True Nature Stories: Devil's Coach-Horse Beetle

Devil's Coach-Horse Beetle
(Ocypus olens)

I've been noticing a new neighbor the last few weeks and just learned the sinister-sounding name given to these little black critters (thanks, Bug Guide!). I've seen several of them scuttling across the sidewalk along 36th Avenue and Sunset Boulevard, but nowhere else. The first couple of times I tried to get a phone snap of one of these handsome devils, the beetles made it to cover before I could get the phone out of my knapsack, turn it on, and start the photo app.

Descriptions of this beetle seem to be written mainly by folks on the other side of the Atlantic, where the beetle is common. I was interested in this distribution map showing it throughout Europe and North Africa. Their Wikipedia entry says they've been introduced from British Columbia to California. I suspect they are recent arrivals along Sunset Boulevard in San Francisco because they are so noticeable that I couldn't have missed them if they'd been around last year.

The phone snaps I shot for Bug Guide weren't very detailed, so I took the FZ80 out on yesterday's bike ride, figuring I'd make a little detour to Sunset Boulevard. On the way down through Golden Gate Park, just past Spreckels Lake, an odd sight caught my eye. A woman was walking along the paved path toward the bathrooms when a dog with a chew-toy ambled past her in the opposite direction. It took a second to realize the dog was a coyote, and when it stopped to stare at me its chew-toy turned out to be a fox squirrel hanging limp in its mouth.

I scrambled for my camera and snapped a couple of grab shots while the coyote continued on its way toward the Park Stables. I followed it up the hill but didn't want to leave my bike unattended for long and quickly gave up the search. My consolation prize was a monarch butterfly that flitted past my head and took a brief rest break on a survey flag.

[UPDATE] Whatever was getting them out and about seems to have passed. I didn't see a single one on my walk yesterday (10/31). Such a great Halloween insect, too. The other update is that I finally checked iNaturalist and was surprised to see that they've been reported as far south as Escondido and El Cajon, and as far east as Riverside and Redlands. Within San Francisco they've been reported where I found them, but even more so in Golden Gate Park and the Presidio, and they have been found throughout the year, not just in fall.

The beetle has some kind of prey here, maybe a grub worm.

Here it is in its threat pose. It's said to emit a bad smell to ward off predators, and I did smell something unusual. However, given my urban location's popularity with dog-walkers, I couldn't be sure if it was coming from the beetle.