Strange as it seems, the smallest mammal
Is the shrew, and not the camel.
And that is all I ever knew,
Or wish to know, about the shrew.
Shrews are tiny mammals that have been widely characterized as simple and primitive. This traditional view is challenged by a new study of the hunting methods of an aquatic member of the species, the water shrew. It reveals remarkably sophisticated methods for detecting prey that allow it to catch small fish and aquatic insects as readily in the dark as in daylight.
It is a skill set that the water shrew really needs. About half the size of a mouse, water shrews have such a high metabolism that they must eat more than their weight daily and can starve to death in half a day if they cant find anything to eat. As a result, water shrews are formidable predators ounce for ounce.
Water shrews do much of their hunting at night so I began wondering how they can identify their prey in nearly total darkness, says Ken Catania, the associate professor of biological sciences at Vanderbilt who headed the study.
Catania teamed up with James Hare and Kevin Campbell at the University of Manitoba and used a high-speed infrared video camera to answer this question. The results of their study are reported in a paper titled Water shrews detect movement, shape, and smell to find prey underwater published Jan. 9 in the Proceedings of the National Academy of Sciences.
Our research confirms that shrews in general, and water shrews in particular, are marvels of adaptation, with specializations and behaviors that put many other mammals to shame, says Catania.
The researchers needed a high-speed camera because of the water shrews lightning-fast reflexes: It can launch an attack in under a 50th of a second of detecting the presence of prey and opens its mouth in preparation to take a bite in a 20th of a second. To determine how the shrews hunt in the dark
|Contact: David F. Salisbury|