Disappearing Squirrel

Today I found some squirrel parts lying in the woods.  A red fox had killed a gray squirrel and had done a pretty good job eating it, leaving just the tail (left), the stomach (right, largely covered by a chunk of fur), and intestines (upper right).

At least, I assume the predator was a red fox, based on the scats that were deposited next to the squirrel’s remains.  One (below) was full of apples, and the other was full of wild grapes–no fur or bones–but I didn’t see any evidence that anyone else big enough to catch a squirrel had been by recently.

Of course, as always, there were plenty of smaller creatures in evidence.  Most conspicuous were several types of blow fly (Calliphoridae), which can be seen in both of the photos above if you look closely.  Here is a group of them savoring the stomach:

There was also a big blackish one, about twice the size of the shiny green ones:

Several other, smaller flies of various sorts came and went.  A downy yellowjacket (Vespula flavopilosa) stopped by periodically, attracted to a few drops of blood on the leaf litter.

There was also a steady trickle of spine-waisted ants (Aphaenogaster) carrying off pieces of squirrel and stomach contents.

The whole time I sat there with the squirrel parts, the stomach was moving around in ways that couldn’t quite be explained by the ants that were coming and going from it. Occasionally I could glimpse something like this:

It was a type of carrion beetle (Silphidae) called the tomentose burying beetle (Nicrophorus tomentosus).  Burying beetles excavate the earth under a small carcass (or, apparently, a piece of a larger carcass) until it is completely buried, then work it into a ball. The female then lays eggs, and when they hatch, both parents stick around to regurgitate partially digested meat for the larvae to eat.  In addition to protecting themselves and their offspring from predators, burying their meal helps keep it from drying out and keeps the flies off it. Because eating a maggot-filled corpse would just be gross.

At one point one of the beetles emerged from under the stomach for long enough for me to get a clearer shot of it:

This photo, in addition to showing what fancy-looking beetles they are, shows some of the mites that are often seen scrambling all over their bodies.  It looks like they might be a bit annoying, but this is actually a mutualistic relationship.  These mites belong to a species of Poecilochirus (Parasitidae), and they ride carrion beetles from one carcass to the next.  When they arrive, they eat fly eggs and larvae, reducing competition for the beetles’ food.

I’m sure there was more to see here, but you can only lie on the ground next to a carcass for so long.