Have you ever wondered how animals with poor eyesight get around and survive in the wild? Many creatures have evolved incredible adaptations to compensate for their lack of good vision. In this post, we’ll look at some animals with notoriously bad eyesight and examine how they thrive despite this challenge.
From bulky rhinos to tiny moles burrowing underground, nature has devised fascinating solutions to help these visually impaired species find food, avoid predators, and interact with their environments.
Of all the animals in the savannah, rhinos have some of the worst eyesight. Their small, beady eyes see only in black and white and can detect vague shapes from up to 50 feet away. Anything further is a blur, so how do these hefty beasts get around and avoid danger?
The answer lies in their other senses. Rhinos have excellent hearing and smell that guide them towards tasty plants and alert them to predators. Their wide ears can rotate independently to pick up the slightest sounds, and their keen noses can smell water or detect a predator from miles off.
Rhinos also use their sense of touch to explore their surroundings. They have nerve endings concentrated at the base of their nose horn that detect air currents, vibrations, and scents floating by. By sweeping their heads side to side, rhinos build a sensory map of their environment.
As nocturnal creatures, bats rely on their hearing far more than their eyesight to navigate and hunt. Most species are effectively blind, seeing only in black and white and discerning only significant light changes and movement. But bats have adapted incredibly sensitive ears and a unique sonar system to compensate.
Bats can map out their surroundings in complete darkness by emitting high-pitched sounds that reflect off objects in their path. The echoes create a sound picture in the bat’s mind, allowing them to avoid obstacles and zero in on prey with precision.
Different bat species emit different frequencies; some can even tighten their emissions into focused beams to hone in on small insects. This echolocation allows bats to track swift-flying prey and find safe roosts in caves and trees.
As burrowing animals that spend most of their time underground, moles have virtually useless eyes. Their tiny eyes are often covered with fur or skin, blocking out all light. Moles’ eyes lack lenses and receptors for detail, seeing only changes in light intensity. So, how do they get around in pitch darkness? With an ultra-sensitive sense of touch!
Moles have an Eimer’s organ near their nose that detects subtle vibrations and pressure changes. As they tunnel through the earth, moles rely on Eimer’s organ to detect prey movements or obstacles. The star-shaped arrangement of 11 appendages surrounding their nose helps moles feel their way and construct intricate underground tunnel systems. Moles even swim through the soil using their webbed paws like mini shovels!
On the surface, moles create a mental map using their snout to “see” in 3D. By moving their nose over objects, moles can determine shapes, textures, and distances using touch alone. Their incredible tactile skills help these nearly blind critters thrive underground where eyes are useless.
With their charging reputation, you might think bulls have excellent eyesight for spotting red capes. In reality, bulls are pretty short-sighted. Their rectangular pupil shape limits peripheral and long-distance vision, and bulls see in only blues and greens. Anything further than 30 feet away is a blur, about the length of an average living room!
So, how do bulls partake in bullfighting or protect their herd when they can barely see what’s in front of them? Like rhinos, bulls make up for their poor vision with heightened senses of smell, hearing, and taste. Bulls have a highly developed sense of taste, with taste receptor cells covering their entire tongue. By licking objects, bulls explore and identify their surroundings.
Their flexible ears can rotate to pinpoint sounds precisely, and bulls produce a range of moos, bellows, and snorts to communicate. Most importantly, bulls have an incredible sense of smell that allows them to detect predators from over a mile away. Bulls can charge confidently by relying on their other senses even when they can’t see where they’re going.
Deep Sea Fish
In the pitch-black depths of the ocean, eyes quickly become useless. Many fish living thousands of feet underwater can’t rely on vision; some have lost their eyes entirely through evolution! Instead of seeing, deep sea fish have developed extremely sensitive tactile, chemical, and pressure detection abilities.
For example, the anglerfish dangles a glowing lure to attract prey straight to its mouth since it can’t see anything. Other fish, like viperfish and blobfish, have rows of receptors covering their head that detect the slightest water disturbances. The lateral line running along a fish’s side picks up changes in water pressure and vibrations to create a full sensory picture. Deep sea fish can also taste chemicals dissolved in the water to detect predators or prey.
While their eyes have atrophied from disuse, deep sea fish have evolved incredible non-visual senses to thrive in perpetual darkness. From tactile hairs to taste buds, these unique fish demonstrate how senses besides vision can adapt to facilitate survival when you live in the ocean abyss.