While many animals have pink tongues, some display a surprising range of hues, including deep blues, purples, or black. These distinctive colorations are not merely aesthetic but often reflect unique biological adaptations related to an animal’s environment, diet, or genetic makeup.
Animals with Naturally Dark Tongues
Several animal species possess naturally dark tongues, ranging from blue to black. The giraffe, a towering herbivore, exhibits a dark purple, blue, or black tongue, particularly towards the tip, while the base remains pink. This long organ, measuring up to 18 to 20 inches (45-50 cm), is adept at stripping leaves from thorny trees. Okapis, close relatives of giraffes, also have long, dark tongues that are often black or purple.
Among domesticated animals, certain dog breeds are recognized for their dark tongues. The Chow Chow is well-known for its solid blue-black tongue, a trait that develops as puppies mature. Similarly, the Chinese Shar-Pei also features a blue-black tongue, which can be solid or spotted. This shared characteristic suggests a distant genetic relationship between the two ancient Chinese breeds.
Polar bears, iconic inhabitants of the Arctic, also possess dark tongues. While their tongues are pink at birth, they gradually darken to a blue or black color as they age, sometimes appearing mottled. Additionally, some blue-tongued skinks, native to Australia, display vibrant blue tongues which they flash as a defense mechanism. Rare melanistic variations of these lizards can have entirely black tongues.
The Biological Reasons for Dark Tongues
The dark pigmentation in these animals’ tongues primarily stems from melanin, the natural pigment responsible for skin and hair color in many species. Melanocytes, the cells that produce melanin, are present in oral tissues, and their activity determines pigment concentration. The amount of melanin produced is largely determined by genetic factors, leading to inherited traits like the blue-black tongues seen in certain dog breeds.
For some animals, a dark tongue is an evolutionary adaptation offering specific advantages. In giraffes, for example, the dark coloration of their tongues is believed to provide protection against the sun’s ultraviolet (UV) rays. Giraffes spend long periods foraging for leaves high in trees, exposing their tongues to intense sunlight. The high concentration of melanin acts as a natural sunscreen, absorbing UV radiation and preventing sunburn or cellular damage.
While sun protection is a prominent theory, other factors may also contribute to dark tongue coloration. For giraffes, their tongues’ robust nature also helps protect against thorns found on their preferred food sources.