The discovery that temperature and humidity may influence sleep patterns more than light and darkness could help sleep therapists develop new approaches to issues such as insomnia, reports BusinessDay.

Prof Paul Manger of the School of Anatomical Sciences at the University of the Witwatersrand studies animal brains, in part to understand the peculiarities of sleep. He was part of a team that discovered that duckbilled platypuses have 80% of their sleep as rapid eye movement (REM) sleep. Humans have about 20%.

They also found that elephants in the wild catnap about two hours a night and that the smaller the animal, the more they are likely to sleep. The record holder for most sleep in mammals is the little brown bat, at 18 hours a day.