sauropods held their long necks straight out!??!

pellman

http://news.nationalgeographic.com/n...ong-necks.html

What a joke!

Dinosaurs couldn't possibly have pumped blood up those long necks, so they must have held them horizontal?!?!?

Hold your arm out for five minutes. Now imagine its 30 feet long.

Something was very different in the prehistoric environment, which allowed for 8 foot long scorpions to get oxygen to their innards, pterosaurs to fly, T-rexes to run, and sauropods to get blood up to their brains. I just don't know what. It's a physics mystery.

mgb_phys

The article says they could have but wouldn't have bothered, it's not worth the effort.

Different bone, joint and muscle design.
Birds can sleep with their toes grabbing onto a branch - you can't
Dinosaurs are much closer to birds.

Ancient oxygen levels are fairly well known, they were above 30% for most of the cretaceous and peaked at >35% in the paleozoic (current level is 21%)

This is a big deal for creepy-crawlies who breathe through diffusion, not so much for cold blooded reptiles.

Moonbear

It's not that much of a mystery. Modern day giraffes manage to get blood all the way up to their heads. They have higher blood pressure to pump the blood so far against gravity. I've never looked into their arterial anatomy to see if it is more muscular than arteries of species that don't have such long necks; arteries have muscular walls that helps maintain blood pressure as well.