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How to stop my 3-month-old puppy's aggression towards my dog?

Updated On September 23rd, 2025

My boyfriend and I just got another puppy. The rescue seems to think she is a terrier, maybe a jack russel mix? Anyways, we also have a dog who is two. Maggie is the new puppy. They get along fine, until my older dog gets in Maggie’s space, like accidentally lays down with a paw on her, or puts his face in hers.. Maggie will get aggressive with him. Growl and act like she’s going to bite. How do I stop this? She’s only 3 months old, so I would like to correct it now before it gets worse.

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1 Answer

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Answered By Lindsey Edwards MVB, BSc, IVCA

Veterinarian

Published on July 14th, 2018

This is not uncommon behavior for terrier types and I would expect it to settle down as they learn each others tolerances and limits. Enrolling in some puppy socialization classes would be worthwhile to help also

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