I'd like to play a zoologically-oriented safari-type fort one of these days, but I got discouraged when I read that it wasn't yet actually possible to domesticate an animal to the point where it shows up on your civ's embark supplies. This would be a cool thing to have. Another cool thing would be discovering new species that your civ never knew about before, but once you've seen/heard of them, your artists can engrave them (with the level of accuracy depending on just how familiar your civ got to be with them: has anyone seen those ancient European drawings of "elephants"?) Basically, enabling a "gotta catch 'em all" style of play, somehow, with results that extend beyond the single fort.
It'd also be cool if the animals had some of their other historical uses, such as beasts of burden and mounts. Beasts of burden might be the easiest of these to implement, I assume, as it's essentially Hauling jobs being enabled on certain species. I'd recommend, though, that they actually function the same as a wheelbarrow: a Dwarf must load the creature up and guide it to its destination. Max Load could be determined by the animal's strength/size, making elephants prized and squirrels hilarious.
Perhaps mounts would be handled that way, with a mount essentially hauling a dwarf rider. Or, there could be complications like a Riding skill and/or requiring a saddle, with poor quality of either causing risk of falls and injury (based on height of animal and speed of travel). Maybe riding "bare-back" would generate an unhappy thought ("Urist McSorebottom was forced to ride without a saddle") while expensive saddles would bring a postive one ("Urist McRider rode in luxurious style today"). This also brings up mounted fighting, of course.
Thoughts?