Deer have Adapted for Winter

deer at CR camp
Mule Deer in the Crooked River Campground on a cold, wet, morning.

Mule Deer (Odocoileus hemionus) are native to western North America and are one of the most commonly seen animals at The Cove, especially in the winter when visitation is low.  I was talking to a young park visitor the other day and he asked, “Do deer get cold when it snows?”  And I thought, what a great question to write about!

Deer have wonderful adaptations to survive in the high desert’s frigid winter temperatures.

Mule Deer, Photo credit ronjbaer

First of all, most deer don’t live in the same place all year.  They move to winter ranges in lower elevations, where they can find more nutritious foods when it gets cold.  They are commonly found on warmer south facing slopes with less snow cover.  This is smart because when there is more than eleven or twelve inches of snow, it’s hard for them to move around.  In fact deer typically won’t stay in area that has more than a couple of feet of snow for a prolonged period.  They prefer forests with plants of different sizes for cover from predators, thermal protection and snow interception.

Mule Deer foraging, Photo credit, Ron Stewart, Utah Division of Wildlife Resources

Deer are always eating.  Fall grazing for deer is full of high energy plants, seeds and nuts that allow them to fatten up for winter.  When winter comes, deer move around less to conserve energy and browse (eat) woody plants that are easy to digest like sagebrush, bitterbrush and rabbitbrush.  Their metabolism falls to half of what it is in summer, so the fat stores last longer.  If you have deer in your yard, it’s better not to feed them.  Oregon Department of Fish and Wildlife discourages feeding wildlife as deer can only digest wood browse, and the extra energy used to go to and from the artificial food sources can actually exceed the energy they would get from it – making them hungrier.

mule deer fur

Just like people, they have a winter wardrobe.  Their thick winter coat has hollow guard hairs, like polar bears, and fine hair under the guard hairs act like a fleece jacket and insulate them from the cold.  The dark color of their fur absorbs the suns heat and helps keep them warm.  Also in extreme weather, deer experience horripilation  or “goose bumps” like we do.  This occurs when skin tightens up and traps a layer of air near the skins surface which helps keep it warmer.

As you fulfill your new years resolutions to get out and exercise, find a park and marvel at how amazing our mule deer are.  Be sure to educate your children not to scare them though.  If deer get scared and run, it just uses up necessary calories they need to stay warm.  Continue reading “Deer have Adapted for Winter”