In a cloud, pure water can stay liquid down to nearly -40°C: to freeze, it needs a 'seed'. Some bacteria, such as Pseudomonas syringae, carry surface proteins that make water freeze at around -2°C. Swept into the atmosphere, they help ice crystals form, and with them rain and snow. Such biological ice-makers have been found in snowfall on several continents.
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.