December 26, 2015

Did you know that an octopus has three hearts, nine brains (ok maybe not brains like the way we think of a brain but ganglions), and blue blood? Two of the hearts are branchial hearts, which pump blood through the gills. The third heart is the systemic heart, which pumps blood through the body. There is a central brain and eight ganglions (large bundles of nerve cells). Each ganglion is located at the base of an arm. Their purpose is to control movement. The blue blood is caused by red blood cells using copper instead of iron to bind oxygen molecules. So while mammals use hemoglobin, the octopus uses hemocyanin. (Another example of an animal with blue blood is the horseshoe crab.)