How did the elephant get so big? Chris Packham explores the four-billion-year story of how a tiny cell evolved into complex, gentle giants.

How did the ostrich come to lay the biggest egg on Earth? Chris Packham explores the way reproduction has shaped life on Earth and the surprising evolutionary origins of sex, eggs and birds. It's a four billion year journey contained within a shell.

How did the bat get so hungry? Chris Packham explores how the drive to find food has shaped animal life. The origin of bums, guts, jaws and super-hearing.