Whereas dolphins and whales rely on thick blubber to help keep warm in cold water, fur seals and sea otters depend on dense fur to trap a layer of air against their bodies. Since air does not conduct heat as well as water, air layers can insulate against heat loss.

Now mechanical engineer Alice Nasto at the Massachusetts Institute of Technology have created artificial mimics of such fur to see how these hairs protect these seafaring creatures.

"Our research group studies a lot of biologically inspired fluid mechanics problems, such as how snails use slime for locomotion, or how water striders walk on water," Nasto says.

The researchers used laser-cut acrylic molds to fabricate hairy surfaces made of silicone rubber. They next experimented with the effects that hair properties such as hair length and hair spacing had when these materials were plunged at precise speeds into liquids such as silicone oil, which comes in a variety of viscosities.