I had to come out of my usual lurking to get the advice of those much more experienced than myself-

I live in the Central Colorado mountains along the Arkansas River. I've found a great high elevation spot about 45 minutes from my house where the beavers are densely populated, and the trapping has been great this season (I've caught somewhere in the neighborhood of 20 of them since the beginning of November). But, this week, I decided I'd try my hand at trapping beavers close to my house (holiday stuff- couldn't take the time for the long drive to the "good" spot). I located an active spot in a small channel off the Arkansas River, set my traps, and I've caught three in the last three nights. However, to my chagrin, they're kinda gross (for lack of a better word). They're covered in fleas, the meat has an odd odor that makes me not really want to eat it, and, worst of all, their castor glands smell TERRIBLE. Like, just a straight up nasty urine smell.

I understand urine is part of the equation with castors, but I've been thoroughly enjoying the scent of drying castor glands in my fur shed up until now. Have any of you experienced this? They're also a dark grey color instead of the white-ish color I've grown accustomed to.

I've had that before, maybe one with a bad castor got bitten i think

I was wondering if it was some sort of infection. The first two I caught were on the smaller side and didn't have any noticeable scars. Their castors were tiny and dark (and stunk), but I didn't really think much about it since they were juveniles. The big adult I caught yesterday before I posted this had several scars and what appeared to be a fatty tumor in the skin on one of his cheeks. I kinda wonder if a call to a state biologist is in order.

What you are showing there is a common cyst that beavers will get. No biggie. The other pockets of pus they get are usually instigated by a small puncture wound of some type and bacteria form.

The smell of the castor probably has to do with their diet. Not much you can do about it.

Back in the mountain man era an expedition lead by Pete Skene Ogden ran into a population of beaver on a tributary of the Snake river (Malade river) that was eating poison hemlock roots. All the trappers that ate beaver flesh in the camp got deathly ill.

Your beaver are a very light color compared to mine in NY.
Mine are a very dark brown. Would love it if you could show the whole beaver pelt. Thanks

Only time I had funky smelling castors I was on top of a hill at a pond. No other water for a mile around and they were eating hemlock. That was some strange smelling castor but not rotten

The only time I have encountered something similar is once when I was trapping a group of beaver that were living and eating in a pine plantation, their castor just stank

I would look around and see what yours might be eating, but I wouldn’t worry about it, just don’t eat them it shouldn’t affect the furs

Dale, I agree with the usual colors our way. Up north where I am now, A buddy and I had a small mountain stream set up next to where we were hunting and caught one with quite a light color pelt on it. It was almost silver, especially the belly once dried and brushed.