Aha! In the North American continent, one can find mention of Microtus
richardsonii, whose common name seems to be "Water Vole". There are also
shrews of the genus Sorex, specifically Sorex palustrus and Sorex bendirii
(common names Water Shrew and Pacific Water Shrew respectively). I know
nothing first hand about these, except I know I don't have them in my pond!
You can Google them and find out more if you desire.

"Cynthia Donahey" wrote in message
...

Is there any reference to the American vole on the web.

They are very small (about one ounce) and native to the northwestern part
of North America. Does anyone have any in their pond? Does anyone know
anything first hand about them?