By Jim Knox
In 2022, Connecticut’s Beardsley Zoo celebrated its centennial. As part of our year-long celebration, our Education Team was charged with designing a summer show that captured the spirit of the zoo’s 100-year history of conservation and education. To capture some of that spirit, we decided to feature animals that embodied the theme of “100”. Among these animals were those remarkable creatures which pushed north of the century mark, surpassing a double-digit lifetime.
Even for folks who work among wild creatures, our jaws dropped in amazement upon researching the newest longevity record holders in the animal kingdom. From 114-year-old Blue and Gold, Macaws, to 121-year-old Johnstone’s Crocodiles, to 142-year-old Galapagos Tortoises, we were truly impressed but there was one that topped them all, and its record was no small feat. This beast wallops the competition, and at 272 years of age, it is a true marvel of nature!
Any creature that can reach the ripe old age of 272, has my respect, but this Polar beast is a creature of superlatives. At lengths reaching 24 feet and weights exceeding 3,100 pounds the Greenland Shark, Somniosus microcephalus, is one of the planet’s largest sharks. Also known as the Grey Shark, Gurry Shark, and Eqalussuaq, the Greenland Shark is a species whose natural history remains as elusive as the beast itself.
Living in the frigid waters of the North Atlantic and Arctic Oceans—and the only shark species that can withstand the extreme cold of the Arctic Ocean year ‘round, the Greenland Shark is as hardy as they come. Coupling that hardiness with the ability to range deeper than 7,200 feet, these sharks push past the limits of most species.
A robustly built cream-gray or blackish brown shark with a small, rounded head and very small pectoral and dorsal fins, the Greenland Shark is instantly recognizable. Unlike other cold-water sharks such as Great White Sharks which harness the heat generated by their swimming muscles to warm their bodies, Greenland Sharks and their close cousins, Pacific Sleeper Sharks, utilize a unique method to keep their bodies warmer than the icy waters around them by producing and storing high concentrations of a chemical compound known as urea to protect their bodies from extreme cold. In recent years this cold-water hardiness has been recorded well beyond the shark’s known North Atlantic and Arctic Ocean realm. In recent years, the shark’s known range has been expanded to include Canada’s Saint Lawrence River, and even the waters of the Gulf of Mexico, Cuba, and Belize at depths greater than 4,000 feet!
Known as an ambush predator, these sharks will lie in wait for passing prey or approach extremely slowly before rapidly opening their buccal cavity, creating instant suction around the prey, pulling it into the shark’s mouth. Common prey species such Capelin, Arctic Char, smaller sharks, skates, eels, Wolfish and flounder are often swallowed whole. Larger prey such as seals, Polar Bears, reindeer, and moose are believed to be scavenged piecemeal.
As a result of an unusual and poorly understood interspecies relationship, the shark may benefit from infestation by a small copepod, Ommatokoita elongata. These small creatures attach themselves to the shark’s eyes, damaging the fish’s eyes in multiple ways. This may lead to near blindness for the shark, yet it is believed by biologists that the bioluminescent qualities of the copepod aid the shark by attracting prey and perhaps even illuminating the inky black water around it, to aid in navigation. With the Greenland Shark’s exceptional hearing and sense of smell, such seeming parasitism does not diminish their predatory capability or their life expectancy.
This is where the Greenland Shark commands the attention of even the most grizzled biologists. While incredibly slow growth rates of ¼-½ inch per year hinted at impressive longevity of more than 100 years, it wasn’t until the advent of radiocarbon dating technology to date the crystals within the lenses of the shark’s eyes that an accurate range of longevity emerged. We now know that these amazing creatures reach reproductive maturity at approximately 150 years of age and may live as long as an astounding 512 years!
In the Greenland Shark we have a creature with such much to impart. I would say any beast that can survive more than half a millennium is worthy of both our attention and our emulation. So, what can we humans learn from these ancient giants? Utilizing great patience coupled with quick action, we can frequently achieve objectives that would otherwise prove elusive. Additionally, by utilizing our own unique skills or abilities to adapt to a seemingly hostile environment, we can venture into realms considered foreign…if not outright impossible.
Jim Knox serves as the Curator of Education for Connecticut’s Beardsley Zoo and as a Science Adviser for The Bruce Museum. A Member of The Explorers Club, Jim enjoys sharing his passion for wildlife conservation with audiences in Connecticut and beyond.
