Here is a short devlog about changes coming to workers.
In the current version workers will do all the jobs they encounter. In the next update there will be an option to toggle certain job types from the workers so you can have dedicated cleaners and so on. Each tier of workers have also limited skills which limit the types of work they can do. Low tier works can do only simple tasks while high tier workers can do everything.
The following workers are the only ones currently planned to be in the game and they will be in the next patch.
Goblins
Theses are the basic cheap starting workers. Goblins know the basic jobs and keep the zoo running. Though, they can not do the more advanced jobs, like capturing escaped animals alive. While working in staffed buildings, goblins lower the revenue of that building by stealing some of the profits.
Skeletons
Skeletons require no wage but instead require some mana. They are meant to be super cheap but bad workers. They mainly can clean the zoo or staff buildings. Skeletons also lower slightly happiness of the guests who see them, since seeing undead too close is not that fun for most.
Humans
Basic workers with a medium wage. Humans can do all things that zoo requires. While staffed in buildings they will slightly increase the revenue of the building they work at.
Mage
Mages are the high-tier workers and require high wage. Mages can do their work from a small range away by casting spell and do it fast. While in buildings they increase the revenue and boost slightly guests happiness.