Comments on: Why don't giraffes have necks as long as a brachiosaurus?

By: Theranthrope

Theranthrope — Sat, 29 Sep 2012 11:05:00 +0000

You also have to consider that sauropods had more time to evolve light-but-strong vertebrae compared to azdarchids:

Azdarchids had only 65 million years to evolve from something roughly the size of a opossum at the time of the Cretaceous–Paleogene mass-extinction event, compared to 100 million years for the super-heavy sauropodomorphs of late-Jurassic and 185 million years for the super-heavy Titanosaurs of the late-Cretaceous to evolve from a small (chicken- or turkey- sized) bipedal carnivorous archosaur after the Permian–Triassic mass-extinction event (the “Great Dying”).

It’s an apples-to-oranges comparison: A giraffe’s dinosaur contemporary isn’t Brachiosaurus, but probably something similar to the prosaropod Plateosaurus

By: Gatto

Gatto — Fri, 28 Sep 2012 01:01:00 +0000

It feels easy to explain evolution, seeing why an adaption works; and, it’s definitely easy to invent adaptions that seem like wins, but don’t actually happen in practice. If they did have longer necks, maybe they’d be able to reach more trees without moving, or some such.
What’s cool about the paper is they bothered to analyze actual physiological reasons, and that it turn may even yield new insights, and new ideas. ( plus, hey: Giraffes! )

By: BillStewart2012

BillStewart2012 — Fri, 28 Sep 2012 00:07:00 +0000

Giraffes are tall enough for most of the available food sources in their native regions. Browsing from trees gives them access to an ecological niche that didn’t have much competition, and being tall makes it easier to see predators. Extra height wouldn’t get them significantly more food, but would make it tougher for their hearts to get blood to their heads, so it’s not a win.

By: John Randolph

John Randolph — Thu, 27 Sep 2012 21:55:00 +0000

There was a Nature or Science article some time ago that looked at the energetics of sauropods having such long necks. It turns out that pumping blood to the brain actually takes a lot of energy, but it was compensated by the fact that the sauropod could graze over a larger area with the long neck without moving, making it energetically favorable for the animal.

By: GawainLavers

GawainLavers — Thu, 27 Sep 2012 21:25:00 +0000

Because you do not want to fly into this.

By: Maggie Koerth-Baker

Maggie Koerth-Baker — Thu, 27 Sep 2012 21:09:00 +0000

Hah! I’ll fix that.

By: GawainLavers

GawainLavers — Thu, 27 Sep 2012 21:05:00 +0000

“We think of giraffes as long-necked creates…”

Only in the bible belt…sorry, had to be said.

By: BWJones

BWJones — Thu, 27 Sep 2012 21:04:00 +0000

The cervical vertebrae of the brachiosaurus are absolutely phenomenal. The world’s largest articulated skeleton is a brachiosaurus in the Museum Für Naturkunde in Berlin. Check out that brachiosaurus! http://prometheus.med.utah.edu/~bwjones/2012/07/museum-fur-naturkunde-berlin/

By: PJG Hendry

PJG Hendry — Thu, 27 Sep 2012 21:03:00 +0000

This planet was spinning faster in those days.

By: bzishi

bzishi — Thu, 27 Sep 2012 20:53:00 +0000

And why doesn’t a giraffe have wings? Wouldn’t that make it easier to get to the high up foliage?