Dinosaurs 'grew into long-necked giants to gulp food'

This has been a puzzle for researchers wondering how gigantic plant-eating dinosaurs known as sauropods got to be so big. Now, a new research has found that guzzling food let the giants get food into their stomachs quickly.

Long necks would also have helped big dinosaurs get to food without moving from a particular spot, say the scientists at Bonn University. When plant-eating mammals evolved they developed quite a different set of manners, relying on chewing to make food more digestible. "Chewing is a property which no large herbivorous terrestrial mammal has got rid of," lead scientist Prof Martin Sander was quoted by the 'Daily Mail' as saying.

A staple part of the vegetarian dino-diet was probably horsetails, fern-like plants that were abundant in prehistoric swamps and highly nutritious, say the scientists. Few animals feed on them today because they contain a lot of hard silicate which is bad for teeth. But this would not have been a problem for dinosaurs that plucked and swallowed the plants without chewing.

Sauropods are also known to have renewed their teeth frequently, sometimes as often as once a month. The dinosaurs' large stomachs and powerful metabolisms would have helped them cope with so much unchewed food, according to the scientists. Dinosaurs possessed a highly efficient bird-like breathing system involving large numbers of air sacs permeating their body cavity and bones.

"In the history of species the lungs of today's birds and of the giant dinosaurs have the same origin. Two hundred million years ago, an unparallelled combination developed of primitive traits, which were new in the history of evolution. This combination made these fascinating giants possible," said Prof Sander. The findings have been published in the latest edition of the 'Biological Reviews' journal.