How did they drink?

I just have a hunch that most reconstructions of large dinosaurs, the sauropods in particular, can be shot down in flames by asking incredibly simple questions such as: ‘How did they drink?’ or ‘How did they sleep?’.

All animals need to drink more than they need to eat. However, since diets are incredibly varied across the animal kingdom, it is of great interest to researchers, not the least to paleontologists. Therefore, a lot of attention and discussion is focused on feeding, perhaps to the extent where we forget the more mundane essentials such as drinking and sleeping.

I get it. It is boring to ask how a colossal animal drank compared to how it could possibly have been able to eat enough food to grow this big, what type of food it ate, and how it ate it.

This may just be my impression, though. Perhaps the scientists do have all the essentials in mind when they model the skeletons of extinct animals. I may very well be mistaken.

But still…

Take the debate about if sauropods – the long-necked dinosaurs – could reach up to the highest tree crowns or not. Their clearly herbivorous diet and long necks intuitively suggest that they evolved to reach high. However, there are several problems with this.

First of all, raising a long neck high up would take considerable muscular effort, and would require the neck to be flexible, which further means that lots of muscles would be needed along most of the neck to hold it stable, at any height. Therefore, it has been suggested that the sauropods alternatively had stiff necks held just above ground level using elastic ligaments, which would not be able to elevate the neck, but keep it from falling without any energy effort.

But, while this seems to have gained wide acceptance (probably based on actual evidence of such ligaments on fossils, I guess), an idea that the sauropods might have stood up on their back legs, in order to reach higher, spread. Again, critics pointed to the fact that it would require enormous muscle work for an animal of that size to pesade, and to remain with all its weight on only its hind limbs. Some suggested that they could have used their tail as a third leg, assuming what is termed a tripodal posture. However, that would not really make the labour effortless.

My point is, it seems so much attention has gone to figuring out how they could reach up. I have not read a single comment about how they would have lowered their heads to drink water. Unless they drank from waterfalls or steep-sloped streams, they would have needed to get their heads down to ground level regularly.

Anyone who has gotten up from a sitting or lying position and felt dizzy is aware of the effect of raising your head too quick. Imagine raising your head 10 metres in a swipe. I think I wouldn’t get any blood to my brain and I’d faint halfway.

Maybe you think that the sauropods probably raised their heads very slowly. Consider, then, how vulnerable they would have been if approached by a predator while drinking?

Actually, that thought reminds me of what I read about giraffes: when they drink, they must spread their front legs in an incredibly awkward position, in which they are extremely vulnerable to e.g. lions, because they take too long to get up from that state. This is because the giraffe neck is stiff and its front limbs are longer than the hind limps. This is exactly the same design as in the sauropod Brachiosaurus (although not in many other sauropods) As an inevitable result, the neck cannot lower down comfortably, and they have to bend their bodies over.

Having that in mind, and that most sauropods had shorter forelimbs, I am happy to accept the idea that they had stiff necks held up by elastic ligaments, and muscles that were able to lift or sink it slightly. The forelimbs being shorter than the hindlimbs means that the neck would generally be angled down toward the ground. If we further consider the long neck as an adaptation to reach down to the ground without the need to bend the (still rather long) front leg, it can explain why they evolved their long neck in the first place. It challenges the intuitive assumption that the length of the neck evolved in response to pressure to reach higher than anyone else could reach. It implies that the sauropods may have grazed and browsed mainly 1-2 metres above ground level.

I really like that scenario, and I find it makes good sense.

There is still the question of Brachiosaurus and how that beast would have managed to drink. 

The take-home message of this post is about the need to think about the boring, yet essential aspects of all living organisms, if we want to truly understand their lives. We need to be open-minded and not get too buried in the exciting questions: you might even find an easy answer by looking at something else that seemed boring at first!