While reading the book "The Soul of an Octopus" by Sy Montgomery, I learnt that Octopuses have three hearts. This is very fascinating. According to a Wikipedia article, two of the three are used to pump blood through each of the two gills while the third pumps blood through the body.
So, my question is can an Octopus survive if one of these hearts stops functioning?
The Wikipedia entry you linked and the other answer both state that…
… the systemic heart is inactive while the animal is swimming and thus it tires quickly and prefers to crawl.
I tried to find an accurate source corroborating this (by accurate I mean a paper in a peer-reviewed journal or a zoology book), but I couldn't. The best source (scientifically speaking) I found was this page from the Smithsonian Institute, which says:
Octopuses have three hearts. Two of the hearts work exclusively to move blood beyond the animal's gills, while the third keeps circulation flowing for the organs. The organ heart actually stops beating when the octopus swims, explaining the species' penchant for crawling rather than swimming, which exhausts them.
A much more reputable source is Octopus: Physiology and Behaviour of an Advanced Invertebrate. It says:
If an octopus is surprised by a sudden movement on the part of an observer, or a thump on the side of its tank, the systemic hear may miss one or more beats.
Which is, evidently, way less dramatic than having one of the three hearts stopping.
The same author says, talking about Octopus vulgaris:
Together with changes due to exercise and arrests attributable to sudden tensing of the body musculature, any prolonged recording reveals apparently spontaneous changes in amplitude that are not obviously correlated with anything that the animal can be seen to be doing. From time to time the heart stops for several seconds (as it does, for longer periods, in O. dofleini).
Thus, apparently, the maximum we have here is periods longer than several seconds (which the book, unfortunately, doesn't determine more precisely).
In conclusion, despite their circulatory system being very complex and the systemic heart being able to stop beating for several seconds (or during the whole time of swimming, as the Smithsonian says), it doesn't seem possible that octopuses can survive if one of their hearts stops (forever). Have in mind that the hearts are not redundant, that is, one heart cannot perform the function of the other (if that other one stops).
Source: Wells, M. (2013). Octopus. 1st ed. [Place of publication not identified]: Springer.
I heard that when some octopuses swim, their third heart (which pumps blood through the body) stops, which is why they tend to crawl.
I only heard it, though, and I haven't verified.
Can an octopus survive if one of its three hearts stops working? - Biology
Suckers: Each arm of the Pacific octopus contains about 280 suckers. The suckers play an important role in both the octopus&rsquos sense of touch and taste. Each sucker is believed to contain thousands of chemical receptors. The rims of the suckers are a particularly sensitive area to touch. It is expected that a blindfolded octopus could differentiate objects by sense of touch as easily as the octopus could sense an object using its sense of sight. The suckers are also able to create a suction and grip onto prey or the substrate.
Hectocotylus: This is a reproductive organ found only on the male octopuses. It makes up a male's third right arm. This arm stands out because it is the only arm that does not contain the full amount of suckers. The last fifth of the arm, instead, has a ciliated crease running down the center. The terminal portion of the hectocotylus is called the ligula, which contains erectile tissue. The ligula does not have any chromatophores, however, so males frequently keep it curled up to maintain their camouflage. More details of the male's use of the hectocotylus can be found on thereproduction page.
Statocyst: The statocyst receptors are used by this octopus to detect angular rotation. They are able to use detect rotation in three planes, at right angles to each other. This way the octopus determine its body&rsquos orientation in relation to the ocean floor. It uses hair cells, along with gravity, to complete this task. It may also use these hair cells, along with vibrations, to &ldquohear.&rdquo Octopuses have been found to be most sensitive to lower-frequency vibrations.
Eyes: Pacific octopuses have very advanced eye structures. They contain many of the parts that human eyes do, including: the iris, the pupil, the lens, the retina, and the optic nerve. However, the pupil is not a round shape, but is a horizontal slit. When focusing, the octopus&rsquos eye moves the lens forward and backward, instead of altering its curvature like humans. The eye i s one of the most important senses to the Pacific octopus. It uses its sense of vision to choose a mate, find a den, blend in with its environment, and locate prey.
Brain: This invertebrate is a very intelligent creature and has a complete nervous system. Since it does not have many defensive adaptations, it must use its brain to survive. The intelligence of these octopuses has undergone much research.
Chromatophores: Camouflage is an important method of defense used by the Pacific octopus. Chromatophores are the pigmentation sacs that allow octopuses to blend into their surroundings so flawlessly. Each chromatophore is made up of three different pigment sacs: yellow, red, and brown. The colored appearance of the octopus&rsquos skin is determined by small muscles. These muscles will pull a colored pigment sac to the surface to make that color is visible. When the muscle relaxes, the pigmentation from that sac goes away. The octopus uses its eyes to judge the color and texture of the camouflage it wants to wear. Working in conjugation with chromatophores are papillae. These small muscles under the skin are able to form the skin into peaks of varying heights. This allows the octopus to look rough or smooth, whichever blends in best with its current environment. Finally, males innately know which skin patterns to flash at females during in the courting process of reproduction.
Mouth: The mouth structure on the Pacific octopus contains many important feedingadaptations. A beak, which greatly resembles a parrot&rsquos, is sharp and used to bite and grasp prey. Inside the beak is a radula. This is a very rough tongue-like structure that contains ribbons of small teeth. The radula is used to scrape up their prey, often from within the prey's own shell! Salivary glands within the octopus&rsquos mouth region contain venom. The venom is used both to paralyze the prey and begin the octopus's digestion process. The venom is passed out through the salivary papillae. At the end of the salivary papillae is a set of drill-shaped teeth. These teeth are used to bore holes into the shells of the octopus&rsquos prey.
Siphon: The siphon can be found near the base of the octopus&rsquos mantle (the round-shaped head/body area.) The siphon is a primary player in the Pacific octopus's respiration. Water flows into the gill slit, goes past the gills, and is ejected out of the tube-shaped siphon.(A video of this can be seen here. With the use of quick muscular contractions, the octopus is able to rapidly shoot the water out of the siphon. This allows the octopus to zoom away, head-first, using jet propulsion. Under the octopus&rsquos digestive gland is the ink production gland. The ink is produced here, then stored in a larger sac, which is near the siphon. On a command, usually triggered by fear, the octopus releases the ink. Before being squirted out, the ink mixes with mucus. The ink solution is then expelled out of the siphon's opening. This causes the allows the octopus to use jet propulsion and flee in the opposite direction since the attacker is unable to see through the ink.
5 Answers 5
Octopuses, or at least the bigger examples of octopuses like the giant pacific octopus, are fairly big, and really smart. Those are usually the hallmarks of an animal with a fairly long life, but octopuses live fast and die young for one major reason: they devote their lives (or rather, the end of their lives,) to protecting a huge number of eggs, which then hatch and drift up to the surface, where they effectively live as plankton. Since parenting stops when the eggs hatch, it makes sense, from a reproductive fitness standpoint, for octomoms to work themselves literally to death protecting their eggs and ensuring that a high percentage of them hatch.
If young octopuses, rather than drifting free, were intensively cared for by their parents, who actively protected them and hunted to provide them with food, there would be strong evolutionary pressure for parents to remain fit and healthy, at least until their young were relatively mature.
Parental protection and feeding would also provide a strong motivator for females not to kill and eat their mates. While, for a single female, guarding her eggs until they hatch without eating means that a single large meal is more important than a second parent, if octopuses needed to actively hunt to ensure the survival of their young, there would be a strong pressure for cooperative parenting to evolve. For males, at least, this would lead to significantly longer life spans.
15 Incredible Octopus Photos and Facts
From the amount of hearts each octopus has to what music they enjoy our eight-limbed friends are some of the most interesting sea creatures that inhabit the oceans. With strong roots in mythology and even stronger roots within science investigations, the modern-day octopus is a species that we have yet to fully understand. These fascinating facts are just scratching the surface.
Octopuses are extremely colorful. Their cells contain something called chromatophores, which are basically little balloons that they can contract producing different shades of color. They can even produce multiple colors at the same time. Normally, they use this to hide from predators or communicate with each other. A study at the Marine Biological Laboratory in Woods Hole in Massachusetts revealed that some even change colors to match the beat of a song (in this case, Cypress Hill).
Don&rsquot confuse them for shy, but don&rsquot expect them to be the life of the party either. According to the Monterey Bay Aquarium in California, Octopuses are solitary creatures that don&rsquot travel in schools or associate with others outside of mating. They&rsquore usually hiding in caves unless they're searching for food or something along those lines.
According to Aquarium of the Bay in San Francisco, Octopuses only mate once in their lifetime and the females eat the males after. They do this because they stay with their eggs for as long as they can up until starvation. The males are usually distinguishable by their hectocotylus, which sits at the end of their arms and is how they&rsquore able to mate.
Fitting into basically any crevice or hole, octopuses are extremely agile. The only part of the body that is solid is their beak. Even with that, they&rsquore able to squeeze into the smallest spaces without injury or issue. They're even able to get themselves out of small jars and aquariums. Aquariums have to create special enclosures sometimes with astroturf (octopuses hate the texture) to keep them contained. Watch this video as proof.
When mating, octopuses can lay up to 100,000 eggs. According to the Aquarium of the Pacific in Long Beach, baby octopuses are only the size of a grain of rice when they hatch and after a year, only the size of a quarter. The many dangers they face after hatching are offset by the shear number of baby octopuses.
They&rsquore able to retain short-term information, escape from enclosures and learn by mimicking each other. Octopuses are probably one of the smartest sea creatures out there. According to Scientific American, &ldquoOctopuses and their relatives (cuttlefish and squid) represent an island of mental complexity in the sea of invertebrate animals.&rdquo One generalization is that they have nine brains, in reality they have nodes all throughout their bodies with one centralized brain.
In the right conditions, octopuses can grow up to 30 feet and weigh 600 pounds says the National Geographic. The Giant Pacific Octopus, which is commonly found on the northwestern coast of North America, can reach those heights if plenty of food and safety is available. The Giant Pacific Octopus can only live up to five years and most others up to two years.
It would be impossible to number the entire octopus species in the world. So far, we&rsquove been able to categorize 300 different species and barely made a dent. National Geographic reports that it&rsquos impossible to successfully categorize the entirety of its species and habits.
According to the Aquarium of the Bay in San Francisco, Octopuses generally have three hearts. They&rsquore Cephalopods, which means they have more than one heart that helps pump blood throughout their body. One of the hearts stops beating when they swim.
The Octopus Wolfi is the tiniest currently known. Measuring less than 1 inch and weighing less than 1 gram. It was discovered in 1913 and we still have a lot to learn from this tiny creature.
While only existing in salt water, the octopus can exist in both warm and cold water. The species that live in warmer water tends to be smaller with the cold water species being larger, which also effects its reproductive capabilities according to the Journal of Experimental Marine Biology and Ecology.
Octopuses can excrete a mixture of mucus and melanin as a way to protect itself from predators. This natural form of defense creates a blanket of darkness as seen here, which allows the octopus to quickly escape. The same melanin the octopus secretes is what humans have when darker pigments cause brown eyes and dark hair. It&rsquos also the same ink we use for pens.
According to the South African Journal of Marine Science, a bacterium causes the octopuses to eat their own arms and eventually crucial parts resulting in death. This bacteria incubates within their system for two weeks before causing the cannibalism. This study debunks the theory that they eat their arms out of boredom.
Already having their ink secretion defense system, octopuses are also able to wrestle and possibly enwrap you with their arms. Each arm can have up to 240 suction cups that are strong enough to shut a predator&rsquos mouth and possibly crush them. The Giant Pacific Octopus has enough strength to move more than 700 pounds!
Not many sea creatures use tools to help with protection or hunting, but the Coconut Octopus does. It even walks on two legs while carrying a shell! This medium-sized octopus uses the shell as a tool, but also has the ability to discriminate between old and new tools. If a newer or better tool is discovered, it will quickly leave the old behind.
11 Fun Facts That Prove Octopuses Are All Kinds Of Astonishing
Whether you know it or not, octopuses are incredible. They're some of the smartest creatures under the sea, they can change their appearance entirely, and some of them are pretty darn cute.
Below, 11 facts sure to convince you that octopuses are your new favorite animal.
1. Octopuses are widely considered to be the most intelligent of all invertebrates.
Scientists say octopuses are capable of learning from experience and maintaining short- and long-term memory. They've also been observed using tools in an intelligent manner -- such as coconuts for personal fortresses.
2. Octopuses have three hearts. And blue blood.
Two hearts serve to move blood past the gills, while the third pumps blood through the rest of the body.
3. Saying "octopi" is incorrect (unfortunately).
Though "octopi" is colloquially sound and very fun to say, the correct plural of octopus is octopuses.
4. They aren't called "tentacles," they're called ''arms."
Which, again, is way less fun. Tentacles are reserved for squid, cuttlefish and nautiluses. Octopuses have eight arms, zero tentacles.
5. And each arm has a mind of its own.
Some two-thirds of an octopus's neurons reside in its arms, meaning they can react to stimuli and function at a fairly high level on their own, even when severed from the body.
6. If Houdini were an animal, it's safe to say he would have been an octopus.
Since octopuses have no bones in their bodies, they can squeeze through the tiniest of cracks, making them masterful escape artists.
7. Octopuses are considered erotic in Japanese culture.
Octopuses have been incorporated into Japanese art for centuries, often in overtly sexual situations.
8. Their camouflage abilities are out of this world.
For ocean predators, octopuses are some of the most difficult prey to spot. Their skin changes color and pattern to blend in with their surroundings. Even when you find yourself looking directly at an octopus, chances are you won't realize it.
9. Partly because they can "see" with their skin.
Scientists recently found that octopus skin contains the same light-sensitive proteins present in octopus eyes, meaning an octopus's skin can sense and respond to light without information from the eyes or brain.
10. Rather than swimming, octopuses often walk along the seafloor.
Which is hilarious, but mostly useful -- when an octopus swims, the heart that pumps blood to its organs stops beating, so crawling is a more efficient, less exhausting alternative.
11. Some octopuses, like the dumbo octopus below, are unexpectedly adorable.
One species of octopus is so cute, it might be named Opisthoteuthis Adorabilis.
The main predators of a blanket octopus are large fishes and some types of whales. Since the male blanket octopus is very small they are vulnerable to attack from fishes than the females.
The female blanket octopuses unfurl their blankets in the event of a threat from a potential predator. This behavior is quite common in the animal kingdom. Generally, the bigger a prey appears, the more the predators will be suspicious and do not take a chance.
In the event where this deceptive defense doesn’t work, they can detach their blankets from their body, causing the predator to be tangled in it. The blanket of these species floating the ocean waters is a common sight in tropical & subtropical oceans (Though sighting living octopuses is difficult).
While they are not complete organs, the earthworm does have five pseudo-hearts, which are actually pairs of aortic arches that function similarly to a heart. These five arches, which each have only one chamber, are located near the earthworm's mouth. Earthworms breathe through their skin, relying on moisture to make their respiratory system function, and once oxygen has entered the body one of the five aortic arch pairs acts as the primary organ, pumping blood to the rest of the arches and oxygenated blood to the entire body using its nerve cells to regulate the heartbeat.
Earthworms have five hearts. Image credit: galitsin/Shutterstock
When the octopus is in a cold environment with low oxygen levels, hemocyanin carries oxygen more efficiently than hemoglobin, a metalloprotein in the red blood cells that also transports oxygen. The hemocyanin is also dissolved in the plasma rather than being carried within blood cells making the octopus’ blood look bluish.
About an hour after the octopus has died, the octopus’ tentacles still have the ability to move and react. The tentacles can continue to pick food and place it on its mouth.
6 Strangest Hearts in the Animal Kingdom
Hearts have become iconic symbols of Valentine's Day, but when it comes to hearts in the real world, one size doesn't fit all — particularly in the animal kingdom. The human heart beats about 72 times a minute, but in that same time, a hibernating groundhog's heart beats just five times and a hummingbird's heart reaches 1,260 beats per minute during flight. The human heart weighs about 0.6 pounds (0.3 kilograms), but a giraffe's weighs about 26 pounds (12 kg), since the organ needs to be powerful enough to pump blood up the animal's long neck. Here are some other creatures with strange hearts.
Mammals and birds have four-chambered hearts, but frogs have just three, with two atria and one ventricle, said Daniel Mulcahy, a research collaborator of vertebrate zoology who specializes in amphibians and reptiles at the Smithsonian Institution in Washington, D.C.
In general, the heart takes deoxygenated blood from the body, sends it to the lungs to get oxygen, and pumps it through the body to oxygenate the organs, he said. In humans, the four-chambered heart keeps oxygenated blood and deoxygenated blood in separate chambers. But in frogs, grooves called trabeculae keep the oxygenated blood separate from the deoxygenated blood in its one ventricle.
Frogs can get oxygen not only from their lungs, but also from their skin, Mulcahy said. The frog's heart takes advantage of this evolutionary quirk. As deoxygenated blood comes into the right atrium, it goes into the ventricle and out to the lungs and skin to get oxygen.
The oxygenated blood comes back to the heart through the left atrium, then into the ventricle and out to the major organs, Mulcahy said.
Mulcahy snapped this photo of a plains spadefoot toad (Spea bombifrons). "We have a saying," he said, that "not all frogs are toads, but all toads are frogs." (Photo credit: Daniel Mulcahy)
A whale of a heart
"It is the size of a small car and has been weighed at about 950 pounds [430 kg]," said James Mead, a curator emeritus of marine mammals in the department of vertebrate zoology at the Smithsonian Institution.The blue whale's heart is the largest of all the animals living today. Like other mammals, it has four chambers.
The organ is responsible for supplying blood to an animal the size of two school buses, said Nikki Vollmer, a National Oceanic and Atmospheric Administration (NOAA) and National Research Council postdoctoral fellow at the National Systematics Lab at the Smithsonian.
"The walls of the aorta, the main artery, can be as thick as an iPhone 6 Plus is long," Vollmer told Live Science. "That is a thick-walled blood vessel!" (Photo credit: © AMNH | D. Finnin)
Three hearts for cephalopods
There's nothing half-hearted about cephalopods. These tentacular marine creatures, including the octopus, squid and cuttlefish, have three hearts apiece.
Two brachial hearts on either side of the cephalopod's body oxygenate blood by pumping it through the blood vessels of the gills, and the systemic heart in the center of the body pumps oxygenated blood from the gills through the rest of the organism, said Michael Vecchione, director of the NOAA National Systematics Laboratory at the Smithsonian and a curator of cephalopods at the National Museum of Natural History.
Cephalopods are also literally blue-blooded because they have copper in their blood. Human blood is red because of the iron in hemoglobin. "Just like rust is red, the iron in our hemoglobin is red when it's oxygenated," Vecchione said. But in cephalopods, oxygenated blood turns blue. (Taonius borealis squid, Photo credit: Michael Vecchione)
Like other insects, the cockroach has an open circulatory system, meaning its blood doesn't fill blood vessels. Instead, the blood flows through a single structure with 12 to 13 chambers, said Don Moore III, a senior scientist at the Smithsonian's National Zoo.
The dorsal sinus, located on the top of the cockroach, helps to send oxygenated blood to each chamber of the heart. But the heart isn't there to move around oxygenated blood, Moore said.
"Roaches and other insects breathe through spiracles [surface openings] in the bodies instead of lungs, so the blood doesn&rsquot need to carry oxygen from one place to another," Moore said.
Instead, the blood, called hemolymph, carries nutrients and is white or yellow, he said. The heart doesn't beat by itself, either. Muscles in the cavity expand and contract to help the heart send hemolymph to the rest of the body.
The heart is often smaller in wingless cockroaches than in flying ones, Moore said. The cockroach's heart also beats at about the same rate as a human heart, he added. (Photo Credit: skynetphoto | Shutterstock.com)
The earthworm can't take heart, because it doesn't have one. Instead, the worm has five pseudohearts that wrap around its esophagus. These pseudohearts don't pump blood, but rather squeeze vessels to help circulate blood throughout the worm's body, Moore said.
It also doesn't have lungs, but absorbs oxygen through its moist skin.
"Air trapped in the soil, or aboveground after a rain when worms can stay moist, dissolves in the skin mucous, and the oxygen is drawn into the cells and blood system where it is pumped around the body," Moore said.
Earthworms have red blood that contains hemoglobin, the protein that carries oxygen, but unlike people they have an open circulatory system. "So the hemoglobin just kind of floats among the rest of the fluids," Moore said. (Photo credit: alexsvirid | Shutterstock.com)
If a zebrafish has a broken heart, it can simply regrow one. A study published in 2002 in the journal Science found that zebrafish can fully regenerate heart muscle just two months after 20 percent of their heart muscle is damaged.
Humans can regenerate their liver, and amphibians and some lizards can regenerate their tails, but the zebrafish's regenerative abilities make it a prime model to study heart growth, Moore said.
However, fish have unique hearts. They have one atrium and one ventricle, but they also have two structures that aren't seen in humans. The "sinus venosus" is a sac that sits before the atrium and the "bulbus arteriosus" is a tube located just after the ventricle.
As in other animals, the heart drives blood throughout the body. Deoxygenated blood enters the sinus venosus and flows into the atrium, Moore said. The atrium then pumps the blood into the ventricle.
The ventricle has thicker, more muscular walls, and pumps the blood into the bulbus arteriosus. The bulbus arteriosus regulates the pressure of the blood as it flows through the capillaries surrounding the fish&rsquos gills. It is in the gills where there is oxygen exchange across cell membranes and into the blood, Moore said.
But why does the fish need the bulbus arteriosus to regulate blood pressure?
The authors would like to thank our young reviewers, Erin and Joshua Rutland. Part of this work was made possible due to funding from the Anatomical Society with a Public Engagement and Outreach grant to Catrin titled Anatomy for ALL—Making Anatomy Accessible. We would also like to thank the British Science Association and University of Nottingham for awarding Catrin with a BSA Media Fellowship 2019.
1. ↑ See the paper 𠇋lood Vessels Under the Microscope” for information about blood [ 1 ].
 ↑ Machado, M., Mitchell, C., Franklin, J., Thorpe, A., and Rutland, C. S. 2020. Blood vessels under the microscope. Front. Young Minds 8:151. doi: 10.3389/frym.2019.00151
 ↑ Cleland, T., Stoskopf, M., and Schweitzer, M. 2011. Histological, chemical, and morphological reexamination of the “heart” of a small Late Cretaceous Thescelosaurus. Naturwissenschaften. 98, 203. doi: 10.1007/s00114-010-0760-1
 ↑ Jurgens, K. D., Fons, R., Peters, T., and Sender, S. 1996. Heart and respiratory rates and their significance for convective oxygen transport rates in the smallest mammal, the Etruscan shrew Suncus etruscus. J. Exp. Biol. 199:2579.
 ↑ Clark, N., Alibhai, A., and Rutland, C. S. 2018. Mending a broken heart—the genetics of heart disease. Front. Young Minds 6:19. doi: 10.3389/frym.2018.00019
 ↑ Simpson, S., Rutland, P., and Rutland, C. S. 2017. Genomic insights into cardiomyopathies: a comparative cross-species review. Vet. Sci. 4:19. doi: 10.3390/vetsci4010019