Pig
The pig, also known as swine or boar, is a highly adaptable and intelligent animal present all across the Fifth World. Some descend at least partly from formerly domesticated pigs gone feral after collapse, but many descend primarily from wild pigs.
#Human usage
People of the Fifth World hunt pigs for their meat. They also use their hair for brushes.
#Specialization
A community specializing in relationship with pigs may or may not practice horticulture, living in settled villages. They may form strong bonds with certain pigs, and have a tradition of hunting truffles side-by-side with their pig friends.
They will almost certainly not practice any form of Islam or Judaism, unless their variation on that faith has diverged wildly from its historical stance on pigs.