Last updated on December 8th, 2023 at 10:35 am
What makes multiple hearts so exceptional is their rarity. Most animals function seamlessly with just one heart, making those with multiple hearts truly extraordinary. In its wisdom, nature has bestowed these creatures the ability to adapt and thrive, demonstrating the power of additional hearts in enhancing their biological functions.
Examples abound, from the intelligent octopus to the elusive cuttlefish, humble earthworm, and enigmatic hagfish. Each creature has evolved separate hearts, each assigned specific duties within their circulatory systems. In this article, we embark on a journey to explore the wonders of five incredible beings with multiple hearts.
|Number of Hearts
5 Stunning Animals With Multiple Hearts
- Scientific name: Octopoda
- Number of hearts: 3
- Animals Type: Mollusk
In the underwater realm, octopuses stand out not just for their mesmerizing colors and shape-shifting abilities but for a remarkable biological feature—three hearts. Unlike most creatures with one or two hearts, octopuses have evolved a trio of pumping organs, each with a specific role.
Octopuses, found in diverse oceanic environments, showcase adaptability in almost any depth—from the Abyss to small tidal pools along the shore. Beyond their cardiovascular marvel, these cephalopods exhibit an extraordinary ability to change color and shape, making them masters of disguise. Some evidence even suggests their intelligence, hinting at potential tool usage.
Interestingly, octopuses display a fascinating energy-saving strategy. While swimming, the energy-demanding systemic heart temporarily shuts down, leaving the branchial hearts to sustain oxygen flow to the gills. This sheds light on why octopuses, despite their oceanic prowess, tend to conserve energy by crawling or floating rather than swimming extensively.
Image Source iStock
- Scientific name: Decapodiformes
- Number of hearts: 3
- Animals Type: Mollusk
In the deep expanses of the ocean, squids share a fascinating trait with their cephalopod cousins—the possession of three hearts. Much like octopuses, squids have a systemic heart propelling blood through their bodies, accompanied by two branchial hearts dedicated to oxygenating their gills.
Nestled within the mantle cavity, a seawater-filled sac, all three hearts collaborate to orchestrate the squid’s circulatory dance. The systemic heart, with a lower ventricle and two atria, mirrors the design seen in octopuses. The copper-rich hemocyanin in squid blood, appearing deep blue in low-oxygen environments, attests to their adaptability.
As blood returns to the branchial hearts, squids utilize specialized openings, nephridial appendages, for the efficient excretion of urine, carbon dioxide, and waste products. This closed circuit within the mantle cavity ensures seamless management of essential organ functions, from respiration to waste elimination.
Read Also: Animals With Small Eyes
- Scientific name: Myxini
- Number of hearts: 4
- Animals Type: Fish
In the eccentric realm of animals with multiple hearts, the hagfish claims its spot as a truly bizarre creature. Resembling an eel, this slimy fish defies conventional anatomy, boasting four hearts—a feature that sets it apart even among its cephalopod counterparts.
Living at the ocean floor’s depths, the hagfish navigates a challenging environment where oxygen is scarce. To adapt, one of its hearts, the branchial heart, pumps blood throughout its body, while the remaining three hearts act as auxiliary pumps. Remarkably, hagfish hearts showcase an extraordinary ability to beat for an astounding 36 hours without oxygen—a feat unparalleled in the animal kingdom.
Found in both the Atlantic and Pacific oceans, hagfish thrive with few natural predators. Their defense mechanism involves producing copious amounts of slime, which not only deters predators but can also impede the breathing of other fish by clogging their gills. This ingenious adaptation ensures the hagfish’s survival in its oxygen-poor habitat.
- Scientific Name: Sepiida
- Number of hearts: 3
- Animals Type: Mollusk
In the enchanting world of cephalopods, cuttlefish emerge as the unsung heroes with a unique twist—the possession of three hearts. Unlike most mollusks, cuttlefish boast a closed circulatory system, aligning them with their cephalopod relatives, squids, and octopuses.
A curious adaptation unfolds—the need for rapid blood flow. Hemocyanin, carrying less oxygen than hemoglobin, compels cuttlefish to maintain a brisk circulatory pace to ensure adequate oxygenation. This distinctive trait sets them apart in the underwater ballet of life.
While sharing three hearts with their cephalopod cousins, cuttlefish possess their unique intelligence. Widely found across the globe, with the largest species calling Australia home, cuttlefish showcase a remarkable level of cognitive prowess. Some even argue that among invertebrates, cuttlefish might claim the title of the most intelligent—an intriguing facet of these masters of the ocean’s heart-filled depths.
- Scientific name: Opisothpora
- Number of hearts: 5
- Animals Type: Roundworm (invertebrate)
In the lineup of animals with multiple hearts, the unassuming earthworm takes a different approach—no heart at all. Instead, it sports a heart-like system known as an aortic arch, creating a closed circulatory marvel within its small, slimy frame.
Contrary to the typical heart structure, earthworms rely on a sophisticated aortic arch composed of five blood vessels. Positioned strategically, the dorsal vessel propels blood forward, while the ventral, subneural, and two lateroneural vessels ensure the backward flow, orchestrating a unique circulatory dance.
While technically lacking a true heart, earthworms possess five pseudo-hearts—primitive organs resembling aortic arch pairs. Nestled near their mouths, these arches pump blood and oxygenate the earthworm’s body, showcasing an unconventional yet efficient approach to circulation.
Read Also: Animals With Big Foreheads
Beyond the Singular Beat: Nature’s Intricate Hearts
Horses, known for their strength and elegance, harbor a remarkable feature resembling an additional heart—the frog in their hooves. Serving as both a shock absorber and an ingenious blood pump, the frog operates like a triangular cushion. When the horse makes contact with the ground, the frog, driven by the horse’s weight and kinetic energy, actively pumps blood up the legs and back toward the heart. This dual functionality showcases the intricacies of nature’s design in optimizing the circulatory system for these majestic creatures.
In the insect realm, the cockroach stands out with a cardiovascular system that, while not technically boasting multiple hearts, is nonetheless extraordinary. Sporting an impressive 13 heart chambers, the cockroach’s circulatory design is a marvel of nature. Oxygenated blood flows through tubular chambers via tiny openings called Ostia, revealing the insect’s adaptability and resilience. Although not meet the conventional definition of multiple hearts, the cockroach’s intricate chambers exemplify evolutionary adaptations that contribute to its survival prowess.
In the realm of medical science, humans, typically born with a singular heart, can, under certain circumstances, live with what can be considered multiple hearts. Severe heart diseases like cardiomyopathy may necessitate a heterotopic or “piggyback” heart transplant. In this groundbreaking procedure, surgeons graft a second heart onto the patient’s existing heart to compensate for reduced functionality. While not an original heart, this surgical innovation challenges the notion that humans cannot have two hearts, showcasing the resilience of medical advancements in cardiac care.
So, let us continue to marvel at the wonders around us, appreciating the myriad ways life has evolved and adapted to the diverse landscapes of our planet. In the grand symphony of existence, each heartbeat, whether three, four, or five, contributes to the harmonious rhythm of life on Earth.
The octopus, with its three hearts orchestrating a ballet of circulatory marvels, captivates the depths with intelligence and grace. Squids, the ocean’s triple-hearted giants, navigate the unseen world with prowess, their colossal size and adaptability setting them apart. Cuttlefish, the masters of three hearts, add a splash of cognitive brilliance to the oceanic ensemble, proving that intelligence knows no bounds in the aquatic realm.
1. Why Do Some Animals Have Multiple Hearts?
Evolutionary forces have shaped organisms in ways that optimize their survival. The presence of multiple hearts in certain animals is a testament to the advantages it confers. From enhanced circulatory efficiency to improved oxygenation, these creatures have evolved to thrive in their respective environments.
2. How Do Multiple Hearts Function?
The anatomy and functionality of these extra hearts are a marvel in themselves. While humans rely on a single pump, some animals distribute the workload across multiple hearts, resulting in remarkable cardiovascular efficiency. Understanding these mechanisms provides insight into the diversity of life on Earth.
READ OUR OTHER ANIMAL BLOGS BELOW: