What specific rodent is this? - Ask Extension
This critter has a long skinny tail (not bushy), is larger than a mouse (about 5” body), has long whiskers, is nocturnal, and is very smart. What is...
Knowledgebase
What specific rodent is this? #811858
Asked September 22, 2022, 4:58 PM EDT
This critter has a long skinny tail (not bushy), is larger than a mouse (about 5” body), has long whiskers, is nocturnal, and is very smart. What is it?
Deschutes County Oregon
Expert Response
Hello Brie,
Thank you for reaching out to OSU Extension Service. While the photo isn't of the full body of the mystery rodent, based on what I can see and from your description, and your location of Deschutes County, there are several possibilities: a Northern Grasshopper Mouse, a Piñon (Pinyon) Mouse, or a Deer Mouse, all three of which occur in Deschutes County. Here's a link to the Oregon Department of Fish and Wildlife's page on mice and rats: https://myodfw.com/wildlife-viewing/species/rats-and-mice.
You mentioned it being nocturnal, however, mice in general are nocturnal. All three of the mice species I listed also have fur coloration pretty closely to what I can see in the photo, so that alone isn't enough to positively ID the critter.
What I can't see is the tail, but you described it as long. For description of tails for each, here's what I found (source: https://animaldiversity.org/ - Univ. of Michigan Museum of Zoology):
Ultimately, the actual identity of your mouse likely comes down to the tail length and features, and possibly ear size.
The list of species above also has a link to the source I used to describe each. Take a look at each and hopefully, you'll have a pretty confident idea what species you have. Be sure to look at the kinds of habitat they prefer, too, as this is another good way to narrow down your possibilities.
I hope this information helps! Thank you again for contacting OSU Extension Service.
Thank you for reaching out to OSU Extension Service. While the photo isn't of the full body of the mystery rodent, based on what I can see and from your description, and your location of Deschutes County, there are several possibilities: a Northern Grasshopper Mouse, a Piñon (Pinyon) Mouse, or a Deer Mouse, all three of which occur in Deschutes County. Here's a link to the Oregon Department of Fish and Wildlife's page on mice and rats: https://myodfw.com/wildlife-viewing/species/rats-and-mice.
You mentioned it being nocturnal, however, mice in general are nocturnal. All three of the mice species I listed also have fur coloration pretty closely to what I can see in the photo, so that alone isn't enough to positively ID the critter.
What I can't see is the tail, but you described it as long. For description of tails for each, here's what I found (source: https://animaldiversity.org/ - Univ. of Michigan Museum of Zoology):
- Northern Grasshopper Mouse - it is described as thick with a white tip, not more than 30% (~1.5 inches) of its body length (see below) - this leads me to believe it's not this species based on your description;
- Piñon Mouse - it's tail is longer, (3-nearly 5 inches), tipped with long hairs and has a dark dorsal (top) stripe running down its length. It appears to have a distinctly white belly and feet, but so do both the Deer Mouse and the Northern Grasshopper Mouse.
- Deer Mouse - It's tail ranges from 1.75 - 4 inches, not as long as the Piñon, but can be quite long. If you have other photos or recall from your observations, several other physical characteristics of the Piñon Mouse are a tufted tip on the tail for the having a white-tipped tail.
- Piñon Mouse - ranges from 6.75 - 9 inches), so within the possibility if your mouse is on the smaller size (and fully grown).
- Deer Mouse - ranges from ~4.5 - 8.75 inches, so well within the range of your mouse.
Ultimately, the actual identity of your mouse likely comes down to the tail length and features, and possibly ear size.
The list of species above also has a link to the source I used to describe each. Take a look at each and hopefully, you'll have a pretty confident idea what species you have. Be sure to look at the kinds of habitat they prefer, too, as this is another good way to narrow down your possibilities.
I hope this information helps! Thank you again for contacting OSU Extension Service.
Hi
Thank you for this valuable info!
I am truly sorry about this image of its offspring. Unfortunately I had them chewing up the material around my truck battery (in the garage), storing caches of pine nuts in the garage, and chewing up other materials (they had to climb up a metal garage rack to the ceiling to get the material).
This is its baby: Is it a Deer Mouse? Belly and under tail is white. Very large eyes, rounded ears, long whiskers, long skinny tail.
This was very difficult for me to do, as I love wildlife. However, I can’t afford them chewing wires in my truck etc.
Hi
Thank you for this valuable info!
I am truly sorry about this image of its offspring. Unfortunately I had them chewing up the material around my truck battery (in the garage), storing caches of pine nuts in the garage, and chewing up other materials (they had to climb up a metal garage rack to the ceiling to get the material).
This is its baby: Is it a Deer Mouse? Belly and under tail is white. Very large eyes, rounded ears, long whiskers, long skinny tail.
This was very difficult for me to do, as I love wildlife. However, I can’t afford them chewing wires in my truck etc.
Hi Brie,
Thank you for the additional photos. I completely understand the dilemma you faced in this situation. Sometimes, we are forced to resort to lethal measures when the wildlife we love and appreciate crosses a line and becomes a nuisance to us, including causing damage to our property, sometimes to costly ends. Chewing on wiring falls into that category and trapping is a viable option.
The reason you're seeing mice in your garage this time of year is that they are in the midst of their seasonal Fall flurry to cache food and find a winter nesting site. Sometimes, these sites are our vehicles. From a mouse's perspective, they are ideal homes! Imagine having perfect nooks and crannies to establish a nest, plenty of fluffy, easily chewable insulation and plastic (for bedding, but also mice chew because they need to keep their teeth sharp and filed down - rodent teeth don't stop growing like our teeth), and heating from a warm engine block.
For a number of weeks through the Fall and periodically throughout the Winter, I recommend inspecting your vehicle for mouse activity and continuing to set traps - snap traps baited with a mixture of peanut butter and rolled oats are effective. This will keep new damage from getting out of hand.
Another step you will want to do is inspect your garage for easy access points (loose siding, vents, eaves, windows, overhead door and door jambs, etc.) about the diameter of a dime or larger (large enough for the mouse head to fit through). If mice are able to get into our structures, trapping will not be enough to keep their numbers in check. If your garage isn't falling into significant disrepair or because it's an old out building (making entry impossible to prevent), you should be able to make most repairs inexpensively (using steel wool packed into crevices and sealed with expandable spray foam, tightening up the fit of doors and windows around the sides and bottom - sometimes that is as easy as replacing weather stripping). In the end, sometimes even after our best efforts to exclude critters from places like garages, entry is possible - we are in and out of these places often and mice can scurry in when we open the doors.
As for identity, I can't say with complete certainty, but what I can see is a very dark upper side on the tail, which would describe the Piñon Mouse, but I can't tell in photos if there's a tufted tip on the tail, also diagnostic of the Piñon Mouse. In my first response, I messed up the information when describing the Deer Mouse. What I meant to make sure it said was that the Piñon Mouse tail is tipped with long hairs and has a dark dorsal stripe running down its length, where as the Northern Grasshopper Mouse has a white tipped tail (although this is not a Northern Grasshopper Mouse) and that the Deer Mouse isn't described this way. Both the Piñon and Deer Mice have large eyes and long whiskers.
It definitely could be a Deer Mouse, because they do make these annual movements into our homes and buildings, and the coloration and size of your mouse look about the same as that species (except the tail has dark dorsal fur). I'm uncertain if Piñon Mice are also prone to enter our spaces.
I hope this added information is helpful. Thank you again for contacting OSU Extension Service. Best of luck as you handle your nocturnal visitors!
Jason
Thank you for the additional photos. I completely understand the dilemma you faced in this situation. Sometimes, we are forced to resort to lethal measures when the wildlife we love and appreciate crosses a line and becomes a nuisance to us, including causing damage to our property, sometimes to costly ends. Chewing on wiring falls into that category and trapping is a viable option.
The reason you're seeing mice in your garage this time of year is that they are in the midst of their seasonal Fall flurry to cache food and find a winter nesting site. Sometimes, these sites are our vehicles. From a mouse's perspective, they are ideal homes! Imagine having perfect nooks and crannies to establish a nest, plenty of fluffy, easily chewable insulation and plastic (for bedding, but also mice chew because they need to keep their teeth sharp and filed down - rodent teeth don't stop growing like our teeth), and heating from a warm engine block.
For a number of weeks through the Fall and periodically throughout the Winter, I recommend inspecting your vehicle for mouse activity and continuing to set traps - snap traps baited with a mixture of peanut butter and rolled oats are effective. This will keep new damage from getting out of hand.
Another step you will want to do is inspect your garage for easy access points (loose siding, vents, eaves, windows, overhead door and door jambs, etc.) about the diameter of a dime or larger (large enough for the mouse head to fit through). If mice are able to get into our structures, trapping will not be enough to keep their numbers in check. If your garage isn't falling into significant disrepair or because it's an old out building (making entry impossible to prevent), you should be able to make most repairs inexpensively (using steel wool packed into crevices and sealed with expandable spray foam, tightening up the fit of doors and windows around the sides and bottom - sometimes that is as easy as replacing weather stripping). In the end, sometimes even after our best efforts to exclude critters from places like garages, entry is possible - we are in and out of these places often and mice can scurry in when we open the doors.
As for identity, I can't say with complete certainty, but what I can see is a very dark upper side on the tail, which would describe the Piñon Mouse, but I can't tell in photos if there's a tufted tip on the tail, also diagnostic of the Piñon Mouse. In my first response, I messed up the information when describing the Deer Mouse. What I meant to make sure it said was that the Piñon Mouse tail is tipped with long hairs and has a dark dorsal stripe running down its length, where as the Northern Grasshopper Mouse has a white tipped tail (although this is not a Northern Grasshopper Mouse) and that the Deer Mouse isn't described this way. Both the Piñon and Deer Mice have large eyes and long whiskers.
It definitely could be a Deer Mouse, because they do make these annual movements into our homes and buildings, and the coloration and size of your mouse look about the same as that species (except the tail has dark dorsal fur). I'm uncertain if Piñon Mice are also prone to enter our spaces.
I hope this added information is helpful. Thank you again for contacting OSU Extension Service. Best of luck as you handle your nocturnal visitors!
Jason
Thank you for the added information re sealing up my garage. The large garage door needs something better on the bottom corners.
This mouse does not have tufted fur at the end of its tail. So I think it’s a Deer Mouse.
PS Do these mice ever cross breed with different species of mice? I believe that the adult came in on a load of firewood from Sunriver. I never saw 2 adults, but the babies suggest there’s another one.
I did have “regular” mice in my backyard (tunneling under the earth).
You’ve been very helpful and wonderful!
Thank you!
Hi Brie,
Thank you for the follow-up. To my knowledge, the deer mouse doesn't hybridize with other species. I could be wrong, but I don't think they do.
Regarding the tunneling mice, you may have voles. Voles are mouse-like rodents that make shallow tunnels in grassy meadows and lawns, and sometimes this can be damaging, especially to lawns that many people want to keep well manicured. They are also fond of young saplings and shrubs (they will chew around the base for the tasty cambium layer of the bark), which can end up killing them if they chew completely around the base. In the winter, voles will tunnel under the snow, clipping down grasses to form little runways. When the snow melts, these runways are visible until the vegetation grows back. Voles go through "boom and bust" cycles in their population, so one year you may see lots of signs of voles and another year, you won't see anything.
Here's a great presentation by our Extension Wildlife Specialist, Dana Sanchez, on various rodents that can be concerning to homeowners: https://extension.oregonstate.edu/video/dueling-diggers-gophers-moles-voles-ground-squirrels. Dana also has a terrific website with lots of other materials regarding wildlife: https://extension.oregonstate.edu/people/dana-sanchez.
Thank you again for your email and reaching out to OSU Extension Service!
Thank you for the follow-up. To my knowledge, the deer mouse doesn't hybridize with other species. I could be wrong, but I don't think they do.
Regarding the tunneling mice, you may have voles. Voles are mouse-like rodents that make shallow tunnels in grassy meadows and lawns, and sometimes this can be damaging, especially to lawns that many people want to keep well manicured. They are also fond of young saplings and shrubs (they will chew around the base for the tasty cambium layer of the bark), which can end up killing them if they chew completely around the base. In the winter, voles will tunnel under the snow, clipping down grasses to form little runways. When the snow melts, these runways are visible until the vegetation grows back. Voles go through "boom and bust" cycles in their population, so one year you may see lots of signs of voles and another year, you won't see anything.
Here's a great presentation by our Extension Wildlife Specialist, Dana Sanchez, on various rodents that can be concerning to homeowners: https://extension.oregonstate.edu/video/dueling-diggers-gophers-moles-voles-ground-squirrels. Dana also has a terrific website with lots of other materials regarding wildlife: https://extension.oregonstate.edu/people/dana-sanchez.
Thank you again for your email and reaching out to OSU Extension Service!
