Why Is a Giraffe’s Tongue Purplish Blue?

Found in central and southern Africa on wide stretches of savannahs and woodlands, giraffes are best known for their towering height and strikingly long necks. Another fascinating part of a giraffe’s anatomy is its remarkable tongue, which is a shade of purplish blue and can reach up to 20 inches (50 cm) in length.

Yet while evolutionary biology has offered insights, the exact reason behind the unique coloration of a giraffe’s tongue remains elusive. The leading theory is that the dark color is due to its high concentration of melanin, a pigment that provides protection from the sun’s ultraviolet (UV) radiation and is thought to help prevent giraffe tongues from becoming sunburned as they eat. After all, adult giraffes can spend over 20 hours a day walking and eating, consuming up to 75 pounds (34 kg) of leaves daily. That’s a lot of time spent roaming the savannah in scorching heat, so protection from the intense ultraviolet rays seems like a plausible evolutionary adaptation.

Similarly, the evolutionary explanation for a giraffe’s long, protruding neck is not as simple as one might think. While it is commonly assumed that their necks can grow up to 6.6 feet (2 m) in length to help them reach the highest leaves of trees, scientists have observed that giraffes often scour branches horizontally, challenging the notion that their height advantage is solely for accessing tall trees. This behavior has even been seen when competition for food is fierce, suggesting that their long necks have other roles that are even more important.

One popular hypothesis suggests that the main explanation for the length and strength of a giraffe’s neck is that it can be used as a weapon when males are fighting to establish dominance. Others speculate that the long neck helps giraffes spot distant predators on the horizon. Alternatively, it may help regulate body temperature due to its large surface area.

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