Scientists now know the answer to why eyelashes are as long as they are. Researchers did tests on the eyelashes of 22 mammals. One used a special wind tunnel and a model eye. The tests produced mathematical models of how wind blows over eyelashes. The conclusion was that eyelashes help protect the eyes from drying out. Also, the best eyelash length is one-third of the eye's width. This was true for many mammals.

Researcher Dr Hu started his research after wondering why his baby kept on moving her eyelids. He said eyelashes in mammals have always been a mystery. There are many opinions, from catching dust to making people blink. It was the first study of eyelashes and wind. It showed that eyelashes cut evaporation of the eye by 70 per cent. They also reduce dust. Hu is good at, "looking at what everybody has looked at, and seeing what nobody has seen."