The model dinosaurs were beheaded by mystery vandals who scaled a fence and removed the parts using an angle grinder or hacksaw, ACT Police said Tuesday.
The hunt is now on for the attackers, after the incident on Saturday night, which took place in the Canberra venue’s outside display area.
"The damage sustained to the three dinosaurs indicate that an angle grinder or hacksaw was used to remove the heads from the body," police said.
"The offenders had climbed a four-foot fence to gain entry."
Museum staffer Mitchell Seymour said the damaged dinos were first spotted by visitors, and children were left puzzled at what happened.
"We went out to check it out and three of our dinosaurs here have been decapitated," Mr Seymour told the Australian Broadcasting Corporation.
"We had heaps of kids coming up and going 'oh mum and dad, what's wrong with the dinosaurs?'
"It's selfish, and it's thoughtless is what it is."
A giant fibreglass dinosaur was stolen from the museum in 2013 and later found in the home of a man who said it was taken as a birthday prank, ABC reported.
Police have been searching for the vandals since Sunday and have since released CCTV calling on the public to help.
Footage shows a 4x4 dual cab ute drive along the western side of the building.
Police allege that the occupants of the vehicle are responsible and urged anyone who has any information or saw suspicious activity around the National Dinosaur Museum on Saturday night to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website quoting reference 6137157.
Information can be provided anonymously.
-With AFP
