The Canine Ledger

Puppy Biting and Teething: What's Normal and When It Ends

Puppies lose their baby teeth from about 4 months, and adult teeth are in by 7. What the studies say about chewing and nipping, and when to see a vet.

Written by thecanineledger

In a 2025 UK survey of families with children, caregivers were asked which parts of raising a puppy were harder than they expected. “Dealing with their puppy nipping/biting their child during play was the aspect of puppy training/management perceived to be worse than expected by the most caregivers” (Belshaw et al., PLoS One 2025).

While almost every owner gets bitten by a puppy, we found little research on how long it lasts or how best to handle it. We did find clear information on teething. This page sets out what is known, and what isn’t.

1. The teething timeline

Two sets of teeth. “Most dogs have 28 deciduous teeth and 42 permanent teeth” (Muylle, Merck Veterinary Manual). Deciduous teeth are the baby teeth.

When they come and go. “The deciduous teeth begin to erupt at 3 to 5 weeks of age, while permanent teeth usually begin to appear at around 4 to 5 months.”

When it ends. “All permanent teeth are present by the time the dog reaches 7 months of age”.

Why puppies chew. A 2025 review says that the growth and eruption of adult teeth “are believed to motivate puppies to chew in order to alleviate discomfort” (Quinn et al., Frontiers in Veterinary Science 2025). “Believed” is the authors’ word. It hasn’t been tested directly.

Chewing doesn’t stop at 7 months. The same review says dogs “are motivated to do so from the teething stage to old age.”

2. Baby teeth that don’t fall out

How common. A study of almost 3 million dogs at a US chain of vet hospitals found “an overall prevalence of 7% for PDT”, or persistent deciduous teeth (Wallis et al., Research in Veterinary Science 2024, abstract).

Small breeds most often. Extra-small breeds, under 6.5 kg, had a significantly higher rate, at 15%.

Why it matters. The authors say persistent baby teeth “are associated with malocclusion (misaligned bite), soft tissue trauma and increased risk of periodontal disease.” Periodontal disease is gum disease.

Disclosure. Two of the three authors work at a pet food company’s research institute.

Our note: The 2019 American Animal Hospital Association dental guidelines say “Immediate extraction of persistent deciduous teeth can help prevent displacement of the erupting permanent teeth that can result in a malocclusion”. They also say “A 6 mo awake oral health exam is appropriate” (Bellows et al., Journal of the American Animal Hospital Association 2019). The guidelines were supported by grants from companies, including a pet food company. If a baby tooth is still in place next to the adult tooth, ask your vet.

→ Choosing a Breed or a Mix: The Health Data Breeders Don’t Lead With

3. Nipping and biting

How many families find it hard. In the 2025 survey, 17.6% of caregivers who answered said nipping or biting of children during play was worse than expected. 45.5% said it was as expected. First-time owners were about twice as likely as experienced owners to find it worse than expected: 24.4% against 12.4%.

How long it lasts. A large UK study of young dogs found that biting, nipping and mouthing were reported as a problem for 5.1% of dogs at 6 months and 3.5% at 18 months (Kinsman et al., Animals 2025). Owners wrote in any behaviour they found undesirable, so these figures don’t show how many puppies bite. The study didn’t start until 6 months, so it tells us nothing about younger puppies.

What we didn’t find. We found no study comparing ways of stopping puppy biting.

Our note: Puppy play-biting is widely described as normal. We haven’t found a study that says when it usually stops.

Our note: We haven’t found a source on telling play-biting from something more worrying, so we give no signs. If you’re worried, ask your vet or a qualified behaviourist.

4. What to think about

  • Children. Supervise puppies and children together. The survey found nipping children was the part of puppy care families most often found harder than expected.
  • Something to chew. The 2025 review suggests suitable chews may help draw chewing away from household items. We found no trial of which kinds work best.
  • Ask for help. A vet, or a qualified trainer or behaviourist, can help if biting is causing injuries or isn’t easing.

Our note: These points are ours, including the advice on children.

→ Dog Bites and Children: Who Gets Bitten, and What Prevention Can’t Yet Promise · → Reward-Based or Aversive Training: What the Studies Found

5. What we could not verify

Commonly saidWhat we found
“Biting stops when teething ends”Not shown. We found no study linking the two.
“Teething hurts”Believed, not proven. A 2025 review says it’s believed to motivate chewing.
“Baby teeth always fall out on their own”Not always. 7% of dogs in one large US study had persistent baby teeth, 15% in extra-small breeds.
“Adult dogs grow out of chewing”No. A review says dogs are motivated to chew into old age.
“There’s a proven way to stop puppy biting”No trial found.

Sources

Always confirm with your vet before acting on anything on this page.