Reindeer and arctic seals have complex nasal passages to keep them warm; Reindeer can eat and sleep at the same time; This penguin species sleeps by taking about 14,000 micronaps each day; \u2018Naked\u2019 stars are stripped by their partners before they explode; Miracle babies in bags: How close are we to an artificial womb?; Why don\u2019t any deer's legs freeze?