Last updated on February 4th, 2022
Today I came across a unique question put forward by my nephew; he asked me if I knew of any animal that doesn’t have ears.
It got me thinking because animals need ears to hear if a predator is approaching. Whether you think of carnivores or herbivores, without ears, these animals won’t be able to defend themselves.
But when asked, I couldn’t seem to remember animals without ears, except certain reptiles! But they, too, need to have specific organs that will help them to ‘hear.’
In other words, adequate hearing is necessary for the creature’s survival in the animal kingdom.
Animals without ears:
- Harp Seals
- Duck-billed Platypus
But what I understand is that several animals don’t have external ears. However, the absence of external ears doesn’t deter them from being aware of their surroundings.
So I decided to learn more about animals without ears and their ability to hear.
Here are seven animals that don’t have ears.
A good majority of bird species don’t have external ears and you’ll never come across a bird that has ears as mammals do.
However, that doesn’t mean birds can’t ‘hear.’ Avian creatures like birds can distinguish sounds through a tiny opening on the sides of their head.
This means they can identify whether the sound is coming from above or below them.
If you compare the hearing capacity of mammals and birds, the first difference you’ll come across is that mammals have external ears.
In mammals, the external ears will divert the sound waves to the middle ears, translated to mechanical vibrations. But without any external ears, birds can’t do this.
Instead, birds without external ears listen to sounds that are coming from different directions through their head since this action allows them to transform sound waves in a manner that they can hear as if they had external ears.
Have you noticed the quick movements of the head of a bird? This is when they’re trying to identify a sound and develop their response to it.
Birds can use their heads to screen the sound coming from one angle, while sound waves traveling from the other direction can also elicit a reaction from the bird.
Tortoises can be distinguished from other reptiles thanks to the shells on their backs but do they have ears?
Tortoises don’t have ears and if you observe closely, you won’t see any organ for hearing on a tortoise because the exact location of the ears is behind its eyes and just above the jaws.
Tortoises don’t have ears primarily because the external outgrowth, which can be termed as the ‘ear of a tortoise,’ is entirely hidden by a scale.
However, don’t think that the lack of an external ear will prevent the tortoise from hearing sounds.
In reality, both turtles and tortoises are pretty sensitive to sound. They use vibrations to protect themselves against potential dangers.
If its sense of smell helps a tortoise forage for food, its excellent hearing through vibrations helps the tortoise defend itself from predators.
If a tortoise feels a threatening or dangerous vibration, it’ll quickly recede into its shell and stay there until it’s sure there is no danger.
So yes, a tortoise doesn’t have ears like other animals, especially mammals, but that doesn’t compromise its hearing.
Snakes are another category of creatures belonging to the reptilian family that doesn’t have ears.
These creatures don’t have any ear-like structure that can be considered outer ear or middle ear and if you observe snakes closely, you’ll find no breaks in their scales.
But they do have something like a middle ear bone that connects the middle ear to the jaw bone.
It’s common knowledge that snakes respond to vibrations, and it’s the vibrations that these creatures use to ‘hear.’
But the existence of a middle ear bone allows snakes to listen to a narrow range of frequencies.
Hence, it would be entirely wrong to say that snakes are deaf and can’t hear anything.
For example, a study carried out by experts found that a few different pythons can listen to sounds of frequency ranging from 80 and 160 Hertz.
But you do know that snakes make hissing sounds. These are sounds that the creature usually makes to ward off predators.
But if it can’t hear the sounds, then how is it making the sound? Thus, snakes do hear specific frequencies of sounds, and this is done with the help of their middle ear bone.
The only difference is that they aren’t as well developed as other creatures without ears.
4. Harp Seals
The harp seals or ‘true seal’ found in the frigid waters of the Russia, Norway, Greenland, and Canada fall into the category of animals that don’t have external ears.
They belong to the family of pinnipeds, and they’re excellent hunters. But the intriguing fact about these creatures is that even though they don’t have any external ear flap, they have excellent hearing abilities.
Their aural abilities are at their best when they’re swimming underwater. The harp seals primarily consume fish and they use their hearing to find food and maneuver themselves around underwater.
The seal can distinguish sounds above 60,000 Hz and this makes the harp seals excellent underwater hunters.
But being a pinniped, harp seals often come on land and this is where the aural abilities of the animal change.
Although the true seal doesn’t have external ear flaps, they have a long ear canal that helps them make out most of the sound heard above land.
As a result of this, the seal can also protect itself from predators above ground.
Thus, even without external ears, the livelihood of the harp seals isn’t compromised in any way.
If you’re a pet owner and you have an aquarium, you’ll know that fishes respond to your voice and the sounds you make. But have you ever seen an external ear pinna in a fish?
Fishes don’t have ears like other animals. Instead, they have what are called otoliths or lateral lines that allow them to hear.
Fishes can listen to sounds in frequency ranges of 30 to 1000 Hertz. But you’ll be surprised to know that if these are entirely water-borne sounds, then fishes can detect sound frequencies, ranging from 400 to 2,000 Hertz.
Fishes need to have excellent hearing to protect themselves from predators and to attract mates.
You’d also be surprised to know that there are several categories of fish that sing to attract mates.
The adult male fishes make these sounds to attract the female fishes.
Therefore fishes need to have an excellent sense of hearing to identify sounds to respond to these accordingly.
This hearing capacity of fishes allows the ones kept in aquariums to react to the sounds made by their owners.
This is why when you give food to your fish and make sounds, they swim up to you. It’s not always in response to the food, but also in response to the sounds from you that they’re familiar with.
The octopus is another marine creature that doesn’t have ears. But the thing that distinguishes it from other creatures of the animal family is that the octopus doesn’t have good hearing.
Instead, it can only distinguish sounds within frequencies of 400 Hertz and 1000 Hertz.
It has been observed that octopuses hear the best frequencies of 600 Hertz and they use the statocyst to listen to sounds.
The statocyst is a sensory organ found in many invertebrates, and it primarily works as a receptor for several external stimulants.
It can help with orientation while swimming or help the animal maintain balance, and in the case of the octopus, it helps with the basics of hearing.
The minimum amount of sound that the octopus can hear is with the help of its statocyst.
7. Duck-billed platypus
The duck-billed platypus, or simply the platypus, is a primitive creature but not one that isn’t intriguing.
This is one creature whose ears you won’t find easily. It has no external ears, but that doesn’t mean that it can’t hear.
The platypus can hear through specialized electroreceptors which give them the ability to sense electrical waves that other animals give off via their movements underwater.
The platypus is an excellent swimmer, and its hearing capacity often guides it.
Being a primitive creature, the platypus never developed any external ear flap.
The ear of the platypus is made entirely of cartilage, and there are no bones. The platypus’ furry skin covers the cartilaginous ears of the animal thoroughly.
The platypus uses its powerful hearing to protect itself from predators and also to find food. The platypus feeds primarily on crustaceans, and these can be shrimps and crayfish among others.
Being a carnivore, a platypus needs to find its food and hunt when necessary. A platypus usually sleeps for fourteen hours a day.
Hence, it needs to consume twenty percent of its body weight. For that, the platypus needs a significant amount of food.
To ensure this, the hearing of the platypus has to support its hunting skills.
This helps the platypus find the nutrition it needs despite the fact that it doesn’t have fully developed ears.