If the idea of a cold, motionless sexual partner isn’t one of your turn-ons, then you’re clearly not an echidna. The males of these spiny Australian animals will happily mate with females even if they’re hibernating.

They found echidnas having sex on 26 occasions over the last two years. In 11 of these sessions, the female was accompanied by more than one male and one three occasions, she was with no less than four!  Over a third of the females were torpid – slow to react to things going on around them, and with body temperatures of 10 to 29 degrees Celsius. The males, on the other hand, were always active and had the normal echidna body temperature of 32C.  When