The platypus can hunt prey with its eyes and nose closed because it can sense electrical impulses, according to scientists at the Monash University in Victoria, Australia.
In a report in the current issue of Nature, they said they have found that electric charges stimulate specialized receptors in the bills of platypuses. These receptors also respond to the electrical signal given off by the tail flick of a shrimp, which is prey for a platypus, they said.
The platypus is a small aquatic, egg-laying mammal with webbed feet, a tail like a beaver's and a bill like a duck's.
Receptors for electric impulses are known to exist in some fish and amphibians, but it appears that such receptors evolved independently in the platypus, the scientists said.
"Platypuses are common in muddy streams and at most times have eyes, ears and nose shut during a dive, so they probably rely almost entirely on electro-detection to locate prey, and to receive information about obstacles on the stream bottom and variation in the depth of the stream," the researchers wrote.