If every buck in your woods and fields drops their antlers every winter, why isn’t the landscape littered with them? Why haven’t you walked a few steps into the trees and found not only this year’s shed antlers, but last year’s, and those from many years past? It’s not your poor eyesight. If you are a seasoned shed hunter, you might already be thinking “Darn squirrels!” – and you would be right!
Squirrels and other rodents including mice, rats, voles and porcupines often snack on shed deer antlers. This behavior is called osteophagy – consuming bone – and is witnessed in many animal populations around the world.
The Rodent Diet
Squirrels are opportunistic omnivores, and their diet consists of a variety of plant and animal material. In a 1981 report, Leroy J. Korschgen of the Missouri Department of Conservation studied the stomach contents of 1,266 fox squirrels and 993 grey squirrels and found they feed primarily on seeds, flowers, nuts, and fruits. They rely on food caches of these items hidden during the fall to sustain them through the winter.
But they’ll also consume fall-back food items such as insects, fungi, bird eggs and agricultural crops. They’ll even capture live prey such as frogs, nestlings and adult birds. This variety in their diet allows for a variety of nutrients and minerals to keep them healthy.
Gnawing Shed Antlers for Nutrients
Antlers can offer an easy opportunity at some additional nutrients and minerals, especially for certain squirrels at certain times of year.
Antlers consist of 11 different mineral elements. When hardened they contain roughly equal parts protein and minerals with the majority of these minerals consisting of calcium (19%) and phosphorus (10%). A University of Georgia study tells us that the other minerals include magnesium, sodium, potassium, barium, iron, aluminum, zinc, strontium, and manganese. It is suspected that the need for these additional minerals in their diet is what drives squirrels to chew on cast antlers and other bones.
Out of all these nutrients, calcium and phosphorus are most likely the main dietary goals for gnawing squirrels. Several studies have noted that these two elements may be especially beneficial for female squirrels. In a 1993 study, J.R. Callahan of the University of New Mexico noted that lactating female squirrels gnawed on bone (including antlers) more often than non-lactating squirrels during the late winter and spring months. It seems deer antlers are hitting the ground right when female squirrels are answering the peak nutritional demands of late-stage pregnancy and nursing their newborn young.
Never-Ending Gnaw
Squirrels have other reasons to enjoy a shed snack. For one thing, they are able to wear down their teeth using this method. All squirrels have four long, thin incisors at the front of their jaw with two on the top and two on the bottom. These incisors have a specialized enamel coating that will continue growing throughout life. These types of teeth are called elodonts, which means “ever-growing teeth.” Elodonts can take the daily wear and tear of a gnawing lifestyle without permanent damage or requiring tooth replacement. Several other familiar animals also have “ever-growing” teeth including most rodents, rabbits and ferrets. These small animals share this characteristic with some much larger mammals as well including elephants and hippos who both present elodont incisors as their tusks!
Squirrels gnaw with their specialized ever-growing teeth by either holding the cast antler in place with the maxillary (top) incisors while dragging the mandibular (bottom) incisors across the surface or dragging both sets of chiseled teeth across the outer edge of an antler at the same time. This is what leaves behind the divots on a tooth-carved shed.
Although this phenomenon may seem frustrating as we hike through the woods, hurrying to find shed antlers before the squirrels do, it does play an important role in ecology. Without these critters disposing of a good portion of antlers and animal bones, we would have an overabundance of them crowding the landscape.
Imagine the struggle of attempting habitat work as you tripped on cast antlers or – worse – pulled them from ATV and tractor tires. Next time you discover a chiseled shed antler take a minute to be grateful for nature’s clean-up crew – but do your best to find shed antlers first!