You asked and Aly answered!
We welcome back our first guest blogger: Aly Busse, director of school and public programs at Mote Marine Laboratory in Sarasota, Florida. Aly will jet by once or twice a month to answer readers’ questions about our favorite cephalopod, so keep them rolling in.
What is a cephalopod anyway?
Aly: In organizing living things, scientists use a system of classification to make sense of how everything relates to one another. It is organized from big groups (kingdoms) all the way down to each particular type of animal (genus and species). Cephalopod is the name of the Class that all octopuses are put in, along with squid, cuttlefish, and nautilus. It translates from the Greek to mean “head foot.” Don’t you think that is a perfect name for these animals?
The best part of this system is that if you discover a new organism, you get to choose the name yourself, although not after yourself—that is not allowed! Here is a great article about some really creative species naming: “What Goes into Naming a New Species? A Lot” (there is even one named after a certain Star Wars villain!).
This scientific classification isn’t finalized by any means and it changes all of the time as new critters are discovered and scientists learn more about them. For example, when I was in school I learned there were five Kingdoms of living things. Now there are six!
I really like science and I really like organization, so, of course, I love scientific classification and could go on about it for way too long!
I know that an octopus has three hearts. Can an octopus survive if one heart is injured, defective, or dies?
Aly: This is really interesting question. Let’s back up and think about why octopuses have three hearts. They do have three hearts, but it isn’t like they have one main heart and two back-up hearts!
Our one human heart does several things as it beats—it pumps blood to the lungs, where it gets rid of carbon dioxide (which we eventually exhale) and picks up oxygen (which we get from breathing in). It then distributes the freshly oxygenated blood to the rest of the body. Getting blood to the lungs is critical, since this is where it makes the exchange from waste (carbon dioxide) to good new stuff (oxygen). Two of the four chambers in the human heart do just this—make sure the blood gets to the lungs.
Now, do octopuses need oxygen like humans? The answer is yes—but they get it from the water instead of air. So, octopus circulation is set up differently. An octopus has one main heart, called the systemic heart, and two smaller hearts near its gills. The two smaller hearts pump blood to the gills, where they dump waste and load up on the good stuff, and then pump the oxygen-rich blood back to the main heart. The main heart then pumps this blood around the body. Each heart is crucial to maintaining the strong blood pressure that allows octopuses to be so active.
So, do you think an octopus could live without one of its hearts now that you know what each one does? Probably not, but just like with humans, sometimes amazing things happen!