We suspect the varmint that left the teeth marks on the Butternut Squash the other day was probably either a California Ground Squirrel (Spermophilus beecheyi) or some sort of canyon rat. If it had been a raccoon or a possum, the whole squash would probably have been gone. If it had been birds, there would have been signs of pecking, but these were pretty healthy chomps by teeth.
There are several types of rats that hang out in the canyon behind us; we know for sure that there are members of the Neotoma species, also known as Wood Rats, Pack Rats or Trade Rats, but we've just been calling them Pack Rats. We know they're here because we've found two middens in the area. One midden is on the other side of the driveway wall; the second was destroyed when Greg cleared the brush out from behind the fence.
Pack rats construct their middens out of whatever material is available, including sticks, twigs, leaves, rocks or whatever. I left a paintbrush on the driveway wall several years ago and found later that it had been incorporated into the wall of the Pack Rat midden a few feet away.
About a year ago Cindy left the lid of the compost bin ajar. When she went to add something to the compost heap, she discovered a Pack Rat staring back up at her; it had evidently climbed or fallen in trying to get at the vegetation in the bin and couldn't get out. We started calling it "Mickey" on account of its huge round ears. Anyway, we opened the bottom door of the bin and left the area, and Mickey evidently took to his heels because he was nowhere to be seen when we came back.
According to the San Diego Natural History Museum, Pack Rats don't need to drink water, but "require quantities of succulent vegetation ... for moisture". Yup, "succulent vegetation" describes our beautiful Butternut Squash, so Mickey and his cousins are suspects along with the Ground Squirrels.
Once the anti-varmint panels are finished, they'll all have to go somewhere else for their "succulent vegetation." Maybe they could try eating some of the humongous jade plants out in the canyon.