Start with three questions, in this order: how many toes registered, are there claw marks, and what shape is the heel pad. Maryland’s Department of Natural Resources sorts nearly every common mammal on those alone. Only then measure the print, and only then read the trail.
That sequence is not arbitrary. The Maryland key opens by asking how many toes the animal has on each foot, whether claw marks are visible, which foot is larger, what the general pad shapes are, and the total length and width of each print. Those five questions run the whole key, and the top-level split is toe count: two toes with occasional dewclaws, four toes, four in front and five behind, or five on all four feet. Get that one number right and you have already thrown out three quarters of the candidates.
Everything below follows that order. The measurements are quoted from the agency that published them, and where two agencies give different figures for the same animal, both are here, because the difference is real.
What does the toe count rule out?
Maryland’s four groups are worth memorizing because they are quick. Group A is two toes with occasional dewclaws, which across most of the eastern United States means deer. Group B is four toes per foot: the cats, the dogs and the rabbits. Group C is four toes in front and five behind, the rodent arrangement, covering groundhog, gray squirrel and muskrat. Group D is five toes on every foot, and that is where opossum, black bear, beaver, raccoon and river otter live.
A partial print is the common case, and Maryland says so plainly: most of the time, the tracks you find will be overlapping and incomplete. Walk the trail until you find one clean print rather than working from the first one you see.
Do claw marks mean a dog or a cat?
This is the single most reliable field mark in the whole subject, and it is free. The U.S. Fish and Wildlife Service puts it in one line: claw imprints are left by dogs and their wilder cousins, meaning coyotes, wolves and foxes, and not by cats.
The National Park Service adds the structural reason and a second check that survives bad substrate. Cats have retractable claws that may not appear in the track at all, and although felids have five toes, only four register. The shape is the giveaway: NPS describes felid tracks as round overall, with a palm pad making up at least half the total track size, and says those two features are what distinguish cat tracks from dogs. Canid tracks run the other way, more symmetrical than a cat’s, longer than they are wide, with a triangular palm pad and four toe pads showing claws.
There is even a signature in the empty space. NPS notes that the negative space in a canid track usually appears as an X shape for red fox and an H shape for coyote, which is worth looking for once a print is clean enough to deserve it.
How do you measure a print so the number means something?
Measure the print at its longest and its widest, which is what Maryland’s key asks for, and measure a front print and a hind print separately, because in carnivores the front foot is usually larger than the hind.
Then measure the trail. NPS defines stride as the distance from the front of one foot to the front of that same foot as the animal travels, and trail width as the distance between the outermost tracks. For animals that move in groups of four prints, it adds group length, from the back of the last track to the front of the first in the group. Those three numbers are how a tracker separates species whose individual prints overlap in size.
What does the trail pattern tell you?
Maryland sorts patterns into four families of movement. Diagonal walkers, which are the cats, dogs and hoofed animals, move opposite limbs together, right foreleg with left hind leg. Bounders, most of the weasels, hop in a steady series of jumps with the forelegs first and the back legs pulling in right behind. Gallopers, most rodents and rabbits, hunch down and bring the hind legs in front of the front legs. Pacers are the wide-bodied animals, raccoons, opossums, bears, beavers, porcupines, badgers and skunks, and they shuffle along, shifting from pacing to bounding as they speed up.
The Fish and Wildlife Service shows what that looks like on the ground. A raccoon’s pacing leaves side-by-side tracks in which each pair is a front paw alongside a hind paw, alternating sides. A snowshoe hare, a galloper, plants its front paws and then brings its hind legs up beyond them, which is why the big prints land ahead of the small ones.
NPS adds the terms for how the feet land. Direct register means the hind foot lands on top of the front track; overstep means it lands ahead of the front foot on the same side. A coyote shows both, plus a side trot, depending on its speed, which is how one animal leaves three different-looking trails in a morning.
Which animal made it, by size?
Here is where the published numbers do the work. These are starting points for the species guides, not a substitute for them.
Maine’s Department of Inland Fisheries and Wildlife puts a white-tailed deer track at 2.5 to 3 inches (6 to 8 cm) and a moose at 4.5 to 5.5 inches (11 to 14 cm), which is the cleanest size split in the two-toed group. The details for each are in the deer tracks guide and the moose tracks guide.
For the dogs, Maryland describes a coyote print as oval and approximately 2.5 inches long by 2 inches wide (6.4 by 5 cm), while Maine gives a coyote front track of 2.5 inches (6.4 cm) and a hind of 2.25 inches (5.7 cm). NPS measured Cascades coyotes at a front track 2 1/8 to 3 1/8 inches long (5.4 to 7.8 cm). Gray wolf front tracks in the same NPS guide run 3.5 to 5 1/8 inches (8.9 to 12.8 cm), which is a different animal entirely once you have a tape on it. Both are worked through in the coyote tracks guide and the wolf tracks guide.
For the cats, NPS gives a mountain lion front track of 3 1/8 to 4 inches (7.8 to 10.1 cm) against a bobcat front track of 1.5 to 2.25 inches (4 to 5.7 cm), and Maine lists a bobcat at 1 7/8 inches (4.8 cm). Maryland’s key splits house cat from bobcat at a front track of 1.5 inches long and 1 3/8 inches wide (3.8 by 3.5 cm), under which it is a house cat. The mountain lion tracks guide and the bobcat and mountain lion comparison carry that further.
In the five-toed group, Maine gives a black bear hind track of 7 inches (18 cm) against a front of 4.5 inches (11 cm), and Maryland’s key routes any five-toed front track over 4 inches (10 cm) with an unwebbed hind straight to black bear. See the bear tracks guide. Raccoon is the other one people meet constantly: Maine gives a front track of 2 inches (5 cm) and a hind of 2.5 inches (6.4 cm), Maryland identifies it by toes that are slender, bulbous on the ends and lacking webbing, and the Fish and Wildlife Service describes five long finger-like toes usually connecting to a C-shaped palm pad. That is the raccoon tracks guide.
Why does snow lie to you?
Because it moves. Maryland says the best tracks are in mud, soft soil or sand, and warns that snow can melt and make tracks appear larger than they naturally are. Maine makes the general version of the point on its card: depending on the substrate and the speed the animal was moving, tracks may show great variability in their appearance. NPS gives a concrete case, noting that a bobcat’s toes can splay widely in deep snow and give the appearance of a larger track.
So a snow print is a lead, not a measurement. If the trail crosses mud or wet sand, walk to it and measure there. Fresh, shallow snow over a firm surface is the exception, and the best tracking of the year.
What a track cannot tell you
It cannot give you a species with any confidence when the print is partial, melted out or splayed, and no chart will change that. It also cannot be read by this app: Animal Identifier works from a photograph of the animal itself, taken with the camera or picked from your gallery, and returns the species with its Latin name, habitat, diet and behavior along with a match confidence. It does not identify tracks, scat or sounds. For the sign itself, the field-sign guides carry the agency measurements and the lookalikes side by side, and when the animal is actually in view, even at distance, what animal is this is the faster route.
Take the track photo anyway. One frame straight down with a coin beside it and one wider frame of the trail let you compare against an agency guide later, instead of relying on memory of a shape you saw once.
Sources
- Guide to Common Mammal Tracks, Maryland Department of Natural Resources Wildlife and Heritage Service
- Pocket Guide to Maine Animal Tracks, Maine Department of Inland Fisheries and Wildlife
- Carnivore Tracking in Washington's National Parks, National Park Service, Mount Rainier National Park
- Snow Tracks, U.S. Fish and Wildlife Service