# Would having multiple hearts be a good solution to one of kaiju problems?

If I remember correctly, one of the kaiju problems, especially the bipedal standing, regards blood flow or circulation (but correct me if I am mistaken, I tried to find it in google regarding square cube law stuff, but I didn't find it, so now I am not sure, there's a chance it gets debunked)

So I wonder would having multiple heart can be a solution for it, or will there any bad side effect to it?

• I think you're going to have problems here. I don't know with enough certainty to make it an answer, but I believe having more than one heart in a standard circulatory system could easily cause a rupture if they do not beat in absolutely perfect synchrony. Sep 26, 2020 at 11:17
• square cube law also effects muscle strength, so no matter how many hearts you have there is still a limit Sep 26, 2020 at 14:52
• With a really big large circulatory system, there may be a way around the syncing beat issue: a biological surge dampener. In plumbing systems, to prevent water hammer when pressure suddenly increases, there's a chamber connected to the line that has an elastic lining or a piston, surrounded bycompressed air. At normal operating water pressure, the air keeps most of the water out of the chamber. When the water pressure spikes, the lining expands or piston moves against air resistance, and since air is compressible, it absorbs the shock. Sep 26, 2020 at 16:07
• @JBH what? show me where the pacific rim in it? i dont watch the movie btw but i dont see any plot or movie element in my question. Sep 27, 2020 at 7:41
• @JBH I am pretty sure that "one of the kaiju problems" refers, much like "one of the warp drive problems", to reality checks that realistic takes on those generic fiction elements fail. A "kaiju problem" is a reason why kaiju cannot work in reality, e.g. the square cube law. Sep 29, 2020 at 18:53

# Not a solution.

As per the comments in the question:

Square cube law also effects muscle strength, so no matter how many hearts you have there is still a limit.

Also by adding another heart, you now need more oxygen. This requires more lungs. You'll also need more calories, so more digestive system in general. And so on.

Just as in the rocket equation, you have diminishing returns in the advantages of being big. At some point it stops being advantageous and starts working against you.

# Yes, but not enough.

It's not simply a matter of heart. You can have multiple hearts (after all, the evolution of the kaiju is just speculative).

The pressure differential involved, both in stationary stance and when moving, cannot be overcame just by adding hearts. You'd need to completely break the circulatory system into separate sections, with a rete mirabile-like osmotic exchange for oxygen and nutrients.

Then, there are structural problems - the bones need to withstand the kaiju's weight, and the muscles need to be able to move it around. Keeping balance also becomes a hurdle when nerve signals (at 120 m/s) exhibit a lag of one sixth of a second, and it is thought that a simple fall was enough to kill the Argentinosaurus, the largest land dynosaur.