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I don't understand how the square-cube law is relevant here. The volume of blood indeed scales cubically with the length, but so does the volume of the heart. Where is the quadratic part of the equation that limits the maximum size of a whale? Why would it not work to take a whale and arbitrarily scale it in photoshop?

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> Where is the quadratic part of the equation that limits the maximum size of a whale?

Muscle power output increases with cross section area, ~L^2, not with volume. The heart have no separate power unit. It relies on the same muscle walls that comprise its chambers to power itself.

That just means the walls of the heart would need to grow thicker. Are they at the limit already?

Wall thickness increasing by x increases cross section/power by x^2, but also increases chamber volume/workload by x^3. So workload outruns available power. It's because of this people abusing steroids get heart failure eventually.

>chamber volume/workload by x^3. So workload outruns available power.

What do you mean by workload? Are you referring to the oxygen cost per stroke, or what?

Power demand. Volume pumped each cycle * (systolic pressure - diastolic pressure) / time.

Mate, I have no idea what you're saying, or how it's a constraint on size.

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