When a woman wrote to Erth to complain that their lifelike dinosaur puppets had terrified her grandson and he couldn't sleep, the theatre makers felt they had done a great job.
''We can't really apologise because we're just doing what we're supposed to do,'' Erth's artistic director, Scott Wright, said.
''Everybody knows dinosaurs can be scary and they eat each other, so we don't pretend they're anything different … It's not a shopping centre with Dorothy or Barney.''
The Sydney visual and physical theatre company doesn't go for cartoonish dinosaurs, instead consulting with paleontologists to emulate the real prehistoric creatures.
Rapt fun typically outweighs the fright factor among children at Erth's popular ''petting zoo'' shows. But as one boy told them: ''It was so exciting to be terrified.''
The company is making its debut of the show on Broadway in January and then touring the US. But first it is staging its biggest version, Dinosaur Petting Zoo - Goes Rogue, this week at Carriageworks in Eveleigh as part of the Sydney Children's Festival.
The festival has performances and workshops in venues around Sydney for school holidays.
The show's rogue element means ''it's more dangerous - we've upped the ante and put more dinosaurs in the room,'' Wright said.
There will be territorial battles, recently discovered Australian dinosaurs and Erth's first underwater segment.
Having all the dinosaurs the company has made in the past dozen years in one place is rare, enabling up to 14 dinosaurs to be on stage at once in a ''super show''.
Erth has had its creations used in everything from films to festivals and Sydney's Olympic opening. In the company's workshop, an Aladdin's cave with dinosaurs hanging from the ceiling at Carriageworks, Wright steps inside an australovenator dinosaur to demonstrate how the recently discovered Australian predator is brought to life.
''Australovenator hugs its prey with its big claws - and then it tears them in half,'' Wright says. And he relishes telling wide-eyed children.