The Sensory World of Cetaceans and Captivity

By Rosemary Ellis

Cetaceans — whales, dolphins, and porpoises — are tuned into their environment, thanks to their incredibly advanced senses. Sound is their primary sense, with hearing and sound projection playing a crucial role in communication and echolocation, as sound travels faster in water than in air, while sight is impaired by moving through water. But their whole sensory world gets thrown off when trapped in concrete tanks, causing serious problems.

The Sensory Superpowers of Cetaceans

Whales and dolphins possess highly developed senses that are finely tuned to life in the vast, dynamic environment of the ocean. Their primary senses include echolocation, hearing, vision, touch, and biomagnetism, all of which are key to how they navigate, find food, and interact with one another. Whales can also taste their food and even use their sense of taste to distinguish between water masses based on salt content. The majority of cetaceans (with one exception, the bowhead whale) lack the ability to sense smell, as odors move slowly in water, and cetaceans travel too quickly to rely on this sense effectively.

• Echolocation: Perhaps the most remarkable of all cetacean senses is echolocation. This biological sonar allows dolphins and certain whales to emit clicks and listen to the echoes that bounce back from objects in their environment. Echolocation provides them with detailed information about their surroundings, including the size, shape, distance, and even the internal structure of objects, such as the fish they hunt or the terrain they navigate. Echolocation is their primary sensory tool, used for finding mates, migrating, communicating, foraging, nursing, caring for young, and evading predators.

• Hearing: Cetaceans have an acute sense of hearing, far superior to that of humans. They can detect a wide range of frequencies, and some species can hear sounds up to 200 kHz, well beyond the human range of 20 kHz. In the ocean, where light is often limited, sound travels long distances and serves as the primary means of communication and environmental awareness.

• Vision: While cetaceans rely more on sound than sight, their vision is still important, especially in clearer, shallow waters. They have adapted to see well in low light conditions, and their eyes are sensitive to the blue-green spectrum of light that penetrates the ocean depths.

• Touch: The skin of cetaceans is highly sensitive, particularly around their heads and blowholes. They use touch to explore objects and communicate with each other, such as through gentle rubbing or nudging. They also use their bodies to send non-verbal cues to other dolphins.

• Biomagnetism: During migration season, whales likely use sonar to help them stay together and follow one another, but they must rely on additional methods to remember and relocate their destination. Many researchers believe that whales use biomagnetism for this purpose. Being able to detect the Earth’s magnetic fields would enable them to detect variations and orient themselves in the ocean. Biomagnetite has been discovered in the brains of whales and dolphins, leading to the widespread belief that marine mammals use magnetism, alongside sonar, to navigate during migration.

How Captivity Warps Their Senses

When whales and dolphins are confined to the small, sterile environment of a concrete tank, their sensory experiences are severely restricted. This confinement, many scientists agree, can have devastating effects on their physical and mental health.

• Echolocation in Tanks: In the wild, echolocation helps them understand vast spaces. In a tank, those sound waves bounce back instantly from the walls, giving them no useful information. With little to explore, they rarely use echolocation in these environments, as the tanks offer no new challenges or stimulation. Imagine having a powerful tool you can’t even use—it would be frustrating and stressful.

• Hearing in Tanks: The acoustics in a concrete tank are nothing like the ocean. Loud music, screams, and cheers, and the constant, repetitive noise from pumps and filters are believed to cause considerable stress to captive cetaceans, who rely heavily on their sense of sound.

• Vision in Tanks: Instead of the endless, changing ocean, captive cetaceans are stuck staring at the same dull surroundings. The lack of visual variety can lead to boredom and even depression. Cetaceans often endlessly swim in circles or lie motionless at the surface, behaviors that do not occur in the wild. Another potential problem is the chemicals, which can irritate the eyes and skin, used in tanks required to kill potential pathogens.

• Touch in Tanks: The smooth walls of a tank offer no tactile stimulation, and with limited social interactions, these animals miss out on the physical contact that’s so important to them.

• Biomagnetism: Cetaceans are often migratory in the wild, covering 35 to 140 miles daily. Captivity in concrete tanks deprives cetaceans of the dynamic, complex, and vast habitats and relationships they naturally experience in the wild and robs them of opportunities to utilize their biomagnetic senses.

The Big Picture: Why This Matters

The sensory deprivation to which captive cetaceans are subjected is a major ethical issue. These intelligent, social animals are stripped of their experiencing the world as they should. It’s not just about their senses—being in a tank affects their health, happiness, and overall well-being. Hence many captive cetaceans die an early death in captivity due to stress, boredom, and likely a suppressed immune system.

Most captive cetaceans, especially those bred in captivity by entertainment facilities, are not candidates for release in the wild. Sanctuaries that offer more natural environments that are a far better alternative, allowing these animals to experience at least some of the sensory richness of the ocean. Seaside sanctuaries can provide a more compassionate future for these incredible creatures.

Cetaceans' senses are perfectly adapted to a life of exploration and communication in a world of sound and motion—the open ocean. When confined to the small, sterile environment of a concrete tank, their sensory experiences are drastically limited, leading to physical and psychological harm. Understanding the impacts of captivity on cetaceans' senses underscores the urgent need to rethink our relationship with and treatment of cetaceans and work towards a future where there are no cetaceans in concrete tanks.

The International Marine Mammal Project (IMMP) of Earth Island Institute is dedicated to phasing out the captivity of small whales and dolphins all over the world. We’ve made a lot of progress in recent years in the US and Europe, but other countries continue to exploit cetaceans for the entertainment of tourists.

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IMMP is working to end the captivity of cetaceans around the globe. We’ve helped pass legislation and supported efforts in many countries that have banned captivity for cetaceans. Your donations can help stop captures of cetaceans in the wild and stop captive breeding. It is time to retire captive cetaceans to seaside sanctuaries, that provide a more natural home but still provide food and veterinary care for these intelligent animals. Thank you for your support!