"These discoveries are interesting not just because they show how easy it is to underestimate the intelligence of even relatively familiar animals, but also because crocodilians are a sister taxon of dinosaurs and flying reptiles," the study adds. This suggests that even dinosaurs were "likely very complex as well."
This, and related research, indicates that scientists are finally catching up with a story-teller who regaled audiences in ancient Greece during the fifth century, BC.
In one of Aesop's fables, "The Crow and the Pitcher," a crow used stones to raise the level of water in a pitcher so it could quench its thirst. That story fascinated scientists at the University of Cambridge (where else?) so much that they decided to find out if Aesop was on to something.
They demonstrated that a rook, a member of the corvid family of bright birds that includes crows, would do just as Aesop had suggested if that was the only way he could snatch a worm floating on the top of the water in a pitcher.
The crow not only used stones to raise the water level so it could reach the worm, it also figured out that it could do it a lot quicker if it used a few larger rocks instead of a lot of smaller ones. And it didn't check to see if it could get the worm after it dropped each stone. When the water was high enough, it grabbed the snack.
That won't surprise many bird lovers, because corvids, like chimps and apes and various other animals, have been documented using tools to extract lunch from places they could not otherwise reach. Crocodilians are the latest now to join that exclusive club, but maybe not the most surprising.
At least one crow in Russia has taken it one step farther. As seen in a video posted to YouTube last winter, the crow used a plastic disc as a sled to repeatedly slide down a snow-covered roof. She used a tool not for food, but for fun.
Scientists at the University of California, Santa Cruz, have even found a fish that uses a tool to prepare its meal. While studying the orange-dotted turkfish near the island of Palau in the western Pacific, evolutionary biologist Giacomo Bernardi made a startling discovery.
Repeatedly, he watched the turkfish dig a clam out of the mud and then throw it against a rock over and over again, until the clam shattered, yielding up the fish's lunch.
Bernardi, by the way, thinks there may be many species of fish that use tools. It's just pretty hard to see them in the depths of the ocean.