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short-tailed weasel in the Keith White Prairie

Short-tailed weasel (Mustela erminea), Family Mustelidae, just before he bounds off into the Keith White Prairie. Click on the photo to see a larger image


UW Green Bay biology student Amanda Malueg is trapping small mammals in the Keith White Prairie as part of her Cofrin Arboretum Student Research Grant. She is investigating the effects of fire in prairie management, and earlier this year Amanda and other students participated in the controlled prairie burn that allowed her to set up her experiment. So far Amanda and her field team have caught 4 Short-tailed Weasels (Mustela erminea) in the prairie on the southern portion of the Cofrin Arboretum. The photo shows one of the weasels before it was released back into the prairie.

Notice that this short-tailed weasel caught in October still has its summer fur color. Our eco-note of a short-tailed weasel caught in January of 2002 shows the white winter coat color. Soon this weasel will shed his brown fur and grow a white winter coat that will blend in with the snow covered landscape, offering it camoflage from predators as well as prey. Decreasing daylength triggers changes in chemicals released by the pituitary gland that stimulate the beginning of fur shedding or molting. These chemicals inhibit the release of colored pigment into the hair, so the hair is translucent or white rather than brown. Temperature also affects molting by altering the speed it takes the coat to change from summer to winter coloration, so that if it suddenly becomes and stays colder the shedding process occurs more quickly. Molting generally begins in October and is complete by early December. While it is shedding a short-tailed weasel will have a mixed brown and white coat. It will molt again to its summer coat as daylength increases between mid-March and late April.

More information on weasels can be found on our econote of 20 January 2002

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Last updated on April 15, 2014