bat scientists are called Chiroptologists
A herpetologist works with reptiles and amphibians. This includes snakes, lizards and frogs.
Cattleman or cattlewoman. Not farmer because not all farmers have cows, and it wouldn't be "producer" either because we're talking about someone who works with cows, not owns them.
You would call someone who looks after sheep a shepherd.
Oneirogmologist
machines
someone who works for a business
An employee
A gardener.
demonologist
a horticulturalist
collector
Mason
coach
A person who works with gold is called a goldsmith.
Chemist
An Optician x
A co-worker. or colleague