Started a new line, of 17 rats caught so far 8 have been badly bitten up damaged. See one of the worst examples pictured. Of the previous 100+ I've put up this fall I had maybe 3 or 4 with some bites. These sets only had 10hrs between checks. Why is this happening? Is this other rats biting the dead ones in the trap or something else?

What is the density of rats where you are getting these. If there are a lot of rats they will fight and bite. a trapper near me trapped a short section of a ditch and caught 50 rats in about a quarter of a mile. When he started fleshing he noticed about one out of three were so bitten up that holes were common. Your wounds don't look all that fresh but if you are setting den openings and or n colonies you could get more rats biting the dead ones.

Bryce

Actually,that dont look that bad.i seen rats in spring bit up way worse than that.

Density hard to say. Appears to be plenty of rats here but its public land and a fairly easy walk. I'm sure it was previously trapped near opening.

Sets were almost exclusively body grips at den entrances. One was a leg hold set at a toilet though that was bit up.

Any flooding and do you have blue herons?

Toilets are territorial so those can get bit up sometimes.

Neither is an issue. Most of these caught under ~1" ice.

dont know about the throat, but the rest of those bites look to be dead bites, or post mortem. no bruising/blood or scars.

also, a dead rat stuck in a den entrance will get bit and dragged out of the way by the next rat coming through. appears to be the case here.

For sure post mortem for reasons you specified. Also moisture between the fur and meat when skinning.

Thanks for the comments. Hopefully just a run of bad luck here.

if the water levels are right, maybe move the coni back away from the entrance so its not plugged with the dead rat. hopefully just a run of bad luck, like you said, and things straighten out for you.

Drink less Hamms!

Moosetrot

Ha!

I had this happen a few years back with beaver. It was a very dry fall. I think that some beaver were forced to relocate as their habitat dried up. This created territory conflicts I'm guessing.

Has it been a dry season around there?

Hmmm maybe something like rat displacement could be playing a role. The areas I'm trapping has water controls (so no fluctuation) but the other side of the dike is at the mercy of the river, which was high for long period of time but is now finally receding some. Getting a fair amount of rats on the checks here but nothing too crazy. Thanks.