We like to think that being able to use tools is a skill reserved for just a few highly intelligent animals, but the closer we look at the animal kingdom, the more and more species we discover are capable of using objects to aid themselves in getting food. No longer are humans defined by our ability to use tools, and now, it seems, even rats are getting in on the action.
The brown rats in question were trained to complete a task that has also been used on primates and crows. The task required the rats to use a hooked tool in order to receive a piece of food, in this case a bit of delicious chocolate cereal. The rodents were then placed in another situation, in which they were presented with two choices: They could either use the hooked tool as before to get the cereal, or use an ineffective tool that would get them nothing. The researchers, from Doshisha University, Japan, found that in 95 percent of experiments, the rats selected the correct hooked tool.
We frequently think that rats are not very intelligent, but as the researchers write in the journal Animal Cognition, the rodents are “able to choose appropriate hook-shaped tools to obtain food based on the spatial arrangements of the tool and food, similar to tests conducted in non-human primates and birds.” The rats were less successful, however, when they had to choose between two tools that looked the same, but only one of which would get them food.
It’s increasingly becoming apparent that the ability to use tools is far more widespread than ever imagined. The skill is no longer limited to a few intelligent mammals – such as dolphins, chimpanzees, and, of course, humans – but also occurs in other branches of the evolutionary tree. New Caledonian crows, for example, are prolific tool users and are able to craft objects to retrieve food even when they have never experienced the specific task before.
But it’s not just our feathered friends who turn out to be much brainer than expected. Alligators have been observed balancing twigs on their snouts to lure nest-building egrets close before snapping them up, making them the only known reptile to have been found to use tools. Even some fish, which have the reputation of being particularly dim, have been found to use rocks as an anvil to smash cockles as well as sea urchins in order to get at the nugget of meat inside.
[H/T: New Scientist]
