Oh my! It’s a white weasel in a brown background.
Long-tailed weasels (Mustela frenata), native from Canada to South America, molt twice a year in October-to-mid-November and March-to-April. Those who live in the north turn white, the rest of them stay brown. Here’s what they look like in summer.
On October 30 in Calgary, Alberta, Dan Arndt easily found this long-tailed weasel checking out the scenery near Fish Creek Provincial Park. The weasel had turned mostly white though his back was still pale brown (see below).
Long-tailed weasels are fearless and aggressive, able to kill animals larger than they are, but they’re small enough to fall prey to large mammals, hawks and owls(*). Camouflage is important. Their fur is meant to hide them as they hunt and are hunted.
This weasel turned white right on time but there’s no snow to hide him. The first frost usually occurs in Calgary on September 16 and it snows 3.9″ (10cm) in October, but not this year. The high was 54oF (12.2oC) on the day these pictures were taken.
It’s likely that climate change will change northern long-tailed weasels. They’ll probably still molt in October-to-mid-November but without snow to hide them the whitest ones won’t survive. I expect the population will be browner in Canada a century from now.
In the meantime, this one looks annoyed that he’s attracted attention now that he’s put on his winter coat.
(photos by Dan Arndt)
(*) Long-tailed weasels are 12-14″ long but their tails make up 40-70% of their length. Thus their bodies are only 4-8″ long.