An Immense World

The world we know is only a narrow slice of reality. Our human senses allow us to perceive a certain part of this spectrum - colours, sounds, smells or textures. But beyond our perception there are hidden realms that are as fascinating as they are invisible. Ed Yong's book, "An Immense World," invites us into these realms to discover how other animals experience the world. With their unique senses, they perceive reality in ways that are hard for us to imagine - through sound, vibrations, chemical signals or magnetic fields. Yong reveals that each species has its own "umwelt" - a unique world of perception that is the key to its survival. This journey not only teaches us about nature, but also changes our view of our own place in it.

Every animal on Earth inhabits a world that is unique to its own sensory perception, often diametrically opposed to our own. This idea brings us to the fascinating concept of the "umwelt" - the individual sensory universe. For humans, the idea of ultraviolet light is an invisible phenomenon, but for the bee it is a clear navigational map that guides it to nectar. While we observe the splendor of colorful flowers, the bee perceives intricate patterns and light reflection that we will never see. Imagine a world of fish that can perceive changes in water pressure using a lateral line. For them, the ocean is not only a space full of obstacles, but also a dynamic network of signals that warns them of predators or guides them to prey. This mode of perception is invisible and unimaginable to humans, but for these creatures it is a matter of survival. Similarly, bats use echolocation to create a sound picture of the world around them, allowing them to pinpoint the location of flying insects in complete darkness. Historical studies from the 20th century have shown that, despite our technological sophistication, we are only slowly realising how limited our own perception is. In 1959, the mechanism of ultraviolet light detection in bees was discovered, which caused a breakthrough in our understanding of their behaviour. This discovery showed that the world we thought was universal was just one of countless perceived universes. Despite our advanced knowledge, we still struggle with the tendency to perceive the world anthropocentrically, that is, through the prism of the human senses. The book challenges us to transcend this barrier and realize that each species has its own unique view of reality. The world is far more diverse and mysterious than we can imagine. Understanding the sensory worlds of other species is not only the key to protecting biodiversity, but also a way to learn humility and respect for nature. If we can, even for a moment, see the world through the eyes of a bee, a bat or a fish, we can better appreciate the complexity and beauty of the life that surrounds us. This way of looking at the world opens the door to dimensions we never knew existed.

Sound is an essential communication and orientation tool for many species. While humans predominantly hear sound, some animals can "see" it. Echolocation in particular is a fascinating example of how sound is transformed into an image. Bats, for example, make high-frequency sounds that bounce off objects in their environment. Depending on the timing and intensity of the return of these echoes, they can form a three-dimensional picture of space - they perceive not only the location, but also the size, movement and texture of objects. This ability allows them to navigate and hunt in complete darkness. Dolphins have mastered this mechanism to a master level. Using echolocation, they can not only detect obstacles, but even "see" the internal structure of living organisms. Experiments have shown that dolphins can detect pregnancy in other marine mammals or detect objects hidden under the sand. This ability gives them an advantage in the depths of the sea, where light does not penetrate and visual perception is virtually impossible. Historically, echolocation was discovered relatively late. In 1794, Lazzaro Spallanzani, an Italian scientist, experimented with bats and discovered that even blind bats could orient themselves in the air. But it wasn't until the 20th century that evidence that they achieve this through sound waves was brought to light. This discovery inspired technological advances such as sonar, which we use today to navigate submarines or map the seabed. Some people, albeit to a limited extent, are also able to use echolocation. Blind individuals like Daniel Kish have learned to make clicking sounds with their tongues and listen to their reflections, creating mental maps of space. This unique example shows that the human brain can adapt its abilities in extreme situations. Echolocation is an example of how evolution has adapted animals' senses to their environment. It allows us to see, hear and feel a world that is invisible to us. If we try for a moment to imagine the world of bats or dolphins, we find ourselves in a reality full of sound images that are precise, dynamic and beautifully complex. These sensory universes are a testament to the incredible adaptability of nature and its ability to create solutions that go beyond our imagination.

Vibration and movement are subtle but extremely effective communication tools in nature. Many animals, from tiny spiders to large elephants, can sense changes in their environment through vibrations. For them, these subtle movements carry key information about danger, food or social interaction. Elephants, for example, use vibrations to communicate over long distances. Their low-frequency sounds, known as infrasounds, travel through the ground and are picked up by their sensitive feet. This mechanism allows them to warn herds of predators or announce the presence of water. Scientists noticed this ability in the 1990s, when they realized that elephants reacted to threats before other senses could pick them up. Spiders have a similar ability to "listen" to their web. When prey is caught in it, the spider immediately recognises whether it is a small insect or another threat. The vibrations in the web serve as a map on which it reads details of the object's location and movement. In doing so, spiders can distinguish vibrations caused by wind from those that signal the presence of prey, a testament to their remarkable accuracy. In the ocean, vibrations play a key role in the survival of many species. Fish, such as perch, have a lateral line, a sensory organ that allows them to sense movement and pressure changes in the water. This ability is especially important in dark or murky waters where sight does not play a major role. The lateral line not only allows them to detect the presence of predators, but also to synchronize movements in schools, which increases their chances of survival. A notable example is also found in nature on land. Tadpoles in ponds can sense vibrations caused by the movement of predators. This ability allows them to hide or freeze movement in time, reducing the risk of being noticed by a predator. The same principle is used by many reptiles, which can pick up ground vibrations caused by an approaching enemy. Vibration sensing is a unique way that animals "listen" to the world. It is a silent but incredibly effective mechanism that allows them to respond to stimuli that are often invisible or imperceptible to us. This sensory dimension is a reminder that nature is full of incredible diversity that we are only just beginning to understand.

For many animals, the Earth's magnetic field is an invisible compass that guides them on their journeys to find food, homes and breeding grounds. This ability, known as magnetoreception, is a fascinating example of evolutionary adaptation to navigate a complex world. Animals such as sea turtles, birds, fish and some mammals can sense magnetic fields and use them to navigate, giving them incredible precision in moving across vast areas. Sea turtles are masters of navigation. After hatchlings hatch on the beach, they instinctively head for the ocean and later travel thousands of miles across ocean currents. But years later, they return to the exact spot of their birth to breed. Studies show that they can sense the Earth's magnetic field and remember its specific "signatures", allowing them to pinpoint their original locations. Similarly, migratory birds use magnetoreception for their long migrations. For example, the black-headed flycatcher flies thousands of kilometres between Europe and Africa each year. Scientists have discovered that this species perceives magnetic fields through light-sensitive molecules in its eyes, which allow it to "see" the direction of magnetic lines and thus determine the correct route. Fish, such as salmon, are another fascinating example. After spending years in the ocean, they can return to the exact same stream where they were born. Their ability to combine a magnetic field with their sense of smell in the water is a demonstration of how different senses can complement each other to ensure their survival. Interestingly, some terrestrial species also use magnetoreception. Foxes, for example, help themselves to magnetic fields when hunting. Studies have shown that they have a higher success rate when attacking prey if they are facing north or south - presumably because the magnetic field helps them judge distance and direction more accurately. The ability to sense the magnetic field is still mysterious to us, and its exact mechanisms are not fully understood. Anyway, this invisible force serves as a perfect example of how nature can use even the most subtle physical properties of the world to make life easier. It is a reminder that our planet is also an active player in the silent dialogue between animals and their environment.

Electrical impulses in water represent a fascinating way that some aquatic animals communicate, navigate and hunt. This ability, known as electroreception, allows them to sense electrical signals generated by the muscular and nervous activity of other organisms or to generate their own electrical fields to explore their environment. Animals that possess this unique sense use it to survive at depths where light is scarce and sight unusable. Electric eels are among the most famous masters of this skill. These creatures can generate powerful electrical discharges of up to 600 volts, which they use to stun prey, defend against predators, and even navigate. Their body functions like a biological battery made up of thousands of special cells called electrocytes. When they're all activated at once, they create a massive discharge that can be lethal to smaller organisms. Many species of fish, such as the knifefish that live in the tropical rivers of South America, produce weaker electric fields. These help them navigate in murky water where visibility is minimal. These fields distort on contact with other objects or animals, giving the fish an accurate picture of their immediate surroundings. This process is similar to sonar, but uses electricity instead of sound. Rays and sharks, in turn, have sensitive receptors, known as Lorenzini's ampullae, which can pick up the most subtle electrical impulses. These organs allow them to locate prey hidden under the sand or identify vulnerable spots of other animals. In seas and oceans, where competition for food can be fierce, this ability is an advantage that greatly increases the chances of a successful hunt. Research has shown that electroreception has evolved independently in different lineages of animals. This phenomenon is a demonstration of how evolution can repeatedly produce ingenious solutions in different places and under different conditions. It is also a reminder that even the most ordinary environments, such as murky rivers or deep oceans, are full of invisible dynamics. Electrical impulses in water reveal a hidden world where communication and navigation take place through invisible signals. This sensory universe is another reminder of how amazing and diverse nature is - always able to adapt and create systems that surpass our understanding.

Chemical perception is one of the oldest and most versatile senses in nature. It allows animals to react to their environment, communicate and survive. One of the most fascinating forms of chemical perception is the use of pheromones - chemical signals that influence the behaviour of other individuals of the same species. This "invisible language" takes myriad forms, and its importance goes beyond our understanding. Ants are masters at using pheromones. These tiny creatures leave scent trails that serve as maps to food sources. When they discover food, they send a chemical signal back to their colony so that other ants can follow the exact route. However, if the path is dangerous, they send out warning pheromones that cause other individuals to avoid the area. This system is extremely efficient and can coordinate thousands of ants without central control. Butterflies can sense pheromones over incredible distances. The females of these butterflies produce sex pheromones that males can pick up from miles away. These chemical signals are so strong that they can navigate males directly to the source, even when wind or other conditions make travel difficult. Chemical sensing is also key in the aquatic world. Fish, like salmon, remember the chemical signature of the river they were born in. After years spent in the ocean, they return to their place of origin using this "olfactory compass." Studies have shown that they can detect even the subtlest chemical differences between waterways, allowing them to accurately identify the correct river. Mammals, including humans, also use pheromones, although their function is not as pronounced as in insects. For example, many species of mammals use pheromones to mark territory or signal readiness to breed. In humans, chemical perception is less clear, but research suggests that pheromones may influence subconscious decisions regarding social interaction and attraction. Chemical perception is a wonderful example of invisible but powerful communication in nature. Pheromones function as silent messages that can coordinate group behavior, attract mates, or warn of threats. This sensory system reminds us that although many processes in nature are not visible, their influence is essential for the survival and harmony of the entire ecosystem.

Sight, although often considered the most important sense for humans, is remarkably variable in the animal world. Different species perceive the world through unique visual systems that reflect their environment and evolutionary needs. While humans see the world in three basic colors-red, green, and blue-some animals see entirely different spectrums of light that remain hidden to us. Birds, such as falcons or pigeons, are known for their sharp eyesight, which allows them to perceive details over vast distances. But even more fascinating is their ability to perceive ultraviolet light. This range helps them identify ripe fruit, follow scent trails of mates or distinguish between seemingly identical plumage of other individuals. Invisible to us, the ultraviolet patterns on the lips and wings of birds appear to them as glowing signals. Insects, such as bees, have eyesight adapted to analyse the ultraviolet spectrum. This allows them to see patterns on flowers that guide them to nectar. Their eyes have hundreds of tiny lenses that give them a composite picture of the world. This vision is ideal for detecting movements and identifying objects in a dynamic environment such as a meadow full of flowers. On the other end of the spectrum are animals that live in the dark, such as deep-sea fish or bats. Their vision is either minimized or completely replaced by other senses such as echolocation or chemical perception. However, some deep-sea species can sense bioluminescent signals - light produced by other organisms to communicate or attract prey. This ability allows them to survive in environments where there is absolute darkness. Butterflies, like birds, see colors outside our spectrum. Some species can distinguish up to five primary colors, which helps them find suitable mates and food. This vision is particularly useful in tropical forest environments where competition for resources is intense and the right decision can determine survival. The diversity of visual perception shows us how each species has adapted to its environment. The world seen through the eyes of a bird, a bee or a deep-sea fish is not just different, it is completely alien and unimaginable. This variability reminds us that our version of reality is just one of many - rich, but not universal. If we could see the world through the eyes of other species, we would discover an infinite spectrum of colors and signals that elude us.

Humility in worldview stems from the realization that our human perspective is only one of countless versions of reality. Each species perceives the world differently - through unique senses that come from their environment and way of life. This knowledge reveals how limited our ability to comprehend the full range of life on Earth is. Instead of feeling superior, it forces us to reflect on how incomplete and subjective our experiences are. When we look at the world through the eyes of animals, we see fascinating parallel realities. A bee, for example, does not recognize the beauty of a flower as we do - colors and shapes are a navigational system for it to obtain food. A dolphin navigates not by sight, but by echolocation, which allows it to "see" the structure of objects based on sound waves. These differences are not just technical curiosities, but evidence that reality is infinitely variable and shaped by the needs of individual species. Viewing the world as a dynamic, multidimensional system can inspire us to a deeper respect for nature. For example, sea turtles that can travel thousands of miles based on the Earth's magnetic fields, or spiders that sense the vibrations of their webs, reveal not only their abilities, but also the complexity and harmony of the world of which we are a part. This awareness teaches us to let go of an anthropocentric view of the world. Nature is not just made for us, and its value is not only in what it provides. Every species plays a role in an ecosystem that is much larger and more complex than we can imagine. This holistic approach helps us understand that damage to one part of the system will affect the whole, including ourselves. Humility comes from respect for what we do not know. The world through the eyes of a bee, a bat or a shark reminds us that reality is not universal - it is diverse and rich. To realize this is to open the door to a deeper understanding of life and a willingness to protect what we think is ordinary but is in fact extraordinary. In this diversity lies the true splendour of a world that constantly surprises us.

"An Immense World" teaches us humility towards nature. Through fascinating stories about the senses of animals - from the echolocation of bats, to the chemical communication of ants, to the magnetic navigation of turtles - we are reminded that our way of perceiving the world is not universal. Each species has its own sensory filters that connect it to its environment and provide it with the benefits it needs to survive. This diversity is not only interesting, but also essential for ecosystems to function. Yong inspires us to protect nature not only for its practical value, but also for its unique beauty and complexity. The world is not just ours - it is home to billions of parallel realities can teach us more about life if we are willing to see through the eyes of others. Do you have feedback for us? We'd love it if you let us know your opinion on our content! Just send an email to feedback@rewio.app with the title of this book in the subject line and share your impressions!