When tickled on the back and belly, rats emit ultrasonic chirps around 50 kHz, inaudible to you, which researchers regard as a form of laughter. They make little jumps of joy and chase the tickling hand. The response is strongest in young rats and vanishes when they are anxious, just like human laughter.
In 2022, a young tagged bar-tailed godwit flew from Alaska to Tasmania in about 11 days of nonstop flight, covering 13,560 km without eating, drinking or landing. Before departure, these birds pile on huge fat reserves and shrink their digestive organs, which are useless during the journey.
To escape rivals, a dung beetle rolls its ball of dung in a straight line. At night, it holds its course using the glowing band of the Milky Way. In a planetarium, researchers showed that beetles rolled straight under a starry sky but wandered aimlessly when the galaxy was switched off. It was the first animal known to navigate this way.