The Octopus Has Three Hearts and Blue Blood

The octopus, not satisfied
with one heart, like the rest of us,
keeps three of them tucked up inside
its mantle, without any fuss.

Two pump its blood across the gills,
where it picks up the oxygen;
the third then pushes it, and fills
the arms and body once again.

That third heart stops each time it swims,
which may be why it’d rather crawl
along the rocks on its eight limbs
than jet about the sea at all.

Its blood is blue, for what it uses
to carry oxygen is made
round copper, not the iron ours chooses,
and copper lends a bluish shade.

And though its brain wraps round its throat,
two-thirds of all its neurons lie
along its arms, which feel, and note,
and taste whatever they come by.

It changes colour in a flash
with tiny sacs of pigment, spread
or squeezed by muscles: brown, then ash,
then mottled sand, then rocky red.

Its eyes are wired from behind,
the nerves kept tidily out of sight,
so it has no blind spot to mind,
no gap, by day or dark of night.

Three hearts, blue blood, and clever arms,
a skin that paints, eyes wired right:
it’s evolution’s bag of charms,
all slipping, boneless, out of sight.