Who's the culprit?

  

This is a scene we came across after finishing field work this morning (9 May 2024).  Some empty-looking whelks (Nucella ostrina) on the sand...and upon closer inspection, their opercula nearby (the operculum is the "trap-door" on the bottom of a snail's foot that seals the opening to its shell when the snail is pulled in).

It looked like the snails had been eaten by a predator, but we couldn't recall seeing this before, so we looked around a little more.

We found even more evidence that something had been eating both whelks and limpets.  Here are a few examples, including snail shells and overturned limpet shells with most of the soft parts missing, but with a thin ring of tissue, evidence that they had been eaten recently:

 

 

So...who was responsible for eating these snails and limpets?

 

We weren't sure, but we kept looking, and Eric eventually spotted a clue.  Tracks in the sand around some of the predated shells:

 

 

 

After thinking through the possibilities, we're guessing these footprints might belong to a rat (!).

 

Rat predation on intertidal invertebrates has been documented previously (Thanks to Sergio!), but we don't recall seeing it locally before.  Maybe because there was a lot of sand at this site it was easier to notice the empty shells and the tracks in the sand.

 

Here's a close-up of one track in case anyone can help us with an identification.  The track was ~1 cm across.

 

 

 

You learn something new every day!

Packrat?

So I've been trying to identify a rat.  I don't have much experience identifying rats, but perhaps you can help.

I was driving home from Sebastopol along Occidental Road and noticed a small mammal (dead) in the middle of the road.  I wasn't that interested in leaving it there to be run over by cars, and I was also curious about what type of mammal it was.  So I pulled over and walked back to move it off to the side of the road.

Before departing, I took a few quick photos for the record.

When I realized it was some type of rat, I looked up the main differences between a Norway Rat (Rattus norvegicus) and another species that I know occurs in this area, Dusky-footed Woodrat (Neotoma fuscipes).

Some differences between them include the following: (1) Norway Rats are grayer underneath, while woodrats are paler; (2) Norway Rats have tails shorter than their body lengths, while woodrats have tails longer than their bodies; (3) Norway Rats have "naked" tails with obvious scales, while woodrats have furry tails.

Here's a series of pictures of the small mammal I found on the road.  I should warn you — although this rat is in good condition, if you don't want to see images of a road-killed mammal, look no further.

 

 

 

 

 

This rat's body was about 7 inches long and its tail was about 9 inches long.  It was pale underneath.  Its tail was furry.  These characteristics made me lean towards this being a Dusky-footed Woodrat.  However, I was bothered that the hairs on top of the hindfeet didn't appear that "dusky."  Does this character vary?  Or am I wrong about this identification?  Let me know what you think.

P.S. Dusky-footed Woodrats are also known as "packrats."  They build intriguing houses and are famous for collecting all sorts of trinkets.   The National Wildlife Federation has a basic fact sheet about them here.