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Do You Know Scat?

In many areas of Wyoming and the West, good bighorn sheep winter habitat is also mule deer winter habitat. If you have ever been out exploring in these areas, you may have noticed the "calling cards" these animals leave behind. Wondering which species has been in the area? Here are a few details to look for when examining these pellets.
Our thanks to Bruce S. Thompson, a member of our Board of Directors and a skilled naturalist for providing the following information.


1. Winter / dry forage droppings are most reliable for ID, since the variables of food types, food moisture and animal age stratification are much reduced from that of spring and early summer. Most of what follows pertains primarily to winter / dry forage specimens.

2. Anyone who claims to be able to tell bighorn scat from mule deer scat 100% of the time without the added clues of location, specimen age and associated sign is, uh, full of it. I try for 90% accuracy if I'm going to claim the ID of a specimen. As the great naturalist / scatologist Olaus Murie once said, "I'm never absolutely certain unless I actually see who it dropped from."

3. Tendencies of dry forage / winter bighorn scat: (a) tends to be more coarse than mule deer; (b) the pellets from a single pellet group of bighorn tend to be more variable in size and shape than those from a single pellet group of mule deer. (See illustrations, below.) Note that these are tendencies, not absolute consistencies.

4. Spring scat clusters, resulting from moister forage, tend to look more like flattened wafers from bighorns, more like clusters of small pellets from mule deer.(See illustrations, below.) Note again that these are tendencies, not absolute consistencies.

a. (Below) Bighorn Sheep winter pellets collected from Torrey Valley:

Various characteristics of sheep scat and deer scat.

(1) The specimens Above Left demonstrate the variability of pellet shape from a single bighorn pellet group.

(2) The specimen on the Above Right were older with mold when collected and are from multiple pellet groups, but demonstrate the wide range of pellet sizes and shapes collected in the same area.

(3) The specimens Above Center show the "clustered wafer" shape more common to bighorn sheep when consuming moist forage in spring and early summer.

For comparison, here's a late spring cluster specimen from mule deer (notice the identifiable pellets):

detail of mule deer scat

B. (Below) Winter / dry forage mule deer pellets tend to be of a somewhat finer texture and more uniform in size and shape, as shown with these from this single pellet group collected in Kelly, Wyoming:

detail of mule deer scat on a winter diet

C. The specimens below are all from mule deer. Notice: (a) how even mule deer have a lot of seasonal variation to scat color, texture, size and shape; (b) however, the mule deer still remains quite consistent in shape and size within a given pellet group; (c) the specimens on the lower left and lower center, below, are very coarse, tending to resemble a small moose pellet, demonstrating wide variability due to variable forage type and moisture content.

more detail than you really wanted about mule deer scat

Final thoughts: As long-time friend and fellow tracker Jim Halfpenny likes to say, "Never say never, and always avoid always."