Tongues Engineered for Insect Catching
Many animals have evolved long tongues for capturing insects, their primary food source. These tongues often feature adaptations like stickiness, rapid extension, or specialized musculature to secure prey. Anteaters, for instance, possess long, slender tongues that can extend up to two feet, nearly twice their head’s length. Their tongues are coated in sticky saliva, allowing them to pick up thousands of ants and termites from nests with quick, repetitive motions.
Pangolins also have an impressive tongue, longer than their entire body, extending from an anchor point near their pelvis. This length allows them to reach deep into ant and termite mounds. Their tongues are covered in viscous saliva that traps insects. Chameleons are known for ballistic tongue projection, launching their tongue to twice their body length in fractions of a second. The tip of their tongue forms a suction cup-like pad that adheres firmly to prey upon impact, pulling insects back into their mouths.
Frogs and toads use a different but effective strategy for insect capture. Their tongues are attached at the front of the mouth, allowing for a rapid, explosive flick outward. These tongues are highly elastic and coated with super-sticky, non-Newtonian saliva. This saliva becomes less viscous during the flick but thickens instantly upon contact with prey, ensuring a strong grip. The speed and stickiness of these tongues make them efficient insect predators.
Tongues Adapted for Nectar Access
Some animals have developed long tongues to access nectar, a sugary liquid found deep within flowers. This adaptation facilitates a co-evolutionary relationship between the animals and the plants they pollinate.
Hummingbirds possess a bifurcated, or forked, tongue that extends significantly beyond their beak. Instead of actively sucking nectar, their tongues are fringed with lamellae. Through capillary action, these wick nectar into two parallel grooves as the tongue is repeatedly inserted and withdrawn from a flower.
Long-tongued bats, such as the tube-lipped nectar bat, have tongues that can exceed their body length, reaching nectar in elongated floral tubes. Their tongues are equipped with brush-like papillae at the tip, which increase the surface area for collecting nectar. These bats play a significant role in pollinating night-blooming flowers.
Moths, particularly hawkmoths, feature a proboscis—a long, tubular mouthpart that functions like a tongue. This proboscis remains coiled beneath their head when not in use. It can unfurl to considerable lengths, enabling them to reach nectar in deep-throated flowers while hovering. The length and flexibility of the proboscis allow these moths to access food sources unavailable to other insects.
Tongues for Diverse Feeding and Grooming
Beyond insect and nectar consumption, long tongues serve various purposes, showcasing their versatility. Giraffes, for example, possess a dark, prehensile tongue up to 20 inches long, which they use to strip leaves and buds from thorny acacia trees without injury, and to manipulate food and groom.
Okapi, relatives of giraffes, have a long, blue-gray prehensile tongue. They use it to strip foliage from branches and clean their eyelids and ears.
Monitor lizards, such as the Komodo dragon, use their long, forked tongues primarily for chemoreception, flicking them out to collect airborne scent particles. The tongue then delivers these particles to a specialized sensory organ in the roof of their mouth, helping them to locate prey and navigate their environment.
Blue-tongued skinks, despite their name, use their tongues for sensing and manipulating food items. While not as long as a chameleon’s, their broader, muscular tongue helps them grasp and consume various small invertebrates and plant matter. These diverse applications show how tongue length and structure adapt to an animal’s specific ecological niche.
The Science of Tongue Extension
Animals rapidly extend their tongues using complex biological and physical mechanisms. Many vertebrates, including chameleons and amphibians, utilize a hydrostatic skeleton within their tongues. The tongue is largely composed of muscle and connective tissue. Its extension is achieved by rapid contraction of intrinsic muscles that change the tongue’s shape and volume, forcing it forward. This process allows for speed and precision without skeletal support along the tongue’s length.
Other animals, such as anteaters, rely on an elongated hyoid apparatus, a bone structure in the neck, which supports and anchors the tongue. Specialized muscles attached to this hyoid bone contract, pulling the tongue out of the mouth with force and speed. The length of these tongues often means the hyoid apparatus extends deep into the chest cavity, providing leverage for protrusion.
Saliva is also important in the functionality of many long tongues. For insect-eating animals, saliva possesses adhesive properties, allowing prey to stick firmly to the tongue upon contact. For nectar feeders, saliva may contain enzymes that aid in digestion or provide lubrication for efficient nectar collection. The coordinated action of muscles, skeletal support, and specialized secretions enables these tongue extensions, facilitating diverse feeding strategies across the animal kingdom.