Ears are a common feature among animals, serving a variety of purposes such as hearing, balance, and communication. However, some animals have evolved to do without ears or have greatly reduced ear structures. Here are 15 examples of animals without ears or with significantly reduced ear structures.
1. Star-Nosed Mole
The star-nosed mole is a small, insectivorous mammal native to the eastern United States and Canada. Its most distinctive feature is the ring of 22 pink, fleshy tentacles around its nose, which it uses to locate and identify food. Despite its lack of visible ears, the star-nosed mole is able to hear, thanks to a small pair of ear bones located deep within its fur. These ear bones, known as “colleters,” vibrate in response to sound waves and transmit the information to the mole’s brain.
2. Sea Snake
Sea snakes, also known as coral reef snakes or aquatic cobras, are a group of highly venomous snakes found in the tropical waters of the Indian and Pacific Oceans. They are adapted for life in the water, with a flattened tail and laterally compressed body that allow them to swim efficiently. Sea snakes lack external ears and ear openings, but they are still able to hear underwater. They have a special bone in their lower jaw, called the columella, that vibrates in response to sound waves and transmits the information to their inner ear.
3. Hammerhead Shark
Hammerhead sharks are a group of shark species characterized by their distinctive hammer-shaped heads. There are nine known species of hammerhead sharks, ranging in size from 3 to 20 feet in length. Hammerhead sharks have small, rudimentary ears, but they do not rely on hearing to detect prey. Instead, they use their keen sense of smell and electrosense (the ability to detect the electric fields produced by living organisms) to locate food.
4. Pythons
Pythons are a group of non-venomous snakes found in Africa, Asia, and Australia. They are known for their powerful bodies and ability to constrict their prey. Pythons do not have external ears or ear openings, but they are still able to hear through the bones in their lower jaw, which transmit vibrations to their inner ear.
5. Lampreys
Lampreys are a group of jawless, parasitic fish found in freshwater and coastal waters around the world. They are primitive creatures with a simple, eel-like body and a circular, sucker-like mouth lined with sharp teeth. Lampreys do not have ears or a well-developed sense of hearing. Instead, they rely on other senses, such as smell and touch, to locate their hosts and prey.
6. Jellyfish
Jellyfish are aquatic animals with a soft, gelatinous body and tentacles that trail from their bell-shaped bells. There are thousands of known species of jellyfish, found in every ocean on Earth. Jellyfish do not have ears or a centralized nervous system, but they are still able to sense their environment through specialized cells called sensory receptors. These receptors allow jellyfish to detect changes in light, temperature, and the presence of other organisms.
7. Flatworms
Flatworms are a group of simple, bilaterally symmetrical animals found in freshwater, marine, and terrestrial environments. They have a flattened body and a primitive, diffuse nervous system.
8. Tapeworms
Tapeworms are a type of parasitic flatworm found in the intestines of animals and humans. They have a long, segmented body and lack a mouth, digestive system, and circulatory system. Tapeworms do not have ears or a well-developed sense of hearing. Instead, they rely on chemical signals to locate their hosts and detect changes in their environment.
9. Starfish
Starfish, also known as sea stars, are marine invertebrates with a radial symmetry and a star-shaped body. There are over 2,000 known species of starfish, found in every ocean on Earth. Starfish do not have ears or a well-developed sense of hearing. Instead, they use their sensitive tentacles and tube feet to touch, taste, and smell their environment.
10. Sponges
Sponges are simple, aquatic animals with a porous body that filters water for food and oxygen. They are sessile, meaning they do not have the ability to move or seek out food. Sponges do not have ears or a well-developed sense of hearing. They do, however, have specialized cells called sensory receptors that allow them to detect changes in light, temperature, and the presence of other organisms.
11. Sea Cucumbers
Sea cucumbers are soft-bodied, cylindrical marine invertebrates with a leathery skin and long, flexible tentacles. There are over 1,700 known species of sea cucumbers, found in every ocean on Earth. Sea cucumbers do not have ears or a well-developed sense of hearing. Instead, they use their tentacles and tube feet to touch, taste, and smell their environment.
12. Sea Urchins
Sea urchins are spiny, spherical marine invertebrates found in every ocean on Earth. They have a hard, calcified exoskeleton and a mouth located on the underside of their body. Sea urchins do not have ears or a well-developed sense of hearing. Instead, they use their tentacles and tube feet to touch, taste, and smell their environment.
13. Scorpions
Scorpions are arachnids with a venomous stinger on the tail and pincers on the head. There are over 1,700 known species of scorpions, found on every continent except Antarctica. Scorpions do not have ears or a well-developed sense of hearing. Instead, they use their sensitive hair-like structures, called pectines, to detect vibrations and changes in air pressure.
14. Spiders
Spiders are arachnids with four pairs of legs and two main body segments. There are over 45,000 known species of spiders, found on every continent except Antarctica. Spiders do not have ears or a well-developed sense of hearing. Instead, they use their sensitive hair-like structures, called trichobothria, to detect vibrations and changes in air pressure.
15. Centipedes
Centipedes are elongated, many-legged invertebrates found in a variety of terrestrial and aquatic environments. There are over 8,000 known species of centipedes, found on every continent except Antarctica. Centipedes do not have ears or a well-developed sense of hearing. Instead, they use their sensitive hair-like structures, called sensilla, to detect vibrations.