Dinosaur news - TTLG Forums

Vivian on 19/7/2017 at 12:01

My mate Karl and his team did some neat stuff on T rex which yeah, confirms earlier thought that a >5000 kg biped would explode if it tried to run: (https://peerj.com/articles/3420/)

I did some stuff showing that kneecaps in both birds and humans actually reduce the amount of force being applied by the extensor muscles: (http://onlinelibrary.wiley.com/doi/10.1111/jzo.12485/full)

I AM VERY SMART etc

Viv

Thirith on 19/7/2017 at 12:50

And here I thought that the thread title referred to the people dismayed by the recent Doctor Who announcement. :p

Also, what's the point of a T. Rex if it can't run? :mad:

Kolya on 19/7/2017 at 13:06

Did he consider comparisons to the spring function of tendons and muscles in kangaroos that transfers the energy from the landing into their next jump?

//P.S. I'm also very smart.

Kolya on 19/7/2017 at 13:15

He should also consider that a scientist who proves that T. Rex can't run is bound to get snacked out of a Jeep going at full speed through a Pleistocene jungle.

And now for something completely different:
[video=youtube;5l8-nD2T4Mw]https://www.youtube.com/watch?v=5l8-nD2T4Mw[/video]

Vivian on 19/7/2017 at 13:24

Their take on it was bone stresses this time round, rather than issues with energy cycling or power requirements. Making their simulation move fast (or use any running gait) produces a failure load in the bones. I'd imagine they have terms for passive storage and return yeah, the GAITSYM system they've got is a full-fat musculoskeletal dynamics solver. They know their stuff.

Also the pleistocene? A jungle in the pleistocene? A t rex in a jungle in the pleistocene? You are WAY out.

Kolya on 19/7/2017 at 13:26

You forget there's also a Jeep.

Vivian on 19/7/2017 at 13:31

If the jeep is a sledge, the jungle is basically not there, and the T rex is a short-faced bear, I'd agree with that. I might get eaten.

demagogue on 19/7/2017 at 14:25

What did they eat that doesn't involve running but sustains that kind of body?
Are carnivore megafauna that aren't able to run a regular thing in nature?

Neb on 19/7/2017 at 14:34

You wanna come over here and say that to my face?

...scavenging the other big dead things?

Vivian on 19/7/2017 at 14:57

A lot of other things were also very very big, and hence also relatively pretty slow. I guess they just walked after each other? (But walking is still pretty quick when you have legs 2m long). Unfortunately there is nothing really extant to compare them to. The polar bear is the biggest terrestrial carnivore and that's only like a ton, max (and they swim a fair bit). Scaling of speed is a pretty big topic, and while speed should increase with size it tops out in medium-sized animals. Square:Cube tissue stress scaling is probably a big part of it, but there's an interesting recent paper on acceleration times and available anaerobic energy: (https://www.nature.com/articles/s41559-017-0241-4) (might be paywalled, sorry). The gist is that large animals can get round the power limit by using longer acceleration times, but hit a metabolic limit with the duration they can sustain max effort for.

T rex was a scavenger, yeah. Pretty much everything else in the world is, so it would be weird if it wasn't.