ns am a research study scientist at The college of Nottingham. My key area of research is cardiovascular biology and also I aid teach college students to become veterinary surgeons and scientists. When I am not working, I lug out a many community and also charity work and also love security time with my family, including my 2 grandchildren. I have actually three children. The youngest has actually just finished school and also the larger two have actually completed their degrees at university.

i am a Manchester-based science communicator and artist currently researching how art and games deserve to be offered as devices for scientific research outreach, as component of a M.Sc. At the university of Hull. I have operated in teamwork with researchers almost everywhere the world, creating interdisciplinary tasks that are supplied to communicate science come the public and to inspire civilization to get involved in STEM.

i am a teacher and also have taught young human being for end 20 years. I am additionally a skilled proofreader and also copy-editor and much more recently I have written my an initial children’s novel. I have two children, Joshua and also Erin, that love learning around animals and also science. In my spare time, I enjoy playing tennis to store my love fit and also healthy and my enthusiasm for the theater and acting keeps my love racing, specifically on opened night.


ns am an combine Professor that Anatomy and also Developmental genes at The university of Nottingham and also a 2019 British scientific research Association Media Fellow. Ns lead a group of research study scientists investigate why people and animals suffer from heart and also blood courage disorders, trying to find techniques come detect, prevent, and also cure. When I am no working, i love to travel around the world, visit museums, and also write scientific research fiction. My boyfriend Andrew and I go running to keep our hearts healthy. *catrin.rutland

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We all take ours hearts for granted: the fascinating organ inside everyone that beats continuously to store blood pumping v our bodies. Blood flow ensures that oxygen, nutrient from food, hormones, and waste commodities get come the exactly cells. The love is vital for maintaining humans and also most animals alive. Hearts room even an ext interesting when we research what they do, just how they look, exactly how they work, and the similarities and differences in the hearts of species across the planet. Is a giraffe heart comparable to a human heart? Which animal survives in spite of having no heart? can a heart yes, really beat over 1,500 time a minute? from dinosaurs to insects, human beings to dogs, this paper looks at what is really happening ~ above the inside, trying out the people of heart anatomy.

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How plenty of Hearts execute We Have?

You surely know that humans and giraffes have just one heart, as most animals do—but no all. Octopuses and also squids (animals called cephalopods) have actually three hearts. Two hearts pump blood to the gills to take it up oxygen, and the various other pumps blood around the body (Figure 1). Worms are also unusual, with 5 structures dubbed aortic arcs acting as an easy hearts. The hagfish, sometimes referred to as the slime eel, has actually one true heart plus three accessory pumps helping the blood come move. Simply when you assumed you had heard the all, some pets are heartless. Jellyfish, starfish, and also even corals manage very well without hearts. Starfish perform not also have blood, so this explains why no heart is required. Instead, they use tiny hair-like structures called cilia to press seawater with their bodies and also they extract oxygen native the water.

Figure 1 - The an easy structures of animal hearts.Bird and also mammal understanding have four chambers (two atria and also two ventricles). A frog, i beg your pardon is an amphibian, has actually a love with three chambers (one ventricle and also two atria), and also fish hearts have actually two chambers (one atrium and one ventricle). An octopus love system includes three hearts—one key heart (H1) pump blood to the body and also two other hearts (H2 and also H3) pumping blood to the gills. A, atrium; V, ventricle.

For Dr. Who fans, the fictional Time Lords have two hearts, however real humans an extremely rarely do. In incredibly unusual cases, world with the condition cardiomyopathy have actually a second heart attached top top their very own heart through doctors. The healthy and also damaged hearts occupational together come share the load. Also, pair that room born linked to each various other (conjoined twins) deserve to have 2 hearts naturally.

Mammal and also Bird Hearts

It is not just the number of hearts that can readjust between species. The basic structure that this critical organ deserve to be extremely various from one types to the next. Hearts greatly consist that muscle that contracts and also relaxes, leading to blood to move through blood ship to and also from the lungs and also around the body (Figure 2)1. Together mammals, us have four main components to the heart, a left and also a appropriate atrium and a left and also a right ventricle. This is dubbed a four-chambered heart. Other mammals and also birds all have four-chambered hearts. Other animal groups, such as reptiles, amphibians, fish, and insects, have hearts the look a tiny different (Figure 1).

Figure 2 - mind have adapted differently to finest suit every animal.(A) The giraffe has a very large left ventricle so the the heart muscle deserve to pump blood come the body and all the means up the lengthy neck come the head. The giraffe’s right ventricle is smaller, together it only pumps blood come the lungs. Microscope photos of the heart muscle that a chick (B) and a dog (C) are additionally shown. The chick is young and therefore only has actually one ventricle and also one atrium. Later, the chick heart will become four-chambered, v two atria and two ventricles.

Reptile and Dinosaur Hearts

Reptile hearts have three chambers, two atria and one ventricle (Figure 1). The exception is crocodilians, which have actually four-chambered hearts, as with mammals and also birds. However, over there is a feet in the crocodile room wall, so even if it is there room three or four heart chambers is up for debate. Civilization often wonder even if it is dinosaurs advanced from birds or reptiles. Detect a dinosaur heart is very rare because, unequal bone, the heart is a soft tissue, so that is not often preserved. One possibly fossilized heart showed up to present that dinosaurs had 4 heart chambers, much more like birds 보다 reptiles. Sadly, as this specimen was investigated further using more advanced clinical technology, it was discovered not to be dinosaur tissue, so us still execute not recognize enough around dinosaur hearts to predict which animals dinosaurs evolved from <2>.

Amphibian Hearts

Amphibians space an interesting group, as their hearts vary greatly. Life on land and also in water, countless get oxygen utilizing their lungs, but likewise take it increase via your skin. Many amphibians, consisting of frogs and toads, have three-chambered hearts, with two atria and one ventricle (Figure 1). However, lungless salamanders do not have a structure called a septum to division the atrium into two separate parts, therefore this pet has simply one atrium and one ventricle. Part lesser well-known amphibians it seems to be ~ to have actually a septum in in between their ventricles, so perhaps ancient amphibians had four-chambered hearts, like mammals and birds.

Fish and Insect Hearts

Fish hearts have just two chambers, one atrium and a ventricle (Figure 1). Insects frequently have simply a tube the pumps hemolymph (the surname for the insect tantamount of blood) freely about the entire body, v a ship to help it move. Cockroaches, however, have actually 13 love chambers!

How large is her Heart?

It goes there is no saying the heart size varies in different animals. After ~ all, a whale could not endure with a mouse-sized heart. One adult person heart weighs around 0.6 lbs. If you make a fist, that is around the size of your heart. The giraffe love is a hefty 26 lbs, yet the blue whale yes, really tips the scale at 400 lbs. The world’s smallest heart belongs come the fairyfly. This tiny pet is simply 0.2 mm long, and also a microscope is essential to watch its heart.

Hearts room normally about 0.6% of one animal’s human body mass. Dogs and wolves have actually relatively huge hearts in comparison with their weight, at 0.8%. Meanwhile, the cat heart is just 0.35% the a cat’s human body weight. Hopefully, relative heart size and also the quantity of love animals feel are not related. If lock were, the world’s smallest mammal, the Etruscan shrew, would have a the majority of love to give! The mouse-like shrew weighs a tiny 2 g and also is around 4 cm long, yet its heart renders up 1.2% that its body load <3>. Scientists also found that the shrew heart deserve to shrink in cold weather. This shrinkage helps shrews make it through harsh climates, by to reduce the amount of food the needs. This little mammal eats twice its body weight in food every day, for this reason hibernation is no an option. Castle rarely even sleep.

Swift and Sluggish heart Rates

The method animals’ hearts job-related varies in between species, too. The heart rate, measure up in beats per minute (bpm), varies in different species. Generally, larger animals have slow heart rates. A big slug has actually a heart rate of around 55 bpm, while smaller slug species are in the 90s. Many whales have heart rates of 10–30 bpm, giraffes space 40–90, and cats are approximately 150. In also smaller animals, the number increases: an adult chicken has actually a heart rate of 259 bpm, a chick is 400 (Video 1), and the hamster love beats far at 450 bpm. The tiny Etruscan shrew clocks 835 bpm, more than 12 times greater than a person. The highest possible recorded shrew price was 1,511 bpm, a human being record for a warm-blooded pet <3>.

People have heart prices of around 60–100 bpm, but children often have slightly higher rates. At 1 month old, 70–190 is reasonably normal, 80–120 because that 3–4-years-olds, and 60–100 by the moment a child is 10 years old. A farming baby inside its mom starts at 80 bpm in week 5, 155–195 in ~ 9 weeks old, and also around 130 just before it is born. Interestingly, the human heart starts together a pipe in the 19–20-days-old embryo, rather prefer a fish, however gradually rotates, develops, and separates into 4 chambers over the next 6 weeks.

Exercise, Temperature and also Hibernation All readjust Heart Rate

Heart rate transforms in most exercising animals. Running giraffes can reach 170 bpm and humans deserve to hit 220, yet ideally it have to be a little less. A crocodile heart price at 10° C is 1–8 bpm, in ~ 28° C it hits 24–40, and also once the reaches over 40° C, the heart can become damaged. Young swifts (birds) lower their love rates as soon as in the nest, to stop starvation. Hibernating animals can additionally lower your heart rates. Grizzly bears typically clock 84 bpm, which lowers come 19 bpm throughout hibernation; a human being heart would usually stop working if it went the low. Emotions, such together fear, love, and also excitement, and hormone levels, sickness, oxygen levels, and also other components both inside and outside that the body can readjust the love rate.

Mending a damaged Heart

In ours previous Frontiers for Young Minds document “Mending a damaged Heart,” us looked at addressing failing hearts <4, 5>. The zebrafish has a an extremely important ability: it can regenerate (regrow), so if it gets hurt or the heart has a problem, it can frequently repair itself. Human bodies are fantastic, and they continuously try to replace heart cells and also repair love tissue, yet the zebrafish is a real experienced at repair a broken heart.


In this article, us looked at some of the similarities and also differences between the mind of various species. Mammals and birds have very similar hearts as result of evolution, when reptiles, fish, insects, and other pets evolved understanding that room slightly in different way from those the mammals. The atmosphere both inside and outside that each animal helps manage the heart’s structure and function, but lifestyle choices, such together exercise and also food, have the right to have huge impacts on her heart’s health. Her friends’ mind are much more similar to yours 보다 to a giraffe’s because that example, and also even more similar 보다 to a frog or spider heart, yet every person’s heart is unique. Her heart is constantly adapting to the instances you space in, reacting to food, exercise, emotions, and illness. Unlike a squid, friend only have actually one heart, and also it will beat approximately 2.21 billion times in her life, so the is worth keeping it healthy.


Cephalopods: pets without backbones, including squids, octopi, and also nautiluses. Cephalopods have actually symmetrical bodies, prominent heads, and tentacles.

Atrium: The upper chamber or chambers of the heart. The plural is atria: because that example, you deserve to have one atrium or 2 atria.

Ventricle: The reduced chamber or chambers that the heart.

Amphibian: pets with backbones that need water or wet settings to survive. Amphibians include toads, frogs, salamanders, and also caecilians (amphibians without foot or limbs).

Hemolymph: Fluid, comparable to blood, that some an easy animals have to move nutrients and also oxygen around their bodies.

Heart Rate: The number of times every minute that a love beats.

Video 1: early on, once a chick is cultivation in one egg, the heart can be seen on the external of the body. Over time, the heart will relocate inside the body. This video shows a chick’s love beating once it is just a couple of days old. The love is tho a tube containing 2 chambers, a ventricle and an atrium, but as it grow it will eventually have four chambers. You have the right to see the blood pumping v the heart chambers.

Conflict the Interest

The authors declare that the study was performed in the lack of any kind of commercial or financial relationship that could be construed as a potential conflict of interest.


The writer would like to say thanks to our young reviewers, Erin and Joshua Rutland. Component of this occupational was made feasible due to resources from the Anatomical society with a windy Engagement and Outreach provide to Catrin titled Anatomy for ALL—Making Anatomy Accessible. Us would likewise like to thank the British scientific research Association and also University that Nottingham for awarding Catrin with a BSA Media Fellowship 2019.


1. see the record “Blood ship Under the Microscope” because that information about blood <1>.

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<1> Machado, M., Mitchell, C., Franklin, J., Thorpe, A., and also Rutland, C. S. 2020. Blood vessels under the microscope. Front. Young minds 8:151. Doi: 10.3389/frym.2019.00151

<2> Cleland, T., Stoskopf, M., and Schweitzer, M. 2011. Histological, chemical, and morphological reexamination that the “heart” of a tiny Late Cretaceous Thescelosaurus. Naturwissenschaften. 98, 203–211. Doi: 10.1007/s00114-010-0760-1

<3> Jurgens, K. D., Fons, R., Peters, T., and also Sender, S. 1996. Heart and respiratory rates and their significance for convective oxygen transport rates in the the smallest mammal, the Etruscan shrew Suncus etruscus. J. Exp. Biol. 199:2579–84.

<4> Clark, N., Alibhai, A., and also Rutland, C. S. 2018. Mending a damaged heart—the genes of heart disease. Front. Young minds 6:19. Doi: 10.3389/frym.2018.00019

<5> Simpson, S., Rutland, P., and also Rutland, C. S. 2017. Genomic insights right into cardiomyopathies: a compare cross-species review. Vet. Sci. 4:19. Doi: 10.3390/vetsci4010019