Sharks are actually a species that is very afraid of humans, and scientists still do not know much about these famous ocean predators. For example, until recently, sharks were thought to be solitary creatures that searched for food in the sea, but it has been discovered that some species exhibit quite high social bonds.
Another mystery is how these destructive machines digest food. Although scientists have made 2D sketches of the digestive systems of sharks based on dissections of captured specimens, there is a limit to what can be discovered in this way.
Sharks remain a creature with many mysteries that humans have yet to explore.
“The intestines are very complex, with many layers stacked on top of each other; dissection destroys the context and connectivity of the tissue. It would be like trying to understand what is reported in a newspaper by cutting a rolled-up copy with scissors. The story would no longer hold together,” said Professor Adam Summers from the Friday Harbor Laboratories at the University of Washington.
Summers is a co-author of a new study that created the first 3D scan of a shark’s intestines. It turns out that it has a structure resembling a peculiar spiral. Upon closer inspection, it even has strange points that look like one-way valves designed by inventor Nikola Tesla in 1920.
3D model of a shark’s intestines.
“It is time for some modern technology to be used to examine these truly wonderful spiral intestines of sharks. We have developed a new method to digitally scan these tissues, and now we can examine such soft tissues in exquisite detail without having to cut into them,” shared Samantha Leigh, the lead author of the study.
Summers added: “CT scanning is one of the only ways to understand the shape of a shark’s intestines in three-dimensional space. Researchers have scanned the intestines of nearly thirty different species of sharks.”
In the past, it was believed that sharks could go for long periods without eating, several days or even weeks, between large meals. The 3D scan results indicate that food passes slowly through the intestines, allowing the shark’s digestive system time to fully extract its nutritional value. Researchers hypothesize that such a slow digestion process may also require less energy.
However, this slow digestion process makes food more prone to reflux, meaning that the momentum of digested food moving through the intestines must be kept to a minimum. This may be why sharks have evolved their intestines to resemble something very similar to a Tesla valve.
Above is a Tesla valve, below is a shark’s intestines.
“The microfluidic regulating valve,” or what the world now calls “Tesla valve“, is a type of one-way valve that has no moving parts. Its unique operation is based on fluid dynamics and has only recently been fully appreciated. Essentially, a series of teardrop-shaped loops arranged along the length of the valve allows water to flow easily in one direction but prevents it from flowing in other directions. Modern experiments show that at low flow rates, water can pass through the valve in both directions, but at high flow rates, this design proves effective.
Summers believes that the 3D scanning process is just the beginning.
This scientist suggests that “most shark species and much of their physiology are completely unknown,” adding that “every historical natural observation, internal visualization, and anatomical investigation reveals things we could not have guessed.”
To achieve this goal, researchers plan to use 3D printing technology to create models through which they can observe the behavior of various substances passing through them. After all, sharks typically eat fish, invertebrates, mammals, and even sea grass. They also plan to explore this with engineers, hoping to apply shark intestine designs in industry, for example, for wastewater treatment or microplastic filtration.
However, to be fair, Nikola Tesla was ahead of them by 100 years.
This study was published in the journal Proceedings of the Royal Society B.
