Spiders lack extensor muscles at some of their leg joints. To stretch their legs out, they raise the pressure of their hemolymph, their 'blood', much like a hydraulic jack. That is why dead spiders curl up: the pressure drops and the flexor muscles win. Engineers have even turned dead spiders into tiny robotic grippers.
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.