A galaxy in the spiral of a snail shell
The spiral in a snail’s shell is the same mathematically as the spiral in the Milky Way galaxy, and it’s also the same mathematically as the spirals in our DNA.
The Hills are Alive…
On Sunday, May 7th the tracking group met at the Lockyer Pits in Orangeville for a day of adventuring on rolling sandy trails in the rain. Under the shelter of a roadside edge of trees, we observed snail shells that had been predated. This opened up a discussion on the predators of land snails. Mark Elbroch speaks to this in his book “Mammal Tracks and Sign”:
- Shrews and mice create middens (debris piles) of snail shells under logs and other cover.
- Chipmunks, red squirrels and many others eat snails where they are encountered.
- Mammals usually chew snails from the entrance of their shell and wind their way backwards. Alexis added that they “slurp out” the snails. That makes sense to me.
- Birds tend to move snail shells to an “anvil”, a rock or log that makes hammering into a snail shell easier. They open snail shells from the side, near the top of the spiral.
In looking at the following photos of what we found, it appears that the shells were opened by a bird:
That being said, we noticed two indents at the edges of the spiral and wondered whether they could be from the canines of a mammal. This question led us to investigate the distance between the potential canine marks. They were about 10 mm apart. We referred to byron’s handy “Intercanine Widths” sheet from Mark Elbroch’s “Mammal Skulls” book and worked through the possibilities:
Long-tailed weasel (male): 7.33 – 9.03mm
Mink (male or female): 8.33 – 12.47mm
We recognized that mice have incisors rather than canines. We counted them out. Shrews on the other hand, do have pointy canine-looking teeth but the measurement would be less than 10 mm according to the Skulls book. We also discussed skunks as a possibility but their minimum intercanine width was close to 12 mm. So…if not a bird, then most likely a mink. Wildlife detective work is fun 😊
We get wise by asking questions, and even if these are not answered, we get wise, for a well-packed question carries its answer on its back as a snail carries its shell.
Raspy Cat-like Snail Tongues
Fun fact: Did you know that snails use their raspy cat-like tongue to lick rocks like limestone to get calcium for shell formation? This can wear their tongue away but the radula regrow similar to our fingernails! For more interesting information on snails, please check out the following link:https://www.welcomewildlife.com/all-about-land-snails/
Deer Trail Interpretation and Easter Egg Hunt
Later in the morning, the tracking group used popsicle sticks to interpret a deer trail, noticing its gait slowing down before a berm in the landscape where another deer trail joined it.
Leigh found predated egg shells in the grassy meadow. It was very much like a wild Easter Egg Hunt. Alexis confirmed that they were from Ruffed Grouse and a Wild Turkey. Byron did a really nice write-up on the differences between Wild Turkey eggs and Canada Goose eggs in Saturday blog entry. I recommend reading it if you have not already.
A Sunburst of Lichen
Earlier in the day I was quite captivated by the beauty of Sunburst lichen (Xanthoria parietina). Hmm…what is a lichen? Lichens are a partnership between a fungus and an alga. The fungal tissue provides structure and protection for the algae/cyanobacteria from ultraviolet light and drying out, while the algae/cyanobacteria provides food in the form of sugars from photosynthesis for the fungus. Here is a fun way to remember lichens:
“Annie Algae met Freddie Fungus. They took a lichen to one another. Annie fixes the food while Freddie provides moisture and support. Now their relationship is on the rocks.”
I learned that the Sunburst lichen tolerates higher levels of Nitrogen in the air (compared to other lichens) and can survive in more urban areas. It is often found on tree branches and rocks where birds perch and leave nitrogen-rich droppings. Sunburst lichen is antibacterial and it also makes an interesting dye, which starts off pale pink and turns to a pale blue on exposure to sunlight. Here is an interesting link on making dye from Sunburst lichen: