It’s no surprise that larger animals require more food. African elephants, weighing up to 12 tons, devote sixteen hours per day to eating. How were 50 ton sauropods able to find the time to gather the amount of food they must have required each day? The answer lies in their long necks. The long necks allowed these animals to gather vegetation by sweeping their heads across vast regions, rather than by expending the energy required to move their enormous bodies.
Unfortunately, most animals cannot support their heads on long stalk-like necks. Elephants, to go back to our earlier example, have massive heads supporting huge grinding molars. These molars are essential for chewing and crushing the elephants' food. Sauropods got around this obstacle by not bothering to chew their food. Gulping down vegetation without chewing allowed sauropods to evolve tiny, light heads, which could easily be supported by their long necks.Chewing does have advantages, not least of which that it allows greater absorption of nutrients, especially from plants. Apparently, the sauropods were able to get enough calories to sustain themselves even with less complete digestion.