This suggests that this is a crocodilian trait not specific to one species," he said.
In a similar report by BBC, the crocodile is just one of the many species in the animal kingdom who does this. It was noted that birds and even aquatic mammals, such as walruses and dolphins, are also doing what they called a "sleeping with one night open."
So before thinking that you can sneak safely past a sleeping crocodile, you better think again.
