Rats can be a big expensive problem with newer cars using soy-based wiring insulation; see Rats! New Cars' Soy-Coated Wires Give Rodents Plenty To Chew On.
Update: according to Bob B:
Hi, that's a Pika, a close relative of the rabbit, it's not a rodent. They live at high elevations, would be good if you can get it back up high somewhere. They are very cute and hard to find for most of us. I doubt it will hurt your van.
I think not—pikas do not have the long rat tail that this creature did. I have seen pikas a lot, but usually at 10,500' on up; this one was at 10,000'. I am now sure this was no pika, given the tail.
It did do some damage to the van (gnawed on insulation, started stuffing vegetation in). And maybe more that I could not / cannot see.
According to Dick N:
A woodrat by any other name is a woodrat. Neotoma fuscipes - Dusky-footed Woodrat.
and Mark C:
It’s not a pika, at least the image doesn’t look like one. Ears look too big, for one thing. If it has a visible tail, it ain’t a pika. https://faculty.ucr.edu/~chappell/INW/mammals/pika.shtml
Also, pikas are diurnal and woodrats (packrats, Neotoma, whatever) are very nocturnal. Reaching back even farther into the decades, I spent a summer at the Hall Natural Area, working on small mammals. That was about 10K feet, and we occasionally caught woodrats if we left the livetraps open at night.
Its relatively hairless and quite long tail persuade me that it was a dusky footed woodrat—an animal with a long hairless tail would be losing body heat at 0°F mountain winters, and the tail would frostbite quickly. And it came on board within ~2 miles of the Hall Natural Area.
Below, as originally written before learning it is Neotoma fuscipes
This mouse below (well OK it’s a pack rat and a darn cute one) has set up shop in my engine compartment last night and does not want to leave. It was 23°F up at 10,000' and a nice cozy Mercedes Sprinter engine compartment must feel really good.
I stayed up near Saddlebag Lake the night of Oct 14. In the wee hours, I heard scurrying noises around 1 AM. I started the engine to scare off whatever was messing around in my engine compartment. It did not work; the scurrying restarting not long after, but I fell asleep.
Waking up at first light before sunrise, I spent 20 minutes trying to shoo out cute little Mickey Mouse that had set up shop in my engine compartment. We studied each other for 10 minutes, and from what I could tell, s/he wanted to be friends, so much so that s/he did not want to leave even with the engine running. Just looking wide eyed at me two feet away.
On the practical side, MM is not a good guest. So far, only minor chewing damage, and I examined every hose and belt I could see, using a flashlight.
The problem is, I cannot get MM to leave, even in the daytime. S/he seems happy as a clam after having taken a ride down 3000' to near Lee Vining. I had thought s/he was out/gone out looking for a more plush Sprinter van, or maybe... a Bentley or something.
I kind of don’t want to spend my winter starving to death down some dirt road when MM chews through the wrong hose or wire, so I’ve parked and propped open the engine compartment. Maybe that will persuade MM to go, particularly around noon when the sun can shine into it. But if MM just hides in some shaded nook or cranny (plenty), I’m going to need some other solution. She is already a poor house guest and cannot be allowed to take up residence and just chew up everything s/he pleases, even if radiator hoses and wiring sheaths are tasty—cars can be totalled that way and then MM would not have a nice warm place to stay.
But I don’t want to be friends, not in my Sprinter van, so I tried leaning on the horn for 20 seconds, opening up hood so sun shines in, idling the engine. Some friendships just don’t work out.
I can’t go on a hike or anything until I am sure that MM is housebroken or out. Chewing up inulation is one thing, but I like my radiator hose just the way it is. The vegetation brought in to make things more comfy had to go too.
Update: I think MM might have left (though I thought that hours ago also). So now I have to drive to quiet place and listen for faint scratching noises. If s/he still wants a friend, I’ll see about that state trooper across the highway!
Update 2: I was wrong. Seems like MM just had her feelings hurt and is playing hard to get.
Update 3: some new lucky friend perhaps... no more signs of MM the next day... parking in the sun and idling the engine (which didn’t bother her before) and leaning on the horn might have done it. I had a bit of a scare when I thought that MM had set up shop inside the air intake filter box, but everything seems to be working now. Hopefully not a deceased MM inside there. Nose will tell in 3-4 days if nothing else.
That’s the air intake filter below and boy am I glad MM didn’t start chewing through the filter and entering the passenger compartment ventilation system. That tape is because I put an extra activated charcoal filter over the stock one, for better filtration of odors—it helps, especially with MM not being housebroken and all.
Jim: Time for you to pack it in? Give him a name, Mickey Mouse would be fun, and put it on Twitter!!!
Lloyd: I’m driving to your place right now... park right by your garage...
Jim: Then, follow ups : the Adventures of MM, etc"!
Lloyd: ...and he scurried away forever.
Jim: And how poor little MM discovered fancy SF suburbs!😂
Lloyd: this cute little mouse is a foot long (with tail). Might be gone now, gonna have to drive to a quiet place and listen.
Jim: Oh be nice. Poor little mouse! Don't say rat. It's bad for Public relations. The photo is cute. Maybe God sent him to make you famous! Work it kid!!!
Lloyd: it is a big rat. very cute though.
Jim:Sample headline: Mouse moves into car with me in the wilderness to get out of the cold!
Jim: Should I adopt cute little Mickey?
Lloyd: yeah, right in your Bentley back seat!
Jim: Mickey has asked me to adopt him. He even declined to move into a Bentley!😆
Doesn't anyone want to adopt Cute little Freezing Mickey??
Lloyd: Maybe that state trooper across the highway...
Lloyd: seriously... I have my hood up and he’s writing a ticket. I’m curious if he will come over and check on me or if “to protect and to serve” means ignoring potentially stranded motorists.
Mark C writes:
Many decades ago I had a VW destroy its engine because a pack rat build its nest in the airflow ductwork around the engine (which was air-cooled, at least pre-nest). And when I worked at the Barcroft Lab there were occasional problems with marmots snacking on tasty grease-covered brake lines.
More to the point, I’m not sure if Neotoma carry Hantavirus — lots of rodents besides Peromyscus (deer mice) can although it’s not clear they transmit it to us. But at least in some areas, Neotoma carry another nasty virus, Whitewater Arroyo Virus (frequently fatal). You definitely don’t want a pack rat living in your vehicle’s ventilation system.
If you can heat-soak the car for long enough in hot sun, that ought to discourage your guest, but a big vehicle has a lot of thermal inertia so it may be difficult.
It’s not a pika, at least the image doesn’t look like one. Ears look too big, for one thing. If it has a visible tail, it ain’t a pika.
DIGLLOYD: I did the heat soak thing yesterday, and I think that did the trick. Fortunately it never got into the ventilation system, just around the perimeter.
Jason W writes:
Mark C's saying that White Water Arroyo virus is "frequently fatal" seems to understate it. In the most salient case where 3 patients were infected 100% died within 8 weeks. This definitely makes a strong case for water filtration!
DIGLLOYD: yikes. Not sure what Jason means about water filtration, but the MSR Guardian water purifier is my recommendation, and a wide move for disaster preparedness.
Mark C continues:
I concur that water filtration may not be relevant; from what little is known about WAV, the route of infection seems similar to Hantavirus: through urine, feces (most commonly dried to dust and inhaled) or maybe biting (not sure if there have been cases of transmission to humans by bites, but that appears to be how deer mice often infect each other). Yes, the few well-documented cases of WAV have usually (always?) been fatal. But it’s not clear (to me) if there are more-or-less symptomless infections, as with Hantavirus. For example, a friend of mine, a mammalogist, tested positive for Hantavirus antibodies — indicating exposure at some point — but she cannot recall ever feeling any of the standard symptoms. There are reports of other similar cases among mammalogists. As a counterpoint: I worked with thousands of deer mice, many wild-caught, in the lab in the ‘80s, and am not seropositive (suggesting but not proving no exposure). This despite doing all the wrong things in those days of innocence before Hantavirus was discovered: being bitten, peed on, breathing dust when cleaning cages, etc. (Now I’ve wandered WAY off topic…).
Whether or not there are non-pathogenic infections with WAV, the best policy is, obviously, Don’t mess with it. I would treat any woodrat urine/feces as potentially infectious. The standard Hantavirus protocol is to spray deer mouse ‘leavings' with 10% bleach before cleaning. That’s probably a good idea for woodrat stuff as well.
And of course, any wild rodent in the western US could carry bubonic plague. Or any wild mammal — there’s a famous case some years back of an NPS employee at Grand Canyon who did a necropsy on a dead mountain lion, caught plague from the carcass, failed to recognize the symptoms in time, and died.
David C writes:
That reminds me of a story that turned out quite differently. Guess how it turns out for a woodchuck in the fan cage of an 8v71 diesel compressor engine when you start it up unawares?
DIGLLOYD: how much wood could a woodchuck chuck if a woodchuck could chuck wood?