Crows pay attention to how the human world works, and often use it to their advantage: Some have been observed cracking walnuts by dropping them from the exact height needed to bust them open on the pavement. But in other cases, they take gravity out of the equation and just drop the nuts in front of cars, letting us do the work for them. These same crows also memorize the pattern of traffic lights to optimize the exact moment they drop the nuts, but also to make sure they only retrieve them when the light is red and the crosswalk sign is on, so they don’t get run over. If you’ve ever been out driving, you know the latter is a skill that only about 10 percent of the human population has mastered.
