Rat hole?

Asked May 26, 2017, 7:45 PM EDT

I have these holes in my back yard, in non-lawn areas. It is a large yard, with a slow moving creek, but without debris or trash. Backs up to a wooded area. I've seen rabbits and evidence of moles but no rats. The holes are about 3 inches in diameter. Any ideas? Thanks. John

Washington County Oregon vertebrate pest management pest identification

5 Responses

Burrows can pose a good puzzle. These could be rat (Rattus) holes, however there might be additional suspects. The size is within bounds for ground squirrels, but ground squirrels are out and about in daylight and I imagine you'd have seen ample evidence of them if that's who was doing this.
Are there lots of holes/tunnels? If your area has ferns, have you noticed cuttings anywhere associated with these holes? Mountain beaver (Aplodontia rufa) likely wouldn't burrow in the wetted area so much as the immediate upland, especially the wooded parts.
If the holes are in the wetted area nutria could be a suspect, but these are fairly small for the holes I'd expect a nutria to rip out.
Happy to follow up with you on this,

Hello Dana -

Thanks very much for your thoughtful reply.

First, we have not seen any ground squirrels on our property. Yes, there are lots of tunnels and scattered holes. We do have ferns but have not noted cuttings around them. I have caught two moles in the area in typical mole tunnels. But, do moles make holes like these?

I have seen nutria in the wild and agree that they are probably too large for these holes.

We do have a few rabbits around but they would appear to be too large for the holes also. Do they tunnel?

Thank you again for your help. I have another problem - something is digging under the chain link fence. Pretty big holes - 1 -2 feet across and maybe 10 inches deep. Raccon? Coyote? I could send you a picture if it would be of interest to you.

The interesting thing is that, after living here for 20 years, this is the first time we have had such issues (and problems with deer). It all started when our golden retriever died. I guess his presence helped to keep things away. You sure have a good looking dog.

Thanks again.


Thank you for the additional information. I don't think the holes indicate moles, and eliminating the other potential suspects as you've helped to do here leads me to think the holes might be from mountain beavers, or "boomers."
The hole under the fence could be created by one animal and enlarged by others. I think coyotes, foxes, raccoons, and possums (along with skunks) would all consider that a passable gap by which to enter your yard, and might be contributing to its enlargement. I would create an above-and-belowground barrier there by sinking some hardware cloth down at least a foot or 18" and then if you're able to, extend it in an "L" so the apron faces out. Doing so creates an discouraging "un-diggable" barrier back a little ways from the edge/fence itself, and can help encourage an animal to move along (or try elsewhere.) Once begun, a fence under-dig can become an established route, so you're right to be considering remediation now. Yes, your dog's presence likely did discourage a lot of potential wild visitors. I'm sorry for your loss and hope you'll soon be able to adopt a new companion. And thank you - Strega is a Nova Scotia Duck Tolling Retriever :)

Thanks again Dana. Sorry to be a bother by repeatedly contacting you. I investigated the mountain beaver on the internet and found a very good article from the state of Washington on the subject. From what I read, that is likely what we are dealing with but I have yet to see one. The tunnels and holes, however, continue. I am still concerned about rats, but don't think they would be so much out back by the snail (which has some water year around). The swail was put in by Washington County as a "water treatment" device (and there is an easement allowing this to occur). Maybe someone from WA County would come out to look at the situation, although I rather doubt it. Meanwhile, any ideas on how to rid our property of this animal?

Interesting about your dog Strega. We have had goldens over the years and been slow to replace our last one MAx. But, we learned about the Tolling retrievers and even went to the Portland dog show to take a look at them. To our view, they look much like a smaller version of the golden. But, in discussion with others, we got the impression that they are maybe more "hyper" and might not be the dog for us for that reason. While retired, we are pretty young, mid-60's and active. But we are probably looking for something smaller than a 80 pound GR, like our last was, even though he was not fat. Any thoughts?

I have taken up too much of your time but appreciate your advice and think that the OSU Extension service is excellent. Never used it before - read about it in the Oregonian.

Thanks again,

John Lemmer

Your District Biologist from OR Dept of Fish and Wildlife (try Don VandeBergh at 503-621-3488 or call Salem HQ at Main Phone (503) 947-6000 or (800) 720-ODFW [6339]) could potentially help get eyes-on ID of the holes. Here's a link to an old publication on management of boomers that might be useful for its info on trapping techniques and timing http://icwdm.org/handbook/rodents/ro_b53.pdf
Tollers are very bright and high-energy companions that thrive on having "a job." That "job" however could be any of the many, many fun dog-sports that people play with their dogs, from agility to barn hunt to nosework etc - They are definitely NOT limited to being hunting retrievers, although in most the drive to 1)retrieve and 2) please you are quite strong. I'm a convert and cannot imagine not having one now :) As with any dog, it's always important to meet the breeder, find out how the parents scored on health tests, meet the parents if possible-especially the mom's temperament, and find out how the puppies are being socialized before committing your heart to a puppy. There's also a rescue network that places (fortunately fairly rare) dogs plucked from situations of need but you can learn lots here www.nsdtrc-usa.org