Giving my dog (Cairn Terrier) a bath the other day, I noticed a small, dark, hard, conical object at the tip of the tail. It is 1-3 mm. long. The tail of this dog has not been clipped. It could be some kind of scab. Alternatively, I wondered if it could be essentially a fingernail/claw. Is this type of mutation known?
Anecdotal evidence: my aunt once had a dog (a lab/golden cross) who habitually wagged her tail sufficiently hard on a sufficiently regular basis to deaden the tip of her tail. The tip became rather hard & leathery for a distance of 1-2 inches from the tip (but this was a gradual process over several years.) Does your dog thump its tail very forcefully when it’s happy?
Sounds like she’s developing a shih-tzu rattail. Some dogs, especially toy breeds, and especially as they get older, the skin on the tip of their tails gets very thick and keratinized and quits growing hair. It’s not keratinized like a fingernail, but more like a callous. I’m not sure whether it’s more prevalent in long-haired breeds, or if it’s just more obvious, but we see lots of shih tzus and lhasas with bald tail tips.
she doesn’t hit her tail a lot. Note that this object is very small, just a few mm. There is a discontinuity between the hard object and the normal part of her tail. She is 7 years old.