Log #1: Three hearts, blue blood, and zero chill

First entry in the log, and I’m starting with the creature that most deserves a website of its own: the octopus.

• Three hearts. Two pump blood through the gills; the third pumps it to the rest of the body. That main heart actually stops beating while the octopus swims, which may be one reason they prefer crawling.
• Blue blood. Their blood uses copper-based hemocyanin instead of iron-based hemoglobin, which turns it blue when oxygenated.
• Most of the neurons are in the arms. About two-thirds of an octopus’s neurons sit in its arms, not its central brain. Each arm can taste what it touches.

So an octopus is, roughly, a committee of curious arms with a brain acting as chairman. Honestly relatable.

Your turn: what’s the strangest true animal fact you know? Best one gets featured in a future log.