In another forum, an user claimed that squirrels' teeth grow again if they are somehow lost. So, if you would pull out a tooth (please don't do this!), it would grow back again. Is this true? If yes, how long would it take to grow back?
There are over 200 species of squirrels broken down into three categories: tree squirrels, ground squirrels, flying squirrels. Since the most common variety is the tree squirrel, that's what I'm discussing here. It's also the kind from the source in Charlie Brumbaugh's answer, Squirrel Refuge.
I had lengthy discussions with Wildlife Rehabilitators at Cummings Veterinary Medical Center of Tufts University, Wildlife Clinic, Squirrelmender Wildlife Rehabilitation, Squirrel Lover's Club, and did some online research.
From what I learned, the answer to your question is, in almost all cases, no. If a tooth has been completely removed, including the root system, no new tooth will grow in its place. As with other animals, and even people, the heart of the tooth is its root system.
A squirrel's two top and two bottom incisor teeth (the pointy ones) never stop growing. The average is up to 6 inches per year. Teeth are needed to break nuts and eat other things, and as they eat, the teeth can grind down. Constant growth keeps the squirrels alive. They can't eat without all of their incisors intact, pointed, of the proper length and functioning together in perfect alignment. Under any other conditions, the squirrel will die of malnutrition. The most common conditions I'm referring to are malocclusion, cleft palate, or a broken jaw.
In rare instances, teeth that have been broken off can continue to grow. If it has a full healthy root system, and no other mitigating factors, there are times when growth will continue. Unfortunately, without treatment, the broken tooth doesn't grow back normally. It also doesn't grow back fast enough to keep the squirrel alive. A squirrel on its own with a broken tooth will die in the same way as if a tooth is gone. However, in very rare instances, and with many months of constant treatment by a trained professional, broken teeth can be shaped as they grow. Eventually the squirrel can have the ability to eat on its own. This has pretty much only been proven successful with baby squirrels, especially those with normally shaped mouths that have had a tooth broken due to injury, not disease.
A squirrel whose teeth have been compromised in any way must be immediately brought to a wildlife rehabilitor. Squirrels without a tooth will usually be humanely euthanized. If teeth are present, and one is broken, the vets might perform the medical treatments needed to enable it to eat normally again.
A squirrel who has had dental repair, even successfully, is never released. It won't survive. Sometimes wildlife centers will keep them and they can have a decent quality of life. There's a place near my house which has a re-habbed squirrel living in a large enclosure designed to match outdoor conditions as closely as possible. He's been there for a few years, and is used to teach people how to appreciate squirrels.
No matter what, never ever remove a tooth yourself. If it's a pet squirrel, which is highly discouraged, and in some places illegal, always monitor its teeth. They can be trimmed if healthy. Frequently they get caught in the cage, which causes problems I won't mention in detail. In the yard or wild, if you ever see a squirrel that has a broken or missing tooth; a face that appears deformed; is having difficulty eating; or is much thinner or smaller than normal, take it immediately to a certified Wildlife Rehabilitator. Those can be found by calling your vet for a referral, or in the phone book. Many websites list ways to find a Rehabilitator in your area.
I know this answer is more than the question you asked. I just thought it was interesting, so maybe other people will too.
For people who love squirrels, The Squirrel Lover's Club has a link to sign a petition against Squirrel Slaughtering. The picture is of a mom cuddling her baby, not of hunters or anything violent. WARNING: The petition page has links to some graphic hunting images. I don't know how bad they are because I didn't look at them!
Once the squirrel has reached the adult stage, their teeth do not regrow if lost.
Infant tree squirrels have three pairs of milk teeth that are replaced by adult teeth when the squirrel is four to five months old. Once the adult teeth come in, they do not re-grow if lost or removed. The baby’s lower incisors come in at between three and four weeks with the upper incisors following at five weeks.
However their teeth do grow continuously throughout their lives.
Squirrel incisors continuously grow in a highly curved trajectory throughout their lives, on average about 6 inches per year.
The front of the incisors are covered by hard orange tinted enamel that helps maintain the sharp cutting edges of the teeth. During normal eating and chewing, properly lined up teeth rub against each other (occlude) grinding down equally and evenly to the right length.