How large would the hearts in larger dinosaurs have been?

Anybody here able to give an estimated size?

The blue whale has a mass about twice that of a very large dinosaur, and Wiki gives the mass of its heart as 600kg. So 300kg would probably be a reasonable estimate.

Size please. Not weight. Guessing half the size doesn’t necessarily hold true either.

The blue whale’s heart is roughly the size of a VW bug, if that helps.

Unless you assume that a dino had a heart of meaningfully different density, the dimensions would scale as the cube root of the mass ratio.

Does heart size in relation to mass differ between warm-blooded and cold-blooded animals? I ask as there were various dino’s out there and we can tell by their pelvic structures and other physical features that some were “bird” like and others were more “reptile” like.


Well, a 300 kg dino has a grapefruit-sized heart.

Not sure of the accuracy, but here’s a brachiosaurus heart model.

The ornithischian (bird hip) and saurischian (reptile hip) distinction is merely descriptive of the shape of the pelvis. It does not denote ‘closeness’ of relation between a particular dinosaur and either birds or lizards. It dates back to the 19th century, before many (if any) paleontologists believed birds were descended from dinosaurs. In fact, there is more evidence for warm bloodedness in Saurischians than Orithischians.

Birds (Aves) are nowadays generally considered to be a subgroup within the Theropods, which are a subgroup of Saurischia. In other words, a seagull has more in common (cladistically speaking) with a “reptile hipped” Allosaurus than with a “bird hipped” Hadrosaurus (duck-bill).

This is actually a subject of debate, especially for the largest dinosaurs (sauropods).

A recent paper has shown that sauropods could and did regularly lift their necks to near-vertical position, after a decade or so of being constrained to a horizontal pose due to supposed limitations of the vertebrae. This has opened up the old can of worms about, well, if an animal had 30 vertical feet of neck, the heart would have to be incredibly massive to pump blood to the head. This is less of a problem if sauropods were cold blooded (or at least less than truly warm blooded), but still. Scientists are aware of the problem and apparently a new study is forthcoming.

The answer to the OP, right now, is we don’t know.

A rough estimate range is good enough for me. It’s just something I am curious about and don’t care if opinions change in the future.

The picture of the cheesy model helps.

Please don’t think I can run a mathematical conversion and come up with anything besides nonsense.

Thanks for everyone’s input dopers. It’s appreciated. Any future input is welcome on this subject.

Gregory S. Paul has calculated the size of a Brachiosaurus heart, but I’m not sure how up to date this would be (the link is a mailing list post with Paul discussing his calculation, in 1998).

I’m sure he published this in a more official format but I’m having trouble finding the cite.

As I said, a new paper is in the works studying this issue, and it may propose adaptations or metabolism that would allow a smaller heart.

Perhaps they only actively pumped blood to their heads when the neck was horizontal, but could maintain the blood there for short periods when they raised their heads up.