Famous swooping depictions of "gentle giant" dinosaurs, such as the diplodocus, are almost certainly wrong, a study suggests.

The largest group of dinosaurs, known as sauropods, are usually portrayed in films, television and museums as having a low-necked, loping posture.

In reality these dinosaurs were no slouchers, according to a study carried out by scientists at the University of Portsmouth in Britain.

They generally held their necks aloft like giraffes, making them up to almost 50 feet tall, concludes the study, published in the journal Acta Palaeontologica Polonica.

"This new work provides plausible evidence that sauropods held their necks elevated, rather than horizontally, as had been assumed," said Mike Benton, a palaeontologist at the University of Bristol.

The sauropod group of dinosaurs lived about 150 million years ago and included the diplodocus, the brachiosaurus and the apatosaurus.

They were herbivores with small heads and big bodies, and they tended to have long necks and tails. The diplodocus could grow to 160 feet long.

• Click here to read more on this story from the Times of London.

• Click here to visit FOXNews.com's Evolution & Paleontology Center.