Sharks tend to have very large livers that help them float and survive for extended periods without food. A shark’s liver is comprised mainly of fats and lipids. Depending on type, it can weigh up to 25% of the shark’s total weight and take up almost 90% of its internal body cavity.
More about sharks:
- Several species of sharks are sensitive to magnetic fields. Scientists are working on ways to harness magnets to repel sharks from beaches. Scientists also theorize that a shark’s sensitivity to the Earth’s magnetic field may help it navigate the oceans.
- Most shark attacks have happened in water less than six feet deep.
- The shark skeleton is made of cartilage, not bone. In fact, there is not a single bone in a shark’s body.
Frequently Asked Questions
How large is the liver of a shark compared to its body size?
The liver of a shark is quite large relative to its body size, accounting for up to 25% of its total body mass. This significant proportion is due to the liver's role in buoyancy, as it contains squalene, a low-density compound that helps sharks maintain their position in the water column without expending much energy.
Does the size of a shark's liver vary among different species?
Yes, the size of a shark's liver can vary widely among species. For example, the liver of a basking shark can be enormous, making up nearly one-third of its body weight, while smaller shark species have proportionately smaller livers. The liver size is adapted to the lifestyle and habitat of the shark species.
What is the function of a shark's liver?
A shark's liver has multiple functions, including digestion, storage of energy-rich oils and fats, and, importantly, buoyancy control. The liver secretes bile to aid in digestion and stores nutrients, but its role in producing squalene is crucial for helping sharks to float by counteracting their naturally dense bodies.
How does the liver aid in a shark's buoyancy?
The liver aids in a shark's buoyancy through the production and storage of squalene, a light hydrocarbon that is less dense than water. This substance fills the liver and provides lift, allowing sharks to glide effortlessly through the ocean without sinking, despite lacking a swim bladder that other fish use for buoyancy.
Can the size of a shark's liver affect its survival?
The size of a shark's liver can indeed affect its survival. A larger liver with ample squalene allows for better buoyancy control, which is critical for hunting and energy conservation. Conversely, a compromised liver, whether by disease or injury, can hinder a shark's ability to maintain its position in the water and survive in its environment.
Is the liver of a shark targeted by fisheries, and why?
Shark livers are targeted by some fisheries because they are a source of squalene, which is used in cosmetics and medicinal products. Additionally, shark liver oil, known as "shark liver oil," has been harvested for its supposed health benefits, although this practice has raised concerns about sustainability and shark conservation.
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Discussion Comments
@browncoat - II'm not a big fan of fishing for sharks, because so many of them are endangered now. But I'd definitely rather that people were eating the whole shark (although not the liver) rather than just the fin. Often people will just slice off the shark's fin and leave it to die, because they get more money for that one part.
And that's not including the people who hunt sharks because they think they are dangerous. There have actually been very few shark attacks recorded and most of the time sharks are harmless to people.
They are such a valuable part of the ecosystem, I would hate for them to become extinct just because we overreact to their presence. It's something we would deeply regret in the future.
@Fa5t3r - Well, I don't know about the liver, but I do know that people eat shark meat probably more often than they realize. It often gets sold in shops as "flake" or some other benign label and will get put into fish fingers and other processed fish products as well.
I don't know why it is so much cheaper than normal kinds of fish, but maybe it's because it doesn't taste as nice and it would otherwise just be a byproduct of a normal catch.
But I imagine they wouldn't sell the liver if it really was that dangerous. I think they do mercury testing to make sure no one is going to get hurt from fish.
I've heard that you've got to be careful not to eat shark liver, because it can be extremely high in mercury and other dangerous substances. Sharks are the top of the food chain in the ocean, of course, so they end up concentrating all of the pollutants from the fish that they eat in their tissues.
And I imagine that the liver is one of the most toxic parts of the body, because it has so much fat in it and fat tends to store chemicals.
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