Sensitive museum-goers are being warned to take care near the realistic Tyrannosaurus rex unveiled in the London's Natural History Museum.
The Tyrannosaurus rex model detects prey using sensors
The 8m-long computer-controlled T.rex uses sensors to detect its "prey", can swing its tail, swivel its head, roll its eyes and open its jaws.
The £275,000 animatronic model also makes grumbling sounds.
"Once those beady eyes fix on you it can be quite unnerving and scary," said the museum's John Phillips.
"From what I've seen, parents seem to be more unnerved than the kids."
The T.rex is about three-quarters the size of an adult T.rex.
The dinosaur had one of the strongest bites of any animal ever known - about eight times more powerful than that of a modern lion.
"It makes a deep-throated rumble when it's sitting there contentedly, but roars a lot more when agitated," Mr Phillips said.
Dinosaur expert Dr Angela Milner said: "We're confident that it's pretty realistic."
Fossil remains have allowed scientists to work out how the dinosaur moved and looked.
"We even know about the skin texture from preserved remains. The only thing we're not sure about is the colour," Dr Milner said.
"It's a pretty stunning beast, and everyone's favourite dinosaur."