Winning Whiskers
Wednesday, November 23rd, 2011Nov. 23, 2011
A comparison of the whiskers on a small South American marsupial with those of modern mice and rats have led researchers in the United Kingdom to an interesting theory about the evolution of mammals. Whiskers, say scientists from the University of Sheffield, may have represented an important milestone in the development of the first mammals. The marsupial, called the grey short-tailed opossum, is similar in many ways to an early mammal that lived about 125 million years ago. Scientists believe that the ancestors of modern rodents and marsupials split from a common ancestor several million years before that.
Most mammals other than humans have long, stiff hairs, commonly known as whiskers, growing around mouth or other parts of the head. These highly sensitive touch organs are also called vibrissae or tactile hairs. Around the tactile hairs lie many nerves, which transmit signals to the brain when the whiskers brush against objects. “Whisking” help animals to feel their way through narrow or dark places. It also helps animals, particularly mice and rats, build maps of their surroundings.
A mother opossum carries its young on its back. Baby opossums stay in their mother's pouch for about two months after birth. They remain near her for several more weeks. E. R. Degginger
The University of Sheffield researchers found that both modern mice and rats and the grey short-tailed opossum whisk rapidly from side to side if the animals are traveling in a straight line. As they turn, however, their whiskers follow the turn. If the whiskers contact an object or a surface, the whiskers on the opposite side sweep around to collect more information.
The researchers proposed that the first mammals developed whiskers to help them survive in a challenging environment. At that time, mammals were small, tree-dwelling creatures that hunted at night in the shadow of the dinosaurs that dominated the land areas of Earth. In addition to learning about whisking, the scientists are using their findings to help to develop robots with artificial whiskers that could be used in search-and-rescue operations at disaster sites.
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