This blog post examines the scientific reasons why great white sharks cannot survive long in aquariums: their ram-air respiration method, long-distance migratory habits, extreme stress, and feeding issues.
I love sharks. I like their appearance, and I’m often delighted when I meet people who say, “I saw a great white shark at the aquarium.” However, there’s one crucial point that needs to be made clear when they say that. Great white sharks are a prime example of animals that are virtually impossible to keep in aquariums.
In fact, many aquariums have attempted to keep great white sharks. The reason is simple: since great white sharks appear in the movie “Jaws,” they wanted to show visitors “that very shark.” But the outcome was always the same. The longest recorded survival of a great white shark in an aquarium is a mere 198 days. This means there has never been a case exceeding 200 days. That record is known to have come from the Monterey Bay Aquarium in California, USA, while other cases lasted only days or weeks.
So why are great white sharks so difficult to keep in captivity? People often say it’s because “great whites are sensitive,” but the key lies less in their temperament and more in their breathing method. Great whites are described as breathing using what’s called “ram ventilation.” This means they must keep swimming forward without stopping for water to enter their mouths. This water then passes through their gills, where oxygen exchange occurs. When they open their mouths wide and water enters, it flows out through the gills as oxygen is absorbed. However, if they stop swimming, the water flow ceases. Since their self-pumping ability to draw in water isn’t sufficient, they can struggle to breathe. This means great white sharks have a lifestyle that’s almost like “if they stop, they can’t breathe.”
The problem is that the aquarium environment struggles to meet this condition. Great white sharks require “space to move continuously at sufficient speed and distance.” Yet, no matter how large an aquarium is, it remains a confined space by a great white shark’s standards. These are long-distance migratory predators that travel tens of kilometers daily and even traverse continents seasonally. What happens when you confine such an animal to a narrow tank? They become stressed from repeatedly colliding with walls and glass surfaces, sustaining injuries to fins or snouts in the process. As stress accumulates, feeding declines until they eventually stop eating altogether. Consequently, the physiological and behavioral requirements for survival in the vast ocean cannot be met within an aquarium. For great white sharks, a small tank literally becomes an “unbearable environment.”
It’s not just a problem of respiration and mobility. In the ocean, the great white shark is considered the apex predator, second only to killer whales. However, aquariums constantly expose them to intense lighting, human noise, light reflections, and vibrations. For an apex predator, such an environment becomes a continuous source of stress. As stress intensifies, their behavior becomes rough, they move aggressively, and collisions become frequent.
The feeding issue is also significant. Great white sharks prey on a diverse range of food, including small sharks, rays, large fish, and marine mammals. However, it is realistically difficult to consistently provide such prey in an aquarium. Ultimately, feeding stress accumulates, they become unable to accept most food, and the likelihood of starvation increases significantly.
And this “breathing method that requires constant movement” is not unique to great white sharks. Among fast-swimming fish, there are species that breathe in a similar manner. Tuna, for example, swim extremely fast, efficiently extracting oxygen as water passes through their gills. Consequently, tuna appear to move nonstop 24 hours a day and are known to never fully stop, even when sleeping. They are also sensitive to water temperature changes. Due to these characteristics, tuna are also extremely difficult to keep long-term in tanks. Mackerel also have high oxygen demands and are highly active, making them difficult to maintain long-term in confined spaces. Some sushi restaurant tanks use strong water currents to keep the fish moving, but this too is often noted as unsustainable over time. Similarly, species like bluefin tuna, which can reach top speeds of 100 km/h, are rarely found in long-term aquarium captivity.
In short, aquariums are environments that can relatively well maintain animals that crawl, float slowly, or can change direction in small spaces. Conversely, confining predators that ‘race’ through the ocean within that space is structurally impractical. Therefore, the statement “I saw a great white shark at the aquarium” usually means the person saw another shark, not a great white.
Sharks relatively suitable for aquarium captivity share common traits: First, they can hover (stay stationary while suspended); second, they can change direction in confined spaces; third, they exhibit relatively low aggression; fourth, their oxygen demand isn’t excessively high; and fifth, they are less likely to suffer fatal injuries from colliding with walls.
The sand tiger shark is frequently cited as a prime example. Its scientific name is Carcharias taurus, and it is commonly called the “Sand Tiger Shark” in English. While its name might suggest extreme ferocity, it is actually described as having relatively low aggression and being quite accepting of food. While its appearance may seem more intimidating than a great white shark, its temperament has even been likened to that of a “giant puppy.”
One key reason sand tiger sharks thrive in aquariums is their neutral buoyancy (the ability to remain at a desired position without rising or sinking). Neutral buoyancy reduces the pressure to constantly move, allowing them to remain relatively stable even in small spaces.
Another example is the nurse shark. Nurse sharks move relatively slowly, spend long periods on the bottom, and are described as having a different breathing method (e.g., mouth pumping) compared to some sharks that “must keep swimming” to breathe. However, nurse sharks are nocturnal, so repeated flash photography under strong daytime lighting inevitably causes them stress.
Another shark often brought to mind is the whale shark. Whale sharks are enormous but relatively slow, known for their gentle nature feeding on plankton, and are exhibited only in limited super-large aquariums. However, whale sharks possess a strong instinct for long-distance migration in the wild, making their captivity feasible only in a very small number of facilities.
Meanwhile, a particularly intriguing topic in great white shark discussions is “Where are the great white shark’s breeding grounds?” The location of great white shark breeding grounds has long remained a major mystery. The reason is simple. Great white sharks exhibit behavior patterns that make them difficult to observe around the time of birth, and their migration range is so vast that pinpointing it is challenging. Great white sharks have extremely large annual migration distances, with extensive migrations mentioned, such as between South Africa and Australia, or between Hawaii and Mexico. Even when adults are observed, the fact that young individuals are rarely seen also makes tracking breeding grounds difficult.
Their reproductive strategy is sometimes described as near ovoviviparous, with a long gestation period (e.g., 18 months), limited litter size (e.g., 2 to 10 pups), and a brief birthing window that offers few opportunities for detection. Furthermore, while it is suggested that calves may remain in relatively warm, shallow coastal waters with lower predator pressure after birth rather than deep ocean, coastal areas are difficult for installing research equipment or conducting long-term tracking. Additionally, calves are small, posing constraints on attaching satellite tags, making research even more challenging.
Recently, clues like the observation of a calf with features resembling placental traces in shallow waters off the central California coast around 2024 have been mentioned, raising the possibility that calving may occur closer to the coast than previously thought. However, the conclusion remains that evidence is still insufficient. The calving site could be coastal or offshore, and currently, the most honest answer is ‘we still don’t know.’
Now, let’s move on to how great white sharks find their prey. Great white sharks possess highly developed olfactory organs at the front of their heads. Their structure, featuring a wrinkled surface that increases surface area, is said to give them exceptional scent detection abilities. However, it’s important to note that scents in water don’t spread out in a ‘round’ manner. Instead, they move along currents, forming long, continuous bands or columns. This does not mean the great white shark smells the entire ocean at once, but rather that it strongly detects odors when it happens to enter within that odor current.
Sharks possess independent olfactory organs on both sides of their head, allowing them to estimate the direction an odor is coming from by detecting subtle differences in odor concentration and arrival time. Consequently, when tracking a scent, sharks do not approach in a straight line. Instead, they move in a zigzag pattern, oscillating between the inside and outside of the scent stream before gradually moving toward the direction of increasing concentration. This behavioral pattern is often compared to how hunting dogs follow a scent.
Furthermore, great white sharks do not rely solely on smell to find prey. The prey search process is structured to utilize multiple senses in a stepwise manner. First, they detect prey from tens to hundreds of meters away using their sense of smell, performing long-range detection. As they approach the prey, they continue with mid-range detection by using the fish’s lateral line to sense minute vibrations and currents in the water. Finally, at very close range, they utilize the Lorenzini organs to detect minute bioelectric signals, such as those generated by the prey’s heartbeat.
This integrated multi-sensory detection system—combining smell, lateral line, and electroreception—is considered the key biological capability that has enabled the great white shark to establish itself as the ocean’s apex predator.
So, how should one respond upon encountering a great white shark? Realistically, there is no “perfect method.” However, common advice generally emphasizes maintaining eye contact and calmly creating distance, as turning your back and fleeing can trigger the shark’s predatory instincts. Some argue that a vertical body position may resemble prey, so maintaining a horizontal posture and avoiding unnecessary stimulation like splashing is often recommended. Above all, prevention is more important than post-incident response. Rules are repeatedly emphasized: avoid swimming alone in shark-infested areas, avoid risky behaviors like swimming at sunrise/sunset, during poor visibility, or after drinking alcohol.
Meanwhile, the latter part of the article continues with discussions on shark buoyancy, the evolution of fish, and descriptions of interesting shark species. Sharks are cartilaginous fish, often explained as lacking the swim bladder that bony fish typically use for buoyancy control. Instead, it is frequently mentioned that sharks rely on their large liver (a fatty liver) to assist with buoyancy. An evolutionary explanation is added: the origin of the swim bladder is linked to primitive lung structures. One lineage converted lung structures into swim bladders, becoming bony fish, while another lineage adapted using different methods (e.g., a strategy centered on fatty livers) instead of swim bladders, leading to cartilaginous fish. However, it’s difficult to definitively state that a simple distinction like “bony fish have swim bladders, cartilaginous fish don’t” applies 100% to all species, as biological exceptions are numerous. Various adaptive cases exist, such as species in shallow water environments that compensate by swallowing air into their stomachs.
Furthermore, the comparison continues: even if they appear similar in appearance, the great white shark and the sand tiger shark show significant differences in lifestyle, diet, aggressiveness, and the possibility of captivity. The conclusion is: “Even if they look alike, their ecology is different.”
The narrative expands further to cover the megalodon. The megalodon was a giant shark that existed in the past, estimated to be 14 to 18 meters long and weighing 50 to 60 tons, with a mouth that could open up to about 3 meters wide. Several hypotheses about why it became extinct are introduced. The theory of competition with Livyathans (giant toothed whales) is refuted as lacking persuasiveness due to temporal inconsistencies. Instead, it is discussed that climate change cooled the oceans, altering the distribution of prey (especially whales). The emergence of competitors (early great white sharks, killer whales, etc.), competition for food, reproductive cycles, and population maintenance issues likely acted in combination. Claims such as “Megalodon still lives in the Mariana Trench” are strongly refuted, arguing that water temperature, prey availability, and physiological conditions make this virtually impossible.
Finally, the explanation continues with the hammerhead shark. The hammerhead shark’s head shape is called a cephalofoil, meaning “head (cephalo) + foil,” and can be understood as a structure functioning like a horizontal wing. While it’s commonly misunderstood that a wide head would increase water resistance, this isn’t necessarily the case; the explanation connects this to the advantages in field of vision and maneuverability. Furthermore, while it might seem that widely spaced eyes would reduce binocular vision, research suggests the opposite: the wide field of view and sufficient overlapping areas actually enable excellent stereoscopic vision and distance judgment (e.g., a related paper was published in “Biology Letters” in 2012). Furthermore, cephalopods are advantageous for rotation and directional changes, aiding in tracking agile prey, and the widely distributed Lorenzini organs in the head region provide benefits for electroreception.
In summary, sharks are not merely objects of simple emotions like “scary/not scary,” but sophisticated creatures where respiration, buoyancy, senses, movement, and reproduction are intricately interlinked.
Furthermore, sharks visible in aquariums are typically limited to species adaptable to that environment. Understanding this allows for a more accurate appreciation of aquarium sharks and enables a more realistic assessment of what poses a danger and what to be cautious of when encountering sharks in the ocean.
