Whales, diverse marine mammals inhabiting the world’s oceans, display a range of fascinating colorations. Their appearances vary significantly across species and even among individuals. These varied hues contribute to their survival and allow for individual identification.
The Spectrum of Whale Colors
Whales exhibit a wide array of colors, from deep grays and blacks to stark whites, and sometimes bluish or brownish tones. Most whales tend to be various shades of light to dark gray, blue, or black, which can lighten or darken with age. For instance, the blue whale, the largest animal on Earth, is typically bluish-gray, appearing purely blue when submerged. Humpback whales are predominantly black, but individuals often have varying amounts of white on their pectoral fins, bellies, and the undersides of their tail flukes. Southern Hemisphere humpbacks tend to have more white markings than those in the Northern Hemisphere.
Beluga whales are born dark gray or brownish, but their skin progressively lightens to become entirely white as they reach maturity, typically between five and twelve years of age. This distinctive white color is why they are often called “white whales.” Killer whales, also known as orcas, are easily recognized by their striking black and white patterns. They are mostly black on their upper bodies with white chests, and feature white patches behind their eyes and on the underside of their tail flukes. Other species include the gray whale, which is dark grayish slate with white spots, and fin whales, which have sleek, grayish-brown bodies with an asymmetrical white patch on the lower right side of their jaw.
Why Whales Have Their Colors
The coloration observed in whales serves several biological and evolutionary purposes, primarily aiding in survival within their marine habitats. A common adaptation is countershading, where an animal’s underside is lighter than its dorsal side. This pattern allows for camouflage: a whale’s dark back blends with the deep ocean water when viewed from above, and its lighter underside blends with the brighter surface light when seen from below. Orcas, for example, use this black-and-white countershading to appear less distinct to both prey and predators.
Beyond camouflage, some coloration patterns can obscure a whale’s body outline, a form of disruptive coloration. The bold contrast in orcas’ black and white markings can make them seem deceptively smaller or help them coordinate during hunts. Coloration also changes with age, as seen in beluga whales whose white adult coloration helps them camouflage among Arctic ice. Their dark color at birth is due to melanin, which gradually decreases as they age, allowing their skin to turn white. This color change plays a role in their adaptation to their icy environment.
Beyond Basic Colors: Unique Markings and Patterns
Beyond their primary body colors, whales often display unique markings and patterns that contribute to their individual appearance and assist in identification. Many whales carry natural markings like callosities, which are rough, calcified skin patches found on right whales, often covered in whale lice. These callosities form unique patterns that allow researchers to identify individual whales. Barnacles are another common sight, attaching to the skin of baleen whales and sometimes toothed whales, forming visible clusters that can weigh hundreds of pounds. While generally considered commensal, meaning the barnacles benefit without significantly harming the whale, they can leave white scars when they detach.
Environmental factors also influence a whale’s appearance. Diatom films, microscopic algae that grow on the skin, can give some whales, particularly blue and fin whales, a yellowish or brownish hue. These films are more common in colder waters and can indicate a whale’s recent migration history. Scars from encounters, such as the distinctive circular marks left by cookiecutter sharks, are also visible on many whale species and can persist for extended periods, contributing to an individual whale’s unique “fingerprint.” Orcas also possess white eye patches that are unique to each individual, serving as a recognition tool for other orcas and potentially acting as a false target to protect their actual eyes.