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Is my 12-week-old terrier puppy's aggressive biting normal?

Updated On September 23rd, 2025

Pet's info: Dog | Toy Fox Terrier | Female | unspayed | 3 months and 6 days old | 7 lbs

12 week old female toy rat terrier that we have had for 3 weeks likes other dogs more than us. Our gentle big dogs do not like her because she bites almost all the time. My friend says, “oh, that’s just the puppy in her.” I haven’t ever had a dog like this, though I have had several puppies. She’s almost aggressive. Is this normal?

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1 Answer

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Answered By Dr. Davis

Veterinarian

Published on December 21st, 2018

Yes, it’s normal especially in the terrier breeds. She will outgrow most of the biting by the time she’s an adult. These are very smart dogs. I would teach her to fetch so you can throw a ball long enough to wear her out. The biting should be less when she doesn’t have excess energy. Also make sure she has plenty of safe chew toys at all times. Be patient, this is a more challenging breed. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Ivy.

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