Great whites: even hungrier than you thought

great white shark

Perhaps not surprising to any who suffers from galeophobia, researchers now believe great white sharks eat far more than previously thought.

An Australian study published this week found that great white sharks, the world’s largest predatory fish, eat three to four times more food than once believed.

That’s considerably more than the findings of a 1982 US research team. Then, it was estimated that a meal of approximately 66 pounds of mammal blubber could sustain a 2,160-pound shark for approximately six weeks, according to the website Real Clear Science.

However, University of Tasmania researchers reported this week that 66 pounds of blubber was only enough to glut a great white for about two weeks, according to a study published in Scientific Reports on the website.

Researchers tagged a dozen great white sharks off the coast of the Neptune Islands off South Australia and calculated their metabolic rate derived from swimming speeds, according to Agence France-Presse.

They then worked out how much energy the sharks burned and how much food they required.

The amount of energy required by great white sharks was equivalent to eating a seal pup every three days, according to senior research scientist Jayson Semmens, the lead author on the study.

“Based on the past data, that rate would have only been one pup every 173 hours,” according to Real Clear Science. “So this means that cute, cuddly, furry seal pups may be getting horrifically consumed much more often.”

The Neptune Islands are off the coast of South Australia, shown in red.

The Neptune Islands are off the coast of South Australia, shown in red.

Real Clear Science based its calculations on the needs of a 2,160-pound great white.

“And keep in mind that some great white sharks can grow to be nearly 5,000 pounds!” it added. They probably sport a more voracious appetite …”

Semmens told ABC television that the US researchers in 1982 were working with a single shark, and may well have inadvertently chosen a great white that “wasn’t working very hard” at the time of their study.

The results of that limited inquiry perpetuated assumptions that large sharks could survive long periods without eating.

By comparison, the great whites at the seal colony off the Australian coast were working hard to and reaching high speeds to catch seals, Semmens added.

“Their metabolic rate or the engine that runs them is much faster than what we had assumed,” he said. “These animals are probably going to be feeding you know every few days, rather than multiple weeks.”

The study also emphasized the great white’s role in the ocean ecosystem, according to Agence France-Presse.

“We don’t have a good handle on the population sizes of white sharks. We know that sharks in general are under pressure around the world from overfishing,” Semmens said. “They’re quite vulnerable because of their life history, they’re long-lived, they reproduce late in their life and they produce a small number of offspring.”

Semmens said the unintended consequences of overfishing great whites are far more important than realized.

“They’re keeping under control a lot more animals than we thought,” he said.

20 thoughts on “Great whites: even hungrier than you thought

  1. I remember watching a documentary years back that said a seal pup will last a white a month, I knew this to be incorrect, higher metabolism require more food more often, they even thought they only fed on seals I knew this had to be wrong, after all before reaching a certain size they were fish eaters and I doubt they forgot how to hunt fish, I say they eat when hungry no more no less. I saw another show that tested how much a white can eat in one day and they fed a white tuna fish and it ate like 400 plus pounds before stopping. awesome fish.

  2. I can’t click Like, I did NOT need to know that they were even more likely to want to eat me than before….
    Yes, I’m galeophobic and you’re not helping! 😉

    • I used to surf on occasion off California’s central coast and, in between sets of waves, when I would be laying on my board waiting, my mind would wander off. I would get to thinking about what’s below, especially since the water was dark and great whites were known to inhabit that area. It never kept me out of the water, but it did give me an appreciation of man’s real place in nature.

      Of course, the story that always gets my girls laughing uproariously is when I tell them about the time I was paddling out and saw a (small) jellyfish in front of me. I immediately stopped and started flailing around, trying to get around it. Finally, after inadvertently slipping off my board and essentially exhausting myself, I realized that the waves would have taken it right past me if I’d just stayed on my board and remained calm.

      • See, now my paranoid mind is just thinking it was lucky your jellyfish flailings didn’t attract some unwanted and toothy attention!
        I am not sure why I have such a thing about sharks, I have never had a bad experience with one, I can only put it down to being an early and avid reader and picking up Jaws when I was FAR too young…

  3. Bah! This gives me goosebumps. However I’m “braver” than you, Metan. I hit “like”. 😉 It’s reading stories like that of the USS Juneau and USS Indianapolis that really give me galeophobia.

  4. Greatstory. A humble hero is even better to hear about. You know, Metan, if this scares you you’re going to love one of my upcoming posts about the 1916 New Jersey shark attacks. Have a spare “doona” for this coward to hide under?

    • I am not sure I will be able to Like that one 🙂 Is that about the shark that made its way up the river and wreaked havoc? *shudder* I saw a movie about that, it did NOTHING to help me get over my shark ‘thing’!

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