Greenland Sharks' Diet: How Much Food Should These Aquatic Mammals Eat for Daily Survival?

From the University of Windsor in Canada, Eric Ste-Marie is strongly focusing his work on what Greenland sharks are eating and how much they need to eat daily to survive, which is scientifically called their "metabolic rate."

As indicated in a Forbes report, when an individual might live up to 500 years, time moves a little differently for him. A single day might feel like a second; one week might feel like one day. Therefore, when time is this abstract thing, one may wonder, "how is mealtime spaced out?"

Such a question for Greenland sharks, with the scientific name, Somniosus microcephalus, were the longest-living vertebrates in the world, not to mention, one of the longest-living animals worldwide.

Essentially, a sleeper shark that can reach 23 feet long, they are mainly found in the cold-water environments of the North Atlantic and Arctic Oceans.

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(Photo: Wikimedia Commons/Hemming1952)
Close-up image of a Greenland shark taken at the floe edge of the Admiralty Inlet, Nunavut.

Greenland Sharks, Slow-Moving Carnivores

There's little knowledge about these marine creatures, although these slow-moving carnivores are frequently made up of many different aquatic animals like smaller sharks, fish, and seals.

When it comes to the amount of food these sharks eat, the new study published in the Journal of Experimental Biology, specified that it turns out to be "not a lot."

Ste-Marie and colleagues reported the stunning Greenland sharks' stunning metabolic rate. They also found that these gigantic predators only need about 61 to a little over 190 grams of fish or mammal prey each day.

The data is collected from 30 Greenland sharks that the research team tagged, sampled, and fitted with a five-year-old biologger kit. Such kits recorded the body movements and body temperature of the sharks and the water temper temperature.

Daily Calorie Requirement

Utilizing the data from the tags, the study authors could compute the Greenland sharks' daily calorie requirements. For instance, a 500-pound individual would require between two and 6.5 ounces of fish or marine animal prey to survive.

In their report, the team stated that as a "lethargic polar species," these FMR or field metabolic rate estimates, as well as the corresponding prey consumption estimates, have suggested that Greenland sharks, which are detailed in a National Geographic report, require "very little energy" to sustain themselves under normal conditions.

As explained by Ste-Marie, these animals' sluggish metabolic rate may be key in understanding how these sharks have extraordinarily long lifespans.

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This number is substantially lower than figures from other sharks, as previous research has revealed that a great white shark weighing 2,000 pounds would need to devour 66 pounds of fat every 11 days to survive. Some scientists have claimed that great white sharks are believed to live up to roughly 75 years.

Importance of Knowing the Greenland Sharks' Nutritional Needs

By more thoroughly examining the Greenland sharks' slow lifestyle, Ste-Marie and his team have presented the first characterization of the energetics and consumer role of this susceptible and understudied shark species in the wild. The team explained that this is important given the growing pressures from climate change and "expanding commercial fisheries in the Arctic."

By knowing these animals' nutritional needs, scientists can start predicting how the former may fare when there comes a shortage of food due to climate change since the Arctic is warming the global annual average thrice, driving a lot of changes underway in the Arctic.

Related information about the Greenland sharks is shown on Deep Marine Scenes' YouTube video below: