Color-changing critter
I really am fascinated by the “uncommon” or different kinds of critters. I really like the kind of critters that are not like other animals and stand out with a specific feature or uniqueness. Which brings me to several encounters I had with a very cool and different kind of animal on my recent photo tours in Yellowstone National Park this winter.
The Long-tailed Weasel (Neogale frenata) is one of those incredibly interesting critters that you hear about but rarely see or get a chance to interact. This animal is also known as the Masked Ermine, or just Ermine. It is often mistakenly called Stoat. The Stoat is the Short-tailed Weasel (Mustele erminea) and is very similar but smaller and has a shorter tail.
In summer, the Long-tailed Weasel is brown with a whitish belly. The tail is also brown and has a distinct black tip. But one of the things that makes this critter so cool is they turn all white, except for the tip of the tail, which remains black during winter. To add to this coolness, the Long-tails in southern regions don’t turn white in winter, and the ones in the transition zone only turn partially white. This is an example of extreme adaptation to their environment. This adaptation is called erminism. The process of changing colors is triggered by the amount of available daylight. As the days get shorter in fall, the weasel produces a hormone called melatonin, which suppresses melanin production and causes the new growing fur to not have its normal coloring and as a result is white. In spring, the hormone process reverses, and the newly growing fur is brown.
The Long-tailed Weasel is a predator, make no mistake about that. They are an aggressive hunter, constantly moving around looking for the next meal. Hunting mostly small mammals, such as mice and voles, they will also hunt animals up to the size of a rabbit. They are technically called an obligate carnivore, which means they don’t scavenge from dead animals. They are true hunters.
Occasionally, they will hunt small birds, especially ground-nesting species, but it’s not unheard of for these weasels to climb trees. In fact, they often climb trees when they are being pursued by larger predators, such as fox, coyote, and bobcats. And yes, some small predators are hunted by larger predators.
The Long-tailed Weasel dens in underground burrows, inside rock piles, under tree stumps, but mostly in burrows made by other animals. They do not dig their own burrows. They also don’t use a burrow for very long. They have a nomadic lifestyle that is dependent upon their prey. One of their favorite burrows are that of chipmunks. They fit right inside and often use the fur of their prey to line the nesting chamber within.
They are a member of the weasel family, which means they have a well-developed scent gland, which produces a very strong and musky odor that is similar to skunks. Unlike skunks, weasels can’t spray their musk, but rather, it rubs its scent glands over surfaces, like rocks and logs, which leaves the strong odor behind.
During my photo tour of Yellowstone this winter, I found three Long-tailed Weasels over a three-week period. Just a side note, seeing just one is amazing. Nearly all encounters with Long-tailed Weasels are usually super quick. Often, you see one running and jumping and then it’s gone, within a matter of seconds. The first two encounters were just like that; saw them for a split second and then disappeared. But the third encounter was slightly different. The weasel was running across the road and dove into a snowbank. And just like that, it was gone, but then it popped up out of the snow and took off across the road again. This time, it jumped over the snowbank at the road’s edge and ran to the base of a fallen branch, where it paused for just enough time to capture a few images.
As funny as it might sound, this brief but exciting encounter with the Long-tailed Weasel was one of the highlights of this year’s winter trip to Yellowstone, even though we had many encounters with wolves. Until next time…
Stan Tekiela is an author / naturalist and wildlife photographer who travels extensively to study and capture images of wildlife. He can be followed at www.instagram.com and www.facebook.com. He can be contacted via his webpage at www.naturesmart.com.
