Thursday, February 7, 2013

A Track in the Sand

A track in the sand on North Manitou Island, Sleeping Bear Dunes National Lakeshore
I have looked at track identification in two other posts: one on mouse tracks and another on White-Tailed Deer tracks.  Knowing some characteristics about certain types of tracks can help us identify the animal that made them.  Sometimes you get lucky and find a series of tracks and can learn things such as the animal's pattern of movement, the length of its stride, or the width between its tracks  Other times you only find a single track.  If that is the case, there are still several questions that you can ask yourself.

  • What shape is the track?
  • How many toes do I see?
  • Are the toe nails visible in the track?
  • What habitat is it in?
  • How deep is the track?
  • Is there anything else unique about the track?
  • Could this track be from a domestic animal?

(One note- this track was found on North Manitou Island, part of Sleeping Bear Dunes National Lakeshore.  There are no domestic animals on this island so the track had to have been made by a wild animal.)

The first thing to notice about this track is its shape- roughly an oval. Second, count the number of toes.  There are four toes visible on this track.  Those two clues give a big jump start toward identification.

A mammal with an oval track and an even number of toes will move with a walking motion.  Walkers have skinny bodies and long legs. Their footprints will generally be in a straight line with a narrow straddle between the tracks.  Because their feet are small for their size they will generally leave deep footprints as their weight is concentrated in a small area. 

In Michigan, there are currently 10 species of wildlife that move with a walking gait: three members of the cervid (deer) family, three species of felines (cats), and four species of canines (dogs).  We can immediately rule out this track as belonging to a member of the deer family - tracks of White-tailed Deer, Elk, and Moose would all show only two toes.

So that leaves the members of the cat family and dog family as possible solutions.  One thing that helps decide between whether this track belongs to a cat or dog is the presence of visible marks from toenails.

Toenails are visible on three of the four toes.
The visible toenails tell us that this track is probably not from a feline.  Cats have retractable claws that are not typically visible in their footprints.  Therefore this track must be from a member of the dog family.

An X fits between the toes and heal pad
There is one more clue that tells us this a dog footprint and not that of a cat.  On a dog footprint, you can draw an X between the heal pad and 1st and 4th toes.  On a cat footprint, one or more of the lines of the X would cut across one of the toes.

So which member of the dog family is it?  There are four possible options in Michigan: the Gray Wolf (Canis lupus), Coyote (Canis latrans), Red Fox (Vulpes vulpes), and Gray Fox (Urocyon cineroargenteus).  The Gray Wolf can be eliminated immediately.  A wolf track is usually between 4 and 5 1/2 inches long.  This track is too small and it was found in a location outside the wolf's current range.

The remaining three species are all a possibility, but we can eliminate the Red Fox fairly easily.  The size of this track is right for a Red Fox (2 - 3 inches long), but a red fox track has a horizontal or curved bar that runs across the heal pad.  This is absent in this track.  Also Red Fox feet are very hairy and their track is often obscured by the hair.

This leaves the Gray Fox and Coyote as possible options.  Size is usually enough to distinguish between these two.  Gray Fox tracks are usually between 1 1/4 and 2 inches (3 - 5 cm) long.  Coyote tracks are between 2 1/4 and 3 inches (5.5 - 8 cm) long.  There is nothing in this photo to indicate scale.  That makes it difficult to tell which animal made the track, but the track gives us a clue. 

On a Gray Fox track, all four toenails are typically visible.  On a Coyote track, only the middle two toenails are usually visible.  On this track we can see the toenails on the first, second, and third toe.

Note that the track is deeper in this section
If you look at this track closely, you will see that the upper portion of the track has left a deeper impression than the lower portion.  This track was made on a slight slope and the impression was deeper on the uphill side of the track.  On a level surface, the toenail on the first toe would probably not have been visible; we would only see the toenails on the second and third toes.  This gives us our identification.

This track is from a Coyote (Canis latrans).

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