Home » On the Tip of the Tongue: Vertebrate Tongue Adaptations

On the Tip of the Tongue: Vertebrate Tongue Adaptations

Source: http://troutster.com/trout-species/cutthroat-trout/

Look in the mirror, then stick out your tongue and say, “Aw”.  What you see is a muscular organ protruding from your mouth, an organ that contains no bones and averages about 3.5 inches long.  We use it to speak, chew, taste, swallow, natural cleaning of teeth, and for licking ice-cream cones.  Our tongue’s upper surface is covered in taste buds that are located in the lingual papillae, or all the bumpy texture we all see when we stick out our tongue.  Do all vertebrates have tongues?  If they do, are they like ours?

Do other vertebrates have the same needs as us?  Everyone has seen photos of long rough lion tongues, larger versions of house cat’s tongue, grooming themselves or their cubs – but are all tongues so similar?  Some vertebrates eat insects.  Perhaps our minds may all leap to anteaters or frogs that use their tongues to snag their prey but it is the chameleon that my mind goes to.  A chameleon tongue projects out to catch its prey within a fraction of a second.  The tongue  is twice as long as its body and tail combined.  Or the bizarre, egg laying mammal, the echidna, whose long sticky tongue reaches out for insects on the forest floor and returns them to their toothless mouth.  How handy!  Come to think of it my eye itches, so I scratch it with my hand.  If I were a giraffe I would just wrap my tongue around to my eye and scratch that itch.  Giraffe tongues are very long and hardwearing, they need to be to wrap around the thorny acacia branches and leaves that they eat out on the African savanna.

There are many different diets and feeding behaviors in the vertebrate world and they can, and do, vary significantly from our own.   Filter feeders and nectivores are two separate categories of feeding behavior  that have distinctly different tongues form us.  For example, a well-known nectivore is a hummingbird.  Anna’s Hummingbird is one species that travels through Montana. Their tongues are long with a brush-like end that is used to carry the nectar of flowers back inside their mandibles (beak) when they retract it.  Flamingos are filter feeders and so are some ducks, such as the Northern Shoveler, which we find locally.  Their tongues are bizarre bristly looking things as well but the ‘bristle’ is for a different purpose.  They have built-in filters on their bills and use their tongues as pumps to pressure the water through their bill.  Essentially, their tongues are water pumps.

In addition to being for specific purposes, bird tongues also have bones in them and are quite strong.  Aside from having bones in their tongues, California Condors have inward facing serrations on their tongue to help pull food in, they feed on messy carcasses that they found already dead.  While Cutthroat Trout, a species native to our Clark Fork watershed, catch live food, they also have rough serrations or barbs on their tongues, except, technically it is not a tongue.  Their ‘tongue’ is a bony structure called a basihyal.  Cutthroat use the barbs on their basihyal to hold prey against the roof of their mouth to secure it.  There are a wide variety of tongues out there with distinctly different morphologies and uses.  Take a look for yourself, there is bound to be something interesting.

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