Dog (Canis familiaris) scat. Image via Wikipedia

Challenges to the Macro Identification of Wildlife Scat and Feces

I have received dozens of photos from individuals wanting me to identify the species that left the scat and feces they have found. Unfortunately, scat is not as specific as a finger print. (Note: recent research has shown that fingerprints may not be as easily tied to a specific human as we think).

Definition: Macro identification of scat refers to the use of a scat’s shape, form, measurements, and context to determine the species that left it. Unlike DNA testing, macro identification lacks certainty.

Feces change from day to day even from the same animal

The fact is scats even from the same animal, let alone representatives of the same species, change from time to time and even from day to day. Don’t believe me? Without trying to be gross, just consider your own droppings. Change your diet and water intake and your scat will change color and form. Get sick, and your scat can become hard or soft.

Measure Scat and Measure Carefully

People usually focus on the length of the scat. It makes sense because length is such an easy characteristic to measure. While length is important, it isn’t anywhere as important as the width of the scat. The length of a scat can change with the fiber and moisture intake of the animal. However, width doesn’t change anywhere nearly as much because the animal’s anus remains relatively fixed in size once the animal reaches adulthood.

Measurements are Only Suggestive

Before you get too excited about the value of measurements, I have to make some cautionary statements. Width of scats change according to the animal’s size. If a raccoon is young, it’s scat will be narrower than if it is mature. This variability means that the best we can hope for is a range of measurements.

Don’t be Discouraged

At this point you might be thinking that scat identification is little more than a guessing game. Not quite. My point is that scat identification is really about ruling out possibilities rather than certainty about what animal left the animal. In other words, it is easier to know what the scat isn’t than to know what it is. You determine what the scat is by ruling out other suspects or in instances where you have multiple suspects, you use context to help say one species is more likely than another.

Stephen M. Vantassel is a certified wildlife control operator and is available for consulting, presentations, workshops, and expert testimony on wildlife damage management related issues.