Whales are often perceived as sleek, hairless creatures perfectly adapted to their aquatic environment. Despite their smooth appearance, whales do indeed have hair, representing a unique biological adaptation for these large marine mammals. This sparse hair offers insights into their evolutionary past and current sensory capabilities.
Specific Locations of Hair on Whales
Whales possess hair in specific areas, primarily concentrated around their head. These small, stiff hairs are often found on the snout, chin, and jawline. In some species, such as right whales, hair may also be present near the blowholes. Humpback whales, for instance, have distinct bumps called tubercles on their heads, each housing a single hair follicle. Gray whales also exhibit scattered hairs around their head, particularly noticeable in younger individuals.
These hairs are sparse and bristly, unlike the dense fur of land mammals. The number of these hairs can vary between species, generally ranging from 30 to 100. These hairs are not for warmth, as whales rely on a thick layer of blubber for insulation. Their location suggests a specialized sensory purpose in their marine habitat.
The Function of Whale Hair
The hair on whales primarily functions as a sensory organ, akin to whiskers on many land mammals. These hairs, known as vibrissae, are deeply rooted in follicles surrounded by a dense network of nerves. This rich innervation suggests they are highly sensitive, enabling whales to perceive subtle changes in their aquatic surroundings. Scientists hypothesize that these sensory hairs assist whales in detecting water pressure changes, movements, and vibrations, which could be valuable for navigating in murky waters or at night, and for locating prey. The hairs may also play a role in social interactions or communication, with some theories suggesting calves might use them to signal their need to nurse.
Hair Across Different Whale Species
The presence and prominence of hair vary significantly between the two main groups of whales: baleen whales (Mysticetes) and toothed whales (Odontocetes). Species like humpback, fin, sei, right, and bowhead whales typically retain hair follicles and often visible hairs into adulthood. Bowhead whales, for example, can have over 300 hairs on their chin and upper lip.
In contrast, most toothed whales, including dolphins and porpoises, only possess hair briefly during their embryonic or fetal development. They usually lose these hairs before or shortly after birth, making it a largely vestigial trait for adults. A notable exception is the Amazon river dolphin, which retains stiff hairs on its snout throughout its life. These hairs are thought to aid the Amazon river dolphin in finding food in muddy river bottoms where visibility is limited. While many toothed whales lose their hair, the underlying hair follicles often remain, suggesting they may still contribute to sensory perception even without a visible hair shaft.