Can
you identify what's in this photo?
Each Wednesday morning
on Camp Lutherlyn's Facebook page
the Lutherlyn Environmental
Education Program posts a photo.
Readers
have all morning and afternoon
to
make their best guess about what the photo is.
Around
6 pm LEEP provides the answer and a brief explanation.
Each
week's What is it Wednesday post
will
also be posted on the Nature of Lutherlyn blog,
after it is posted on Facebook,
sometimes
with additional bonus information.
In
addition to bringing you current editions of What is it Wednesday
on the
Nature of Lutherlyn blog,
we
will be reposting old editions,
creating
a What is it Wednesday archive.
This photo was posted as a What is it Wednesday on
January 5, 2022.
And
the answer is....
These are tracks left behind by either slugs or land snails.
What we are seeing is where they have traveled across the bench and eaten the
thin layer of algae that is growing on the surface of the wood.
This explanation from “Tracks and Signs of Insects and Other
Invertebrates,” by Charley Eiseman and Noah Charney, helps us understand how
this track is made: “Like other mollusks, slugs and snails possess a radula, a
straplike organ inside the mouth that is covered with many small, sharp teeth.
As the animal slowly glides across the surface, it moves its head from side to
side while scraping up algae with its radular teeth.”
The reason why the tracks look so “squiggly” is from the
motion of the head side to side as the snail or slug travels along its path.
With a closer look, you can make out tiny narrow lines within each track –
these are the teeth marks. (It is hard to see them in this photo, and getting a
closer view makes them blurry, but you may be able to see the little lines within each squiggle.)
The only difference between slugs and land snails is that
snails have shells and slugs do not. Check out this previous What is it
Wednesday to find out more about these fascinating little creatures: https://lutherlynnature.blogspot.com/2020/06/what-is-it-wednesday-june-24-2020.html
Keep an eye out and maybe you will find tracks like these or
other intricate signs that animals leave behind as they go about their lives!
