The 54-year-old man from Perleberg Zoo, located in northern Germany between Berlin and Hamburg, was cleaning the camel enclosure on Sunday morning and feeding the animals when one turned suddenly and bit him, police said.
Police described the injuries as “serious” and said the man, whose name was not released, was being treated in a local hospital.
The zoo is currently closed according to German coronavirus lockdown restrictions.
It comes after a zookeeper suffered serious injuries at Madrid Zoo Aquarium when he was attacked by a 200kg gorilla in September last year.
The 46-year-old employee entered a "bounded area with a triple door" for routine feeding and cleaning at about 10.15am when the 29-year-old animal, named Malabo, attacked her, the zoo said.
Another zookeeper in Australia was left with critical injuries after she was mauled by two lions in May 2020.
The keeper, named locally as Jennifer Brown, 35, was cleaning the animals' enclosure at Shoalhaven Zoo on May 29 when she was mauled.
The incident left Ms Brown fighting for her life with head, neck and facial injuries.
A health and safety investigation was carried out at the zoo after it was announced that the two lions would be spared.
Additional reporting by Associated Press.
