There’s no denying that fish are strange creatures, there always seems to be something new we can learn about them. I recently heard about a food called fried cod tongue and this got me thinking about whether or not fish actually have tongues. I’ve never seen a fish tongue but I set out on a mission to find out the truth.
Do fish have tongues? Many fish species do have tongues, but they are not the same as mammal tongues. While mammals have muscular tongues that is used for tasting, chewing and swallowing, a fish’s tongue is a bony structure formed from the floor of the mouth that serves to protect the ventral aorta.
Not all fish species have tongues and those that do can actually end up losing their tongue due to parasites. Some fish tongues even have teeth although the teeth aren’t necessarily for chewing the food but can actually assist in swallowing prey, more on that later.
What is a Fish Tongue?
A fish tongue, called a basihyal, is a bony structure that is positioned on the floor of the mouth. The basihyal does resemble a tongue so if you do happen to catch a glimpse of it you may think that it is a tongue that has the same functions as ours.
However, unlike a mammal’s tongue, the basihyal is not muscular and does not have taste buds, so although it is in the same location as a mammal’s tongue it is not directly equivalent.
To put it simply, a fish tongue is effectively an extension of the base of a fish’s mouth. Scientists believe that the basihyal evolved to protect the ventral aorta which is located close to the mouth of a fish and could potentially become damaged by prey. The ventral aorta is the artery that carries blood from the heart to the aortic arches.
Key Differences Between Mammal and Fish Tongues
|Mammal’s Tongue||Fish’s Tongue|
|Muscular organ||Bony structure|
|Located on the floor of the mouth||Located on the floor of the mouth|
|Enables sucking||Helps transports food quickly through the mouth|
|Important to aid in chewing and swallowing||Helps move oxygenated water through gills|
|Major bearer of taste buds||Sometimes assists in the chewing of food|
What Are Cod Tongues?
Earlier I mentioned that it was fried cod tongues that got me thinking whether or not fish have tongues, so what actually are cod tongues? You may have seen cod tongues on the menu but they are not what you may think.
Despite the name, the fried cod tongues are not tongues at all and they aren’t basihyal either. So, ironically, the very thing that led me to find out that many fish do have tongues, is not a tongue at all! The ‘cod tongues’ are actually a muscle that is taken from the back of a cod’s neck. This muscle is then battered, seasoned and fried to create a delicacy known as fried cod tongues.
Teeth on Fish Tongues
Some fish tongues have teeth on them. That’s right, you heard me right. There are fish tongues that have teeth on them. As odd as this sounds, they do have a purpose.
Interestingly, for some species the tongue teeth are not designed to assist in the chewing of prey but are actually used for helping fish to swallow their prey. The teeth are pointed backwards which means prey cannot move back towards the front of the mouth and can only move in the direction of the throat.
Brown University supported this idea with research into how fish and mammals chew differently, describing how many fish use the tongue to thrust food backward into the mouth while mammals use their tongue to position food for grinding.
Konow and colleagues published papers showing the chewing technique of some fish species that have teeth on their tongues. They found that in some of these species the chewing motion is actually creating by the tongue, it begins with the tongue positioned in the upper mouth and is then pulled downward and backwards then forwards and upwards.
Parasites That Invade Fish Tongues
Teeth aren’t the only thing you may find on a fish tongue. There are some parasites that attack the basihyal, or tongue, of fish. An example of this is parasitic crustaceans that pierce the base of the tongue so that it will eventually become detached allowing the parasite to then ‘replace’ the tongue.
These parasitic tongue biters are known to survive off of the host’s blood or mucous. There are some misconceptions that these parasites survive by eating scraps of the food the fish eats but this is not the case. Evidence suggests that the parasites do not kill the host but they do often feed off of the tongue until it is gone and then take the place of the tongue.
|Parasite||What it does||Host Symptoms|
|Cymothoa exigua a.k.a tongue-eating louse||Consumes and replaces hosts tongue||– Cuts to buccal cavity|
– Anemia as a result of cuts
– Damaged gill tissues
– Respiratory issues
How Do Parasites Attach Themselves to Fish Tongues?
The parasitic crustaceans, or isopods, first attach themselves to the fish’s gills. If the tongue is unoccupied the parasite will move from the gills to the tongue. This is where the parasite will consume and replace the tongue.
According to research by Denham Parker of Rhodes University, the tongue-biting isopods start as males but then transform into females when they attach to the fish’s tongue. Then if a male then attaches to the fish’s gills the parasites breed and the female will release fertilized eggs into the water.
Can Fish Survive with Tongue Parasites?
A fish can survive if they have tongue parasites but their growth may be impacted. Eating and breathing will be more difficult for the fish when they have tongue parasites but the fish will, in most cases, outlive the parasites. The parasites will stay until either the fish dies or the parasite dies.
Talking about fish tongues bring up so many other questions. Here are the answers to some of the most frequently asked questions:
Are There Any Animals That Do Not Have Tongues?
Not all animals have tongues. A few examples of animals that naturally do not have tongues include:
- Sea Urchins
- Sea Stars
- Pipidae (tongueless frogs)
The way animals eat without tongues depends on the individual species. Some swallow their prey whole, some push their stomach out through their mouth to take in the prey, some such as butterflies, even taste with their feet.
Do Goldfish Have a Tongue?
As one of the more popular fish to keep, many goldfish owners want to know about goldfish behaviour and anatomy. Goldfish are one of the species that do have a tongue (a basihyal) so if you look closely when they open their mouths you may see the bony structure along the bottom of their mouth.
Do Fish Have Taste Buds?
We often associate taste buds with tongues but this is different in fish. Fish do have taste buds, but their taste buds are on the inside of their mouth and around the outside of their body, often on the outside of their lips. Taste buds need to be moist but as fish live in water the taste buds can survive on the outside of their body as well as within their mouths.
Having taste buds inside and outside of their mouths allows fish to find food more easily. As an example, the Catfish has over 100,000 taste buds across its body and on its barbels – a far higher number of taste buds than many other animals. In comparison, humans only have around 5,000 taste buds in their mouths.
Do Fish Have Teeth?
Fish do have teeth and depending on the species the teeth may be found in the:
- Upper and Lower Jaws
According to Florida Museum, the type of teeth a fish has depends on their diet. Just like in mammals, the fish that eat other fish (carnivores) have sharp teeth designed to puncture, hold and cut their prey while the herbivores have teeth suited to shredding plant materials such as algae.