The body and head structure as well as the coat of the Shih Tzu and Lhasa Apso are dramatically different, if one will only take the trouble to study the breed standards briefly.

It is broadly accepted that the Shih Tzu was originally bred from the Pekingese, Lhasa Apso and one or more Toy Spaniels (likely the Tibetan Spaniel family) in the courts of the ancient Chinese emperors up to the Chinese revolution, when the “Imperial” dogs were destroyed by the revolutionaries. However, those breedings happened hundreds of years ago and the modern breeds are completely separated and different from one another.

When I first got my Shih Tzu female from rescue I tried to find out everything I could. The main thing that stuck out from on-line searches and AKC dog shows was that this breed often loses their teeth at an early age and that an under bite is not bad. The bridge of a Lhasa is longer than a Shih Tzu- therefore the flat nose on the Shih Tzu.

Since you have 15 books on Lhasas you might think about a book on Shih Tzus or go to the American Hybrid Kennel Club’s web site and see what mixes look like. Their web site was very helpful when we received a female spaniel who had been bred with a male Lhasa/Shih Tzu mix. Seeing pictures of the puppies helped us a lot in determining things like whether or not to dock their tails.

It may be difficult to find a dog that fits your exact standards, since you don’t seem too happy with the breed standards.

see vet and u can tell but sometimes it will straighten on it’s own

You can usually get an idea when they are 3 months, but you will not no for sure until the have their adult teeth. Usually if they look okay when they are a puppy, they may still develop an underbite when they get older but it will not be too bad. If it is okay now, than they probably will not get bad enough that you can see the teeth sticking out. I grew up with a Shih Tzu and she had a severe underbite, but she had it when she was 10 weeks old so the breeder just gave her to us. I would think that since the teeth are okay now then they wouldn’t stick out of the mouth when the dog gets older.

My male French Bulldog did not have an underbite when he was 7 weeks old, but he has one now (he is almost 18 months old). Frenchies are supposed to have an underbite, so it is not a big deal as long as his teeth are even and they do not show. His don’t show and the only way that you know that he even has an underbite is to open his mouth and look at his teeth.

I am sure the reputable, dedicated breeders of Lhasa Apsos & Shih Tzus would be highly insulted to hear you say their 2 breeds were ‘inter-breeded’ (I assume you mean interbred) for years. Please, educate yourself more in this matter!

Since you are purchasing a dog sold as a mix, why are you even concerned about the bite? Obviously, this will not be a show dog.

Anyway, a dog’s lower jaw continues to grow & change longer than the upper jaw, therefore an overbite in a pup can become a scissors bite, but a pup with an underbite will always have an underbite. I learned this from a licensed Veterinary Dentist when I adpoted a Rottweiler pup with a severe overbite – that corrected just fine by the time she was 9 – 10 months old.

A shih tzu should be undershot, being overshot is a fault but not a health concern so if your not showing or breeding it shouldn’t worry you. I would like to see it undershot at 12 weeks but that does not mean it will not happen. It also does not mean it will. Is the bite level at the moment or does it have a scissor bite?

Another thing to look for is the shape of their eyes. Lhasa’s have oval eyes with a “soft” look, while Shih Tzu’s have round eyes that are very dominant.

Why are you concerned with an underbite? Unless the teeth meet incorrectly, it’s ok. A slight underbite is acceptible for Lhasa standards as long as they can close their mouth without their teeth showing all the time and their teeth overlap correctly. My Lhasa has a slight undershot bite and has since I got him as a 4 month old puppy, so I assume that you would be able to tell and it probably will not change (nothing is ever for sure, my Lhasa’s nose was black when I got him and has faded to brown over the last 3 months- which is common for brown or liver parti-colors).

If you aren’t sure about the dog being one or the other, you wouldn’t be showing them or breeding them, so an underbite shouldn’t be an issue unless it’s so severe it’s inhibiting the dog in some way and I’m sure there would be signs of it now.

Have you seen the parents of this pup … what do their bites look like?

While the Apso standard calls for a level or slightly undershot bite, the teeth should not show or protrude. Since you’re not buying a dog that’s been bred to standard, you take your chances.