How did long-necked dinosaurs get so big?
Some long-necked dinosaurs were over 30 m long and weighed tens of tonnes, far bigger than any land animal today. Scientists think the secret was not one thing but several working together.
How big?
Sauropods, the long-necked dinosaurs, were the largest land animals that ever lived. Argentinosaurus and Patagotitan from Argentina, for example, may have been more than 30 m long, while the African elephant, today's largest land animal, weighs around 6 tonnes.[1][2]
Almost all sauropods shared the same body plan: a very small head, a long neck, a huge body, four straight pillar-like legs and a long tail.[1]
Long neck, small head, no chewing
A long neck let a sauropod stand still and reach leaves over a wide area, high and far, saving the energy it would take to move a body weighing tens of tonnes.[1]
Sauropods had peg- or spoon-shaped teeth for cropping or stripping leaves, but no grinding teeth for chewing. They swallowed their food whole and left a huge gut to ferment it slowly. The advantage: the head did not need heavy jaws and chewing muscles, so it stayed small and light enough to sit at the end of a very long neck.[1]
Bones full of air
Sauropod backbones were full of air spaces connected to air sacs, as in living birds. This made their huge bones much lighter, and probably helped them breathe efficiently and lose heat.[1][6]
Fast growth and many eggs
Bone studies show that sauropods grew very fast, many times faster than living reptiles. Scientists think this was possible because they had a high, warm-blooded metabolism rather than a typical reptile one.[1][5]
Instead of giving birth to a few big young like an elephant, sauropods laid many small eggs at a time. Even if most of the young were eaten, some survived to grow up, which scientists see as another reason such huge animals could last for tens of millions of years.[1]
Sources and further reading
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