Enlarge / Even hermit crabs have particular person patterns of conduct — personalities, if you happen to like. When scientists ignore the consequences of such variations, they might produce analysis that’s flawed. (credit score: NurPhoto by way of Getty Photographs)

A number of years in the past, Christian Rutz began to wonder if he was giving his crows sufficient credit score. Rutz, a biologist on the College of St. Andrews in Scotland, and his staff have been capturing wild New Caledonian crows and difficult them with puzzles made out of pure supplies earlier than releasing them once more. In a single take a look at, birds confronted a log drilled with holes that contained hidden meals, and will get the meals out by bending a plant stem right into a hook. If a fowl didn’t strive inside 90 minutes, the researchers eliminated it from the dataset.

However, Rutz says, he quickly started to understand he was not, in actual fact, finding out the abilities of New Caledonian crows. He was finding out the abilities of solely a subset of New Caledonian crows that shortly approached a bizarre log they’d by no means seen earlier than—perhaps as a result of they have been particularly courageous, or reckless.

The staff modified its protocol. They started giving the extra hesitant birds an additional day or two to get used to their environment, then making an attempt the puzzle once more. “It seems that many of those retested birds abruptly begin partaking,” Rutz says. “They only wanted a bit of bit of additional time.”