Scientists now know the answer to the age-old question of why eyelashes are as long as they are. Researchers conducted many different tests on the eyelashes of 22 mammals. One test used a special wind tunnel and a model eye. The tests were used to get mathematical models of how wind blows over eyelashes. The conclusion of the head researcher is that eyelashes help protect the eyes from drying out. Also, the best eyelash length is one-third as long as the eye's width. The ratio of eyelash length and eye width was one-third for many mammals.

Researcher Dr Hu started his research after his daughter was born. He wondered why she kept on batting her eyelids. He said: "Eyelashes around the eyes in mammals have always been a mystery." There are a lot of opinions, from catching dust to making people blink. He said it was the first aerodynamic study of eyelashes. It used three different ways to show eyelashes reduce evaporation of the eye by 70 per cent. They also reduce dust in the eyes. Hu has a talent for, "looking at what everybody has looked at, and seeing what nobody has seen."