Mac gives me the vibe of someone who has the bad tendency of stealing animals, not just to sell them, but to keep them as pets.
It started off with Lil' Bow that he grabbed off of some bounty hunters then it turned into Lil' Bow and Junior. Junior is an ex-feral barn cat he found one day when drunk and he had broke into a barn to sleep it off. In his drunken haze he thought the kitten looked and acted like Javier with all its attitude and little moustache. Once it was finally morning he brought it back to camp with him and gave it a bath before handing it over to Javier, boasting about calling it Javier Junior because the two are like two peas in a pod. At first Javier and Junior do not get along because Junior is a feral, feisty kitten that only knows to survive but after enough nights he becomes Javier's loyal little follower. There is a reason Micah keeps finding all his clothes ripped after throwing slurs at Javier.
The next pet is one Mac steals from the O'Driscolls after Dutch had given him a job to go out and interrogate some to see if they knew anything about Colm. Instead, he found that Colm had brought some illegally smuggled dogs over, just small puppies that could be trained to be killers to help out the gang and attack the Van Der Lindes or the law's own dogs. Once killing the O'Driscolls he sets all the pups free, except for one. A shivering, scared runt with an obviously injured leg. He picks it up and takes it back to Kieran, the two using their combined horse knowledge with Bill's dog knowledge to fix up the pup who Kieran names Aine after his mother due to how gentle the pup is. It surprises them when Aine grows to be larger than Bow, as none of them realised she was an Irish Wolfhound.
The last pet he steals is technically two. One for him and one for Davey. As Arthur, Hosea, and Dutch were conducting one scheme in Saint Denis, Mac was made to watch guard over the docks with Lenny and Sean just in case some wealthy traders were at the docks that could be easily robbed. This is when Mac sees one ship that immediately draws his eye, a ship from Europe that is holding all sorts of hunting dog pups for the wealthy to buy to show their status on elaborate hunting trips, normally Mac would not care too much about stealing any of them. But, on one of the signs he say an interesting name. Back when Mac's parents were still alive they owned a few Scottish Deerhounds that Mac and baby Davey constantly played with and it just so happens that the ship had a couple. He somehow convinces Lenny to help him while Sean creates a distraction, grabbing two pups for himself before running off. He names his Faolan while Davey names his Torcall, like after the dogs they remembered having as children.
Most days you will see Lil' Bow, Junior, Faolan, and Aine curled up together while Torcall plays with Cain. Dutch puts a ban on Mac stealing any more pets but he is thankful that now they have something to deal with the rat problem and to help with hunting.
I have more headcanons for the pets but I have rambled on long enough.
Mac acts all tough and manly and rude but inside he's an animal lover, and if he wasn't doomed to be an outlaw he would've loved rescuing animals...like he finds a baby bird that's fallen off a tree, and he's figuring out how to get his gigantic self up the tree. usually he ends up asking Sean who isn't the best climber, but he's smaller, so Mac can basically throw him up.
He's just the type of person who prefers animals to people, and will go on rants about it if he's offended with some gang member.
'see? a dog wouldn't do this to me, yer all a bunch'a assholes, 'm going back wit my babies' and he picks up whichever pet is closest and calls for the rest. The animals happily follow him...like an evil disney princess.
Davey also likes animals, but not HALF as much, which lowkey offends Mac sometimes. he's like 'WDYM THIS ISNT THE BEST THING EVER?' and it's the ugliest baby chick you've seen. Davey grimaces and says 'Mac im happy fer ya but if ya don't get that wee shite away from me i'll smack it into the sun' and Mac is this close to starting a brawl w Davey.
