For these animals, published rates of entropy production are at most a few bits per second. That's very small compared to W, which we can estimate from their diet. And the same is true for our 𝐴. 𝑠𝑢𝑏𝑎𝑟𝑢... the bound kʙ T Σ ≤ W is quite far from being tight:

Preprint link: arxiv.org/abs/2604.00453

With thanks to my partners in crime Yu, Emmy & Ben.
And to @mleighton.bsky.social who answered many questions, and @emonetlab.bsky.social who helped with some of the data collection.

Yu Fu, Emmy Dobson, Benjamin B. Machta, Michael C. Abbott: In-vivo entropy production of A. subaru https://arxiv.org/abs/2604.00453 https://arxiv.org/pdf/2604.00453 https://arxiv.org/html/2604.00453

Disappointingly, 𝐴. 𝑠𝑢𝑏𝑎𝑟𝑢 doesn't win the prize for the weakest thermodynamic bound so far. That goes to a super-organism, the public transit system of Turin... shown to produce (at least) Σ = 2.6 × 10⁻⁴ bits/s

For these animals, published rates of entropy production are at most a few bits per second. That's very small compared to W, which we can estimate from their diet. And the same is true for our 𝐴. 𝑠𝑢𝑏𝑎𝑟𝑢... the bound kʙ T Σ ≤ W is quite far from being tight:

The entropy production rate, or irreversibility Σ, is a statistical concept intimately connected to energy: kʙ T Σ ≤ W, where W is energy per time. Nonzero Σ is impossible without nonzero W. And this Σ has been estimated in all kinds of macroscopic systems: birds, humans, cows...

Life needs energy from food, or the sun, to survive. It's a non-equilibrium process, and this fact leaves statistical clues in things we can observe. Looking for these clues in biological data is a small industry, which started by looking for closed cycles in microscopic systems:

Maybe I should tweet here too. Out yesterday is my first ever experimental paper, on a novel model organism...

arxiv.org/abs/2604.00453