Sharks are interesting creatures that work quite differently than humans. And many people don’t quite understand how their bodies work. In fact, some people say that sharks can drown. But is that really true?
It’s true that sharks, despite being oceanic creatures, can die of drowning and suffocation if they stop moving. But this only applies to a few sharks that have lost their ability to breathe through their buccal cavity.
Read below to learn more about sharks and how they work.
Can Sharks Drown?
The shark, like many other animals, is susceptible to drowning if it is unable to obtain sufficient oxygen from its surroundings.
In contrast to modern sharks, their ancient predecessors didn’t need to swim continuously to keep breathing. Instead, all of them pumped water through their mouths and over their gills in order to breathe. This technique is known as buccal pumping, and it gets its name from the cheek muscles, which are responsible for drawing water into the mouth and passing it over the gills.
Several species of sharks, including nurse sharks, angel sharks, and carpet sharks (also called wobbegongs), continue to use this technique today. Skates and rays, which are closely related to sharks, also breathe in this manner. These animals have a propensity for spending the majority of their time laying on the ground at the bottom of the ocean.
However, as sharks progressed and became increasingly active, this form of pumping fell by the wayside. It was simply a more effective use of energy to force water over your gills while making swimming motions instead of lowering your buccal cavity. This type of breathing technique is referred to as “ram ventilation”.
The majority of sharks are capable of switching between buccal pumping and ram ventilation depending on the situation they find themselves in. They will cease pumping once they begin swimming at a speed that allows them to force the water in more quickly than they could with the pump. The sand tiger shark is a good example of a shark that can change its breathing technique.
Nevertheless, certain sharks have entirely lost their capacity to breathe through buccal pumping, and these are the sharks that would in fact pass away if they stopped swimming and slamming water. These sharks are referred to as obligate ram breathers (or obligate ram ventilators).
Just around two dozen of the more than 400 documented shark species need to maintain this forward swimming motion in order to breathe. The great white, mako, salmon, and whale sharks are all members of this group.
How Do Sharks Avoid Sinking?
The idea that sharks have to swim constantly in order to keep oxygen-rich water flowing through their gills and prevent themselves from drowning is one of the more commonly held assumptions about these fish. But in reality, there is a great deal more to the story than that.
While some sharks, including the great white, tiger, and hammerhead, must swim constantly in order to breathe, a lot of others, like the nurse shark and whitetip reef shark, can still breathe while resting on the sea floor by pumping water by means of their respiratory systems.
There are also other things that help keep a shark afloat in the deep ocean, where other fish are unable to survive for too long.
In fact, being able to freely ascend and descend in different water depths is one of the most remarkable adaptations that sharks have achieved, given that these remarkable predators lack the swim bladders used by bony fish for such purposes.
Instead, sharks rely on the lifting ability produced by their massive pectoral fins, along with the buoyancy provided by their big livers, which consist of an abundance of oil lighter than water.
With their air-filled swim bladders, bony fish are at risk of drowning if they go too deep or too shallow in the water, but sharks don’t have this problem, making them superior predators.
Do Sharks Have a Maximum Speed?
Sharks, like cartilaginous fish, have a specially developed skeleton that allows them to swim effortlessly through the water. They are able to swim more efficiently than we are because their skin is coated with microscopic teeth that disrupt the boundary layer that exists between their body and the water. This lowers the amount of resistance that they experience while swimming.
When sharks swim, they propel themselves ahead by sending a wave that is shaped like an S down their entire body. This wave continues down the body until it reaches its primary propulsive spot, which is the tail, which is utilized for rapid surges of speed for capturing prey.
When they are actively hunting, sharks are capable of reaching speeds of up to 20 kilometers (12 miles) per hour, which is significantly faster than the average human runner can travel. So, if you’re in the water and a shark suddenly appears, there’s a good probability you won’t be able to swim fast enough to get away.
The sleek shortfin mako shark is the fastest known shark, with speeds measured at 31 mph (50 kph) and, according to some reports, as high as 60 mph (96 kph)! It swims so quickly that it can capture swordfish, which are capable of swimming at speeds of over 60 miles per hour.
Do Sharks Sleep?
Considering any kind of continuous motion as a means of survival is exhausting for us humans; after all, we all enjoy taking a break once in a while to snooze out on the sofa. However, it has been discovered that staying motionless requires more energy for sharks than swimming does.
Researchers found that young lemon sharks, which can alternate between breathing techniques, were six percent more efficient at breathing when swimming than when resting, even when resting in a position where the current carried water straight into their mouths.
This may be helpful in explaining what occurs when sharks are put in situations where there is a risk of hypoxia, sometimes known as an inadequate supply of oxygen. In order to take in more oxygen, sharks that use buccal pumping must raise the force of the pumping while simultaneously decreasing the amount of activity they engage in elsewhere in order to preserve their energy reserves.
However, this doesn’t mean that these sharks don’t have a break every once in a while. Scientists have a hard time determining how or when sharks rest because of the obvious difficulty of keeping track of a shark that is continually moving.
A study using a juvenile spiny dogfish suggested that the spinal cord, not the brain, is responsible for coordinating swimming, suggesting that sharks could be able to rest their brains while continuing to swim.
When sharks are in need of some rest, they may take advantage of the several elements that determine the amount of oxygen in the water. These factors include salinity, temperature, and even the time of day.
In the 1970s, researchers on Mexico’s Isla Mujeres explored the area now known as the Caves of the Sleeping Sharks. Reef sharks, who are generally obligatory ram ventilators, were found stationary and still inside the caverns.
Scientists found that the oxygen content of the cave water was extraordinarily high and the salinity was low. Because of these conditions, it was probably easier for these particular sharks to breathe even when they weren’t moving.
There have been numerous reports of reef sharks lying motionless on the bottom of the ocean, both within and outside of caves. The particular mechanism by which this is possible is still unclear to scientists.
Sharks are interesting creatures that can survive in the harshest conditions of the ocean. That’s what makes it so much more fun to learn more about them. We hope this article was helpful in resolving all your questions about these magnificent animals.