Triceratops: Which way should my horns grow?

A huge creature with a small brain, the Triceratops apparently had a difficult time making up its mind which way its horns should grow: upward, backward or forward.

Triceratops was a plodding plant-eating dinosaur easily recognized by its great bony head frill and three horns: one above each eye and one above its beaklike mouth.

It lived during the late Cretaceous Period, making it among the last dinosaurs to evolve before their demise about 65 million years ago. An adult could grow up to 30 feet long and weighed up to 5 tons.

The horns of adult Triceratops grew up to 3 feet long and the forward curvature marked their owners as sexually mature, the researchers speculate.

"More than likely, it has something to do with display," said John R. "Jack Horner of the University of Montana. "To let adults know when juveniles finally reached sexual maturity."

Researchers Horner and Mark Goodwin of the University of California, Berkeley examined the skulls of 10 Triceratops that died at different ages, including recently unearthed baby and juvenile specimens. The baby skull was just over a foot long, while adult skulls were more than six-feet in length.

The horns on the baby were only about an inch long. But the horns lengthened and curved as the dinosaurs aged: backward for juveniles, straight for young adults, and finally, forward for adults.

Triceratops' bony frill also changed with age. In juveniles, the frill edge was crowned with triangular bones resembling arrowheads. The spiky edges flattened as the animal aged and were barely visible in adults.

It was once thought Triceratops used its horns as weapons against predators like Tyrannosaurus rex. But most paleontologists now agree that the elaborate adornments of many dinosaurs such as the bony plates of Stegosaurus and the odd head crests of duck-billed dinosaurs, were used for species recognition or mate attraction, much like colorful feathers in birds.

Source:Xinhua/Agencies