They prepare food for animals, quality test water, help visitors during school holidays and so much more.
Taronga Western Plains Zoo volunteers have been an integral part of its success for three decades.
This month they gathered together to mark the 30th anniversary of volunteering at the zoo.
Zoo director Matthew Fuller greeted them at a morning tea and evening event where television presenter Simon Reeves was special guest.
“Volunteers play an important role in any organisation or charity and we are so very fortunate to have a dedicated group who want to support conservation and help educate our visitors about the work we do here,” Mr Fuller said.
More than 80 active volunteers at the zoo include veterans of 29 years and new recruits.