It will probably come to pass that if you open a tavern, a select few races might have the priviledge of exploring rumors of your site by taking to the air or seas (amphibiously) using a exotic animal or using a horse to increase the speed & distance of where they come and go so what happens to all the animals afterwards?
Location - Pasture is simple in that all animals located there are regarded as 'guests' and if they do not graze peacefully being pastured above grass, dwarves will bring out food to feed them if they have a enabled animal caretaking job acting almost like valets (cheatily allowing you to pasture your own animals for round the clock feeding like elk-birds or grazing empty embarks), theiving fortress mounts can also be a crime and travellers may have parked their 'get-away vehicle' here, rather than jog all the way off map.
In adventure mode, designated tavern pastures allow you to leave your animal comfortably out of sight visiting a world generation establishment, and when people visit your built tavern, the patrons will similarly leave the animals there to come inside.
- Peddlers might arrive with some wares on horseback, and then flog assorted *tat* like ear-rings to dwarves inside the tavern, until economy is re-enabled, a dwarf might simply trade a trinket they are already wearing or in their personal chest collection, raising their social skills and potentially upscaling their possessions if they're very persuasive. Once dwarves have a allowance for fort mode they can pay coins like adventurers do.
- For obvious reasons, while most barkeeps might tolerate very tame [LARGE_PREDATOR] mounts or pets they will not allow you to park up undead or any description of [MEGABEAST] outside of their tavern for fear of scaring the patrons and public property damage, cancelling it out from fortress mode & shouting in a text box a few generated complaints when they try as a adventurer
- Inside the tavern, some mounts can be marked as 'for sale' hitched ouside and bought by finding the seller and negotiating, and you can sell your own mounts for a profit depending on whether they have pet value to save slaughtering ones you don't want or can find a purpose for.
Important bugfixing note - Animals who are displaced by traders such as, 'wagons' can wait in the locational pastures, and in a way it serves as a sort of 'parking lot' for when they are waiting their turn to enter a already occupied trading depot providing they have room to move, wagons will become static and inactive until they have somewhere to go when the traders come to recollect them.
Animals who's masters who've died can be confiscated after a period of time has elapsed and they become fortress property.