While humans ignore their biological clocks, little penguins (pictured below) live by them.
Alex Ramsay/Alamy
The inner clock
Lynn Peoples (September 24th: Bloomsbury Tonic (UK), Riverhead Books (US))
Little penguin (Eudyptula minorToucans, tiny bluebirds that live on the coast of southern Australia, make the fast journey from the ocean to their burrows at the same time every day – just after sunset. Timing is key: too early and they miss their last prey of the day, too late and darkness will close in and they will become prey for orcas or feral cats.
Luckily, come-ers can rely on environmental clues like sunlight and moon phases to guide them.
