April 2023 Natural Mystery Answered

Last month’s natural mystery was a question on the most recent Cuyama, CA, Track & Sign Specialist Evaluation. On the eval, participants were able to see the full track pattern to help with the ID. You just had this single track to go on—which was clearly enough for many of you. Congratulations to Adrian Iacovino, Mike Holtz, Alan Holzer, and Kirsten Welge for correctly identifying both who and which foot left this track.

This is the front right track of a Black-tailed Jackrabbit (Lepus californicus).

Mike starts us off with this concise statement: “[here] we have a front foot of a lagomorph, where toe 3 is leading (to the left in the image).”

Leporid tracks can be challenging to identify. The dense fur on the feet obscures the pads and long, flexible toes show a wide range of presentations. On top of this, we often identify leporid tracks from the track pattern. Because of this, we may pay little attention to their track morphology. Alan didn’t recognize the track at first, and his process offers us some good tips for dealing with unfamiliar tracks:

"At first this track was so baffling I couldn't even figure out which way the animal was going.  I first flipped through Elbroch's book to see what tracks were in the right size range, and did a little research to see which animals are found in the area. This give me some animals to look into a little more. I ruled out canines and felines because the placement of the toes and lack of palm pad didn't match. I ruled out anything with hooves, as well as weasels (not round enough) and large rodents. This lead me to look up jackrabbits, and I found several of Kim Cabrera's photos that looked like a match, with a very pointy leading edge."

Adrian took a different approach, beginning by creating a list of candidates:

“Starting with a master species list of mammals that live in Los Padres National Forest that would fit these measurements I had three top guess: Bobcat (3.5-6.7 cm), Western Coyote (5.7-8.3 cm), jack rabbit (4.8-6.4 cm). The overall shape of this track is asymmetrical which rules out canine tracks. It is oblong not circular, which rules out feline tracks. To my eyes, the protruding triangular digit at the front of the track is the salient feature of this print. This creature is moving right to left in the image, which is evident because of the claws registering in the leading edge of this track.”

Kirsten began her analysis by interpreting the morphology. Her description suggests that she immediately recognized this as a leporid front track:


She then narrowed the track-maker down to species by noting: “In this region, the leporids are desert cottontail and black-tailed jackrabbit. The front track length of 1 7/8” is outside the noted range for desert cottontail, but within the low end of the range for black-tailed jackrabbit.”

Each of these trackers gave us some good tips for distinguishing this as a right front print as well. 

Alan invited us to look at the “J-shape of toe arrangement with the longer side of the J on the outside.”

Mike describes the arrangement this way: “Toes 4 and 5 curve around the top of the image, and toe 2 is closest to the point of the popsicle stick.”

Kirsten gives us this explanation:

"The high asymmetry of four indistinct, small, and deep toe impressions points to a leporid front track. (In the leporid hind track, the toe arrangement is more symmetrical and resembles a tiny canid track, but with more space between toes 3-4.) The deep compressions are toes 2-5: Toe 2 is at the tip of the orange arrow. The possible shallower, smaller compression is toe 1."

And Adrian offers these notes:

"What stands out to me in photos is that toes 4 and 5 are stacked on top of each other in jackrabbit front tracks. I see that same stacking in the lowest digit in this photo, between 3 and 4 centimeter marks on the ruler. Additionally, the front feet of black-tailed and white-tailed jackrabbits have a tiny digit (toe 1) called a pollox. The pollox is a clawed toe that sometimes registers and is often blurred by the furry feet of the jackrabbit. There may be a touch of the pollox present at ruler mark 3.9 cm just below from where the orange arrow is pointing."

The term pollux was new to me. I learned that it refers to toe 1 on the front foot. Our thumb is our pollux. The term hallux, which I have gotten to know well studying bird tracks, refers to toe 1 on the hind foot. Our big toe is our hallux, as is the rear-facing toe of many bird tracks. I hadn’t realized that there was a different name for toe 1 on the front. "

Congratulations again to Adrian, Alan, Mike & Kirsten, and thanks to all four for sharing their process with the rest of us.

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