Most breeds seem to have a trait they all come with, such as German Shepherds being smart.

You may not want a stubborn dog, for they're hard to housebreak. You don't have to befriend them, and it seems you can adopt more than one. You can use 'get to know' on them, learn their traits, and decide which of them you'd like to keep. There you can opt to pay $200 to have an animal care worker visit your home and show off up to three animals. You'll find the option to adopt a cat or dog under the 'services' menu on your Sim's phone. Getting a Pet Adopting a Cat or Dog Adopting a Ghost Cat from the Brindleton Bay Pet Cemetery (see bottom of guide) Despite the differences between the two species and their behaviors in reality, a lot of what goes into caring for them is the same when it comes to owning pets in The Sims 4. Caring for them is not much different than in reality - feed them, go to the vet, provide them love and make sure they're happy. Sims can have fun with pets, build relationships with them, and enjoy socializing with their companion animals. This should help newer players to understand how to take care of a pet and the realities of owning one.

I say that as a pure gameplay guide writer, because it's not exactly easy to write about how owning pets works in terms of gameplay. Owning a cat or dog in the Sims 4 Cats and Dogs Expansion doesn't add major gameplay changes mechanics-wise, they're just a great household addition. The Sims 4 Cats and Dogs Adopting, Training, and Caring for Pets

Sims 4 pet mods cats