Idk what prompted this train of thought but just imagine if a dog somehow ended up on the Normandy.
Like the crew ends up investigating some colony that was attacked and suddenly this dog just starts kind of following them around and they can’t get it to go away and Shepard makes the mistake of mentioning it to Joker over the comms and Joker is just like “Commander please you can’t just leave it… all alone.. no one to care for it..” bc he knows they’ll give in and Shepard just sighs, looks at the dog, and says “Welcome aboard.”
And of course within no time everyone is extremely fond of the dog. Like at first some of the aliens on the crew like Thane or Tali were really confused and like “Shepard??? Why is it licking me???” But then three days later someone sees Tali slipping it scraps of food while she’s on the crew deck
Liara’s reaction is pretty much like “Is that a dog?? I’ve never had the privilege to live with one before. I have heard humans hold them in high regard.” And Shepard kind of finds that hilarious
And honestly it only takes like two weeks before the dog is somehow named Shepard’s second-in-command. Someone gets it a vest that has “Normandy” written across it. Once Shepard found Jack and Ashley arguing about who the dog was going to sleep with so now they have a schedule for who the dog is sleeping with on what night. EDI teaches it commands she can give it over the intercom.
And, of course, whenever someone on the crew has a nightmare or is having a bad night or something, the dog is a pretty trustworthy crewmate to go to for comfort.
[Images are two pictures of my future service dog candidate, who is a six-week-old Golden Retriever puppy. In the first photo, he is being held and looking calmly down at me, and in the second he is itching his neck with his back leg.]