November 2024 Natural Mystery Answered
Last month’s natural mystery was extra special for me. This was the first time I had ever identified the tracks of this particular species in the field. Congratulations to Collin Arnett for successfully identifying these tracks to family (which was what I was looking for), and to first time contributor Leslie Mills for correctly identifying these tracks to species.
These are the tracks of a star-nosed mole (Condylura cristata)
Let’s hear about how Collin and Leslie approached identifying these tracks. We’ll start with Leslie:
“The first thing that caught my eye was the distinctive crescent-shaped arrangement of the tracks that suggested the toes of this little critter were turned inward. Having recently been playing several games of solitaire with the Animal Tracks playing cards, I remembered noting tracks with a similar pattern. So I pulled out the deck of cards and flipped through them, scanning the edges of the cards where the gait pattern was laid out, until I found a match with the Three of Clubs, which confirmed the tracks matched ‘Moles’ at a cursory glance.”
Collin’s approach was similar:
“My first hit on this was some kind of frog, particularly with the neat, slightly-arcing line of dots. But I also see a fairly clear print straight down from the number four on the reference ruler that looks like a mammal track with four clearly visible toes. I knew there was a track with puncture marks like this that I hadn’t seen before outside of a reference. In trying to jog my memory I scrolled through Jonah Evans’ iTrack app (which includes one front and rear track on its overview) and hit on moles.”
One of the great things about flipping through field guides or similar resources is that we see images of a variety of tracks again and again and again, building up search images in our minds. Despite never having identified mole tracks in the field, both Leslie and Collin recognized this pattern as something they had seen in a reference, and knew exactly where to look to find a match. From here, each of them dug in deeper to confirm the ID and try to get more specific. Collin did this by digging into some field guides:
“Moles have large front feet and claws for digging, and most references note that front tracks typically show only claw marks. I see five marks here. I measure the front “track” or rather the width of the claw marks at 2.1 cm. That fits Poppele’s ‘nail marks’ measurement for Eastern Mole. It falls outside of Elbroch’s American Shrew Mole measurements, though that appears to be the smallest mole in the world [Ed: Elbroch notes that front tracks for larger moles may be as large as 3.1 cm]. It does also fit in Evans’ range for mole ‘track width’.”
Leslie turned to the internet. First to Kim Cabrera’s vast library of resources:
"To confirm that this was what mole tracks would look like in silt/mud, and not just in a stippled image on playing cards, I found a video on YouTube by Kim Cabrera on her beartracker777 channel titled 'Mole Tracks', where she explains what to look for in a trail she followed out of a stream and up a muddy riverbank. The tracks in her video appeared very similar to the ones in this photograph, and were also of similar size. She showed how the spade-like shape of a mole's front foot would leave the larger print compared to its more slender hind foot, and how the angle of the mole's arms was designed for digging and tunneling, which would result in tracks that had the toes pointing inwards. However, Kim's video was filmed in Northern California, and she identified her mole as a Broad-Footed Mole. Broad-Footed Moles are not found in Wisconsin."
And then to regional specific resources:
"In an article titled ‘Mole Control’, Scott R. Craven identifies the moles that live in Wisconsin: ‘There are two species of moles in the state — the common, eastern, or prairie mole (Scalopus aquaticus), found mainly in the western and southern parts of the state, and the star-nosed mole (Condylura cristata) which dwells primarily in the northern half.’
"On The Wilderness Center's website, they have a page dedicated to the Star-Nosed Mole, which says, ‘The preferred habitat of the star-nosed mole is wetlands near streams, lakes and swamps. The soil in these locations is soft making it easier to dig tunnels for moving around and foraging, and deeper chambers for sleeping and nesting. These guys are built for... swimming and diving. The star-nosed mole is the only semi-aquatic mole in the world.’
"I found a blog entry by Andy Dobos on his website The Forest Wolf, where he wrote about his own attempt to identify mole sign in Connecticut based on habitat alone: ‘Each of the three mole species has a favored terrain. Hairy-tailed prefer drier open areas with loose soil. Eastern moles can handle somewhat denser soil and enjoy meadows, your lawn, open woods and similar places. Star-nosed go for low wet places where they can find crustaceans and even small fish and amphibians as well as the worms and inverts the other moles eat.’"
This information led Leslie to conclude that these are the tracks of a star-nosed mole. And I agree. A search on iNaturalist shows no observations of eastern moles within nearly 100 miles of Day Lake. In addition, it is exceptionally rare to see eastern moles moving across open ground in the way this animal was doing. Eastern moles may be the most highly fossorial of all mole species. It is common for an eastern mole to spend its entire life underground, never coming to the surface at all. Star-nosed moles, on the other hand, frequently come out of their burrow systems to forage. As some of Leslie’s resources note, many of these excursions are underwater, but some are overground.
The habitat, range, and behavior are all most consistent with star-nosed mole. As I noted above, this was the first time I have ever identified star-nosed mole tracks in the field. They are uncommon in the Twin Cities Metro Area, and tend to live in relatively inaccessible marshy areas.
To wrap up, let’s hear one final tidbit from Collin:
“Fun wiki-facts: moles have a sensing organ called Eimer’s organ which senses touch. Star-nosed moles have the most developed version of this. A paper in the journal Nature bestowed the star-nosed mole as the fastest eating mammal, able to eat prey in as little as 120 ms. Apparently it can decide if prey is edible within 8 ms which is literally the time it takes to conduct along the neural path! https://pubmed.ncbi.nlm.nih.gov/15690041”
Congratulations again to Collin and especially debutante Leslie. And thanks to everyone who submitted an answer.
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