Norway Rats vs. Roof Rats

Pest rats in California come in two varieties - Roof and Norway. Around my house, they are 'dead' and 'deader'

I was recently skimming through some of my old kill't rat photos when something that had been in the back of my mind for a while finally took shape.

After spending more time looking at the photos and doing a bit of web research, I now think that the rats I had been identifying as 'adult' Roof rats (Rattus rattus) are actually Norway rats (Rattus norvegicus). Have a look at the following side-by-sides and see if you agree that these are two different species: the first is the one I now believe is a Norway, the second I still think is a Roof. The most commonly-referenced distinguishing characteristic is the tail. The tail of the Roof rat is longer than the body and head combined, while the Norway rat's tail is shorter than the body plus head.

Norway Rat?

Note the long body and lighter color. The tail seems on the long-side for a Norway, but is likely just short of the length of the body+head


In the mug shot, you can see the smaller, "Norwegian" ear-to-head ratio

Roof rat?

Smaller overall, longer tail than head+body, more grayish color


The ear (what's left of it) is larger in proportion to the head

I had always thought it strange that the coloring was so much lighter and browner on the big'uns, but just chalked it up to variation. Plus, I had read somewhere a while ago that Norways and Roof rats tended not to be found sharing the same territory (see quote below). And since I knew I definitely had Roof rats -- they are very agile climbers and have been seen (and shot) in my tree -- I assumed that they were the only ones I had.

Basically, I did a lot of assuming -- and I know what happens when I assume.

Have a look at the details/specs on the following site (Anne's Rat Page). Heck, while you're there, take the quiz:

http://www.ratbehavior.org/QuizNorwayRatRoofRat.htm

As mentioned, Roof rats (a.k.a., black rats, ship rats) are excellent climbers, often living in nests above ground. Norway rats (a.k.a., brown rats, sewer rats) more often tend to be burrowers. Regarding overlapping populations, I found this quote on the Internet (source is unclear):

"The present distribution of the Norway and roof rats appears related to two factors, competition between the two species and the reaction of both to different climates. When the aggressive Norway rat and the roof rat compete for the same areas, the Norway rat frequently becomes dominant, and the roof rat soon disappears. Only under special conditions do both species live in the same area. In one eastern seaport, roof rats live in the top of grain elevators and Norway rats live in the bottom. This is probably because roof rats are better climbers than Norways. It is generally only in such situations as these that roof rats are found living in Norway rat territory."
-- http://www.angelfire.com/tx/mariorios/norway.html

So based on my new assumptions, I now see my backyard as a melting pot of rodentia, where rats of all races and creeds come to live. It's my job to welcome each and every one of them with a .20 caliber handshake.

Tales from the Way Back Machine

Close your eyes. Clear your mind. Allow me to take you back to the Summer of 2006...


(Cue "The Time of the Season" by The Zombies, slo-mo footage of chopper blades over a Vietnamese jungle, and -- wait. It was '06, not '66. Never mind.)

It was the first Summer with my Gamo Hunter 440 in .177 caliber, which I had already used to dispatch a handful of rats that were brave (and foolish) enough to come out during the day. I had a 4x fixed power scope on the rifle at that point, with a 32mm objective lens. It wasn't great in low light situations, but it worked well in the day for shooting at my range (17-22 yards). So after many target sessions, and the occasional pest control shooting, I had grown very confident with the gun. I felt that what I put the crosshair on, I was going to hit.


The original rat thumper

As mentioned, my shooting had always been confined to daylight hours. But there was activity going on at the feeders even after the lights when out. I found that out one night when I went out back to watch for the space shuttle re-entry with my binoculars. As I stood out in the middle of my lawn, I heard some scuttling at the feeders which were about 20 feet away. Since my eyes were adjusted to the dark, I was able to put the field glasses on the feeder and see a couple of rats pilfering seeds right from the source. Up to that point I had naively assumed that the rats were confining themselves to what food dropped to the ground. But these were roof rats -- exceptional climbers -- and making their way through the tree to the feeders was no problem at all.

So more than a little ticked off, I camped out the next night with a flashlight trained on the feeder. Even with the illumination, it was a dim sight picture through that small scope. But I could see enough.

At right about 9 o'clock I was jolted out of my quiet surveillance by the sight of a dark brown shape in the branches of the tree. Those little bastards had come back for more free dinner. They seemed wary of (but not deterred by) the light. The first rat ventured down onto the feeder, but kept himself behind it with the feeder shielding him from the light (and my gun). Occasionally, he would peer around from behind the feeder on the right side with just about 3/4 of his head appearing in the light -- clearly he was curious about what this spotlight business was. The next time he did this, I put the scope on what I could see of his head, snicked off the safety and took the shot. I heard the pellet go into the vegetation at the back of the yard, and I couldn't see the rat any longer. As tricky as the shot was, I still had strong a feeling that I'd gotten him.

I didn't want to spook the second rat, so I stayed put, hoping he'd come back. As quietly as I could, I loaded up another .177 Crow Magnum pellet and continued the stakeout.


The always reliable Crow Magnum hollow point pellet

Within ten minutes, I caught a glimpse of some shadowy movement above the feeder. I then watched rat #2 dip down and grab some seeds -- this time from the front of the feeder. In fact, he balanced himself directly on one of the perches that the birds use, giving me a perfect profile. But I was leery of taking the shot for fear of the pellet over penetrating and damaging the feeder. So I kept watching him as he took the seeds and moved back up to a branch about a foot above the feeder, where the illumination from the flashlight was much less bright. From what I could dimly make out, he seemed to be happily eating his loot up there. So again, I lined him up as best I could, pushed off the safety and squeezed the trigger. Another sound of the pellet passing through leaves and branches, and no sign of the little bugger.

I was certain I had missed this time. After another ten minute vigil, I realized he'd been spooked and wasn't coming back this night. So I went out to retrieve the one I felt sure I'd hit. Much to my surprise, there were the lifeless bodies of both rats laying in the grass directly under the spots they'd dropped from.

Surveying the carcass of the one I shot off the feeder I saw that I had indeed put the pellet right in his crankcase (really that was all I could have hit without somehow passing through the feeder). The force of the pellet into his melon had somehow knocked a perfect half of his brain out of his skull, and it lay neatly some few inches away from his body. It was really bizarre and a bit unsettling. I wish I had gotten pics to document it, but at the time, it didn't even occur to me.

I have always been particularly proud of that shot -- nighttime, sliver of a target, and using that 4x scope. I put that pellet exactly in the one spot I could have to hit the target and miss the feeder, and he was dead before he hit the ground.

The second rat had gone down without a twitch due to a well-placed heart/lung shot. I disposed of both rats and packed it in for the night.


The scene of the night's action, shot during the day

After that night, I curtailed my elevated shooting because I realized that my backdrop was questionable at that height with a neighbor directly behind me. The sound of those pellets going through the rats and into the vegetation was enough to convince me of that. It was at that point that I started occasionally baiting on the ground to try to lure targets back down to safer shooting. But that's a future "Tale from the Way Back Machine". Excelsior!