"It takes a village" is something of a cliché, but like most clichés, it gets used so much in large part because it is very true. I often think of running a zoo like running a small city - even in the smallest of towns, you need a people with different jobs to make the place function. Many of those jobs are fairly similar across communities, but will just vary by scale. A small town might have a single constable, as opposed to a big city which might have an enormous police force. In some towns civic leaders might wear many hats, each of which would represent a separate department in a bustling metropolis.
It's similar in zoos. Some zoos might have three or four keepers, others might have one hundred. At some facilities the registrar might also be a vet tech or curator; a very big zoo might have a dozen vet techs, half a dozen curators, and two or three registrars. Some roles have a bigger part to play in some institutions than others; even a small aquarium will need to put more focus on life support and water quality than a large zoo that doesn't have any aquatic exhibits. Bigger zoos see more specialization. Smaller zoos really get their mileage out of the phrase "Other Duties As Assigned," to the point where it almost became a mantra at one of the smaller places where I worked.
In many ways I did prefer working at a smaller place, where there was much more variability and novelty in the work. At the same time, it is also kind of nice being at a bigger place where there are opportunities for specialization and perfecting skills. Most of the jobs that I highlighted this month have been ones which would take place in a mid-sized zoo with some specialization, with separate departments. All of them represent tasks and jobs which need to be done for the management of a successful zoo, whether they are a shared responsibility or a separate team.
Compared to the keepers, many of these jobs don't take place in the public eye, and aren't as celebrated or discussed as often as the work of a zookeeper. All of them, however, are important for the success of the zoo and the care of the animals that live there. We celebrate National Zookeeper's Week every July (the Vet Techs have their week in October), but no one celebrates the commissary steward, the registrar, the behavioral specialist (and I've seen some pretty catty keepers get indignant when their zoo has tried to slide those folks under the umbrella of NZKW, feeling it cheapens "their" week).
So, just to say it here, there are no small jobs in the zoo - and that's including the jobs which I didn't focus on here and are even more further removed from the animals, from admin to guest services to custodial. Everyone has an important job in making the zoo what it is.