Unknown people broke into the Adelaide Zoo on Sunday night and killed 64 animals.
Zoo officials said the slaughter was concentrated in the children's zoo, where sheep, rabbits, goats, guinea pigs, an antelope, a llama and eight hand-raised baby kangaroos were slain.
Three flightless rhea birds and a six-foot-long alligator were killed in another part of the zoo. Most of the animals, almost all of which were tame, were either beaten to death or had their throats slit, police said.
"It must have taken several people to inflict the kind of damage that was done," zoo director Robert Baker said. "It was very, very malicious and cruel."