Where are the crabs and boars? Rare it's time!
Nuff said.
To be fair, adding a boar skin to the existing pigs (and maybe a charge animation) doesn't seem outside the realm of possibilities.
That said, sadly, I don't see Rare dedicating ressources to crabs (or any kind of new animal) as wildlife or as legit pets, they seem to be already struggling with their current timetable, workload and what they've planned, and the game barely holds together as it is...