It is a truth universally acknowledged that puppies chew--good puppies chew on their own things; bad puppies chew on everything. But, why do puppies chew? Though there are a number of social and developmental explanations for oral activity in puppies, quite often the answer is simple: puppies chew because they have teeth--lots and lots of teeth. Some teeth are coming in and others are falling out, but all of them are sending signals to the puppy's brain that it's time to chew.
Canine Dental Development
Just like human children, puppies lose their baby teeth. Between the ages of 4 and 6 months, those needle-sharp puppy teeth, often called "milk teeth" or "deciduous teeth," begin to fall out as they are replaced by a stronger set of adult choppers. Usually, the front bottom teeth--the incisors--are the first to go. They're followed by the upper incisors. Then the bottom and top premolars--the first few teeth that line the jaw from front to back--are replaced. Finally, the new canines and the larger molars at the back of the jaw will erupt.
Signs a Puppy is Teething
Increased chewing. While all puppies chew, the nature of the chewing changes when a puppy begins to teethe. Tussling with toys and other playful behavior may start to give way to serious gnawing. The puppy whose attention span once resembled a hummingbird's flight plan will suddenly have the focus of a Zen warrior. This warrior puppy will settle down with a beloved toy (or half of someone's favorite pair of shoes) and not stir until the object of its attentions has been systematically shredded into confetti.
Blood. While it can be scary if you're not expecting it, a bit of blood coming from a puppy's gums during teething is normal and harmless. Orally active puppies may dislodge a loosened tooth, and the gums around the tooth may bleed. The bleeding should be nominal and resolve itself in short order. If it does not, a visit to the veterinarian is in order.
Aggression. As the teeth begin to fall out, the puppy's personality may begin to change. As the adorable, eager-to-please furball is compelled to mouth everything in its sphere--including its human companions--questions about authority and pecking order pop into the canine mind. What began as teething-driven mouthiness can quickly turn into nipping and even biting if not properly addressed. If you feel like you're losing the battle, it's probably time to sign up for a puppy obedience class.
Physical distress. Whining, apathy and diarrhea may appear. For some puppies, teething can be quite painful, and they respond as they would if they had any other physical ailment. A teething puppy may whine for no apparent reason. Puppies in pain may become apathetic and less interested in playing. There may be a disruption of the puppy's digestive tract--the puppy's appetite may wane and bowel movements may become loose and watery. If the puppy's distress appears to be anything other than mild, or if there is any reason to suspect a cause other than teething, consult a veterinarian immediately.
What to Do When Teething Begins
Do not get mad. For your puppy, chewing is compulsory. It is your job to recognize this and ensure that those energies are properly channeled into acceptable pastimes. Simply using punishment to deter inappropriate chewing would be like punishing your child for growing too tall for his pants.
Do not leave your puppy unattended. Nothing is sacred to the teething puppy. Your shoes, your socks, your rugs, your couch, your speakers--if something is within reach of the unattended puppy, at the very least, it's vulnerable to teeth marks.
Do give your puppy plenty to chew on. Look for things that are interesting and challenging to chew on. A damp rag rolled into a log and popped into the freezer becomes a chew toy that can help soothe a puppy's sore gums. You may also want to consider laying in a large stock of rawhide chews, dried pig ears, dry dog biscuits, large-animal soup bones, firm rubber toys, sticks of kindling and knotted rope.
How Long Does Teething Last?
Teething generally lasts for several weeks. Understanding the process and preparing in advance will allow you to help your puppy get through his or her pain and discomfort without harming the relationship you're trying to build.
When to Go to the Veterinarian
Occasionally with all breeds and more frequently with some (especially the toy breeds), a puppy's adult teeth may erupt before the milk teeth have fallen out, and it may be necessary to take the puppy to the veterinarian to have the unwanted milk teeth removed. This should not be delayed. Milk teeth that remain alongside their adult counterparts can negatively affect the final alignment of the adult teeth (creating a malocclusion) and the close-coupled teeth can accelerate tooth decay.