Section 1.1: The Complexity of Traits

For those familiar with my work, you’ll know I hesitate to use terms like “what is it for” or “is it useful/useless” when discussing traits, whether they are anatomical or biological. This is because a single trait can fulfill various roles, independent of its genetic origin. Take feathers, for example; they are an exapted or “pre-adapted” feature. Biologically, they assist in thermoregulation but also enabled birds to glide and fly. Additionally, many flightless birds utilize feathers for attracting mates, showcasing their role in sexual selection. The process of Exaptation—one of several evolutionary mechanisms, including Natural Selection and Punctuated Equilibria—“redistributes” existing genes or traits within a population, allowing a single trait to potentially fulfill numerous functions.

Section 1.2: The Multifaceted Nature of Sweat

I've been contemplating the idea that human sweat might serve purposes beyond mere temperature regulation. This adaptation has allowed the genus Homo to excel in endurance activities like long-distance running and to cope with high heat. While that’s the primary function of sweat, my observations and experiences with individuals suffering from conditions like hyperhidrosis suggest that sweat may offer several additional benefits:

• Reducing Friction: Sweat acts as a natural lubricant, minimizing chafing between skin surfaces during activities such as running, similar to moving through water.
• Sexual Lubrication: Although perhaps less relevant today, sweat may have served as an effective lubricant during sexual activities in earlier times and helps remove dirt, keeping individuals cleaner during delicate tasks.
• Trapping Foreign Particles: Sweat can help foreign debris like sand or straw adhere to the skin, potentially offering protection against environmental elements like sun exposure.
• Wound Healing: Sweat glands can act as reservoirs of new cells, functioning as “natural bandages” to assist in healing injuries (Rittié et al., 2016). If ancient humans recognized this property, those who sweated might have had enhanced reproductive success.
• Combat Advantage: In physical confrontations, a sweaty individual is more difficult to grasp, making them more elusive. Historically, this could have provided an advantage in escaping predators or maneuvering through tight spaces.
• Extended Phenotype: Sweat can saturate clothing, which dries more slowly than skin, prolonging the cooling effect without requiring additional sweat production. For instance, when wearing a wet shirt, your body might produce less sweat, allowing for better temperature regulation, a strategy beneficial in extreme conditions.

In conclusion, I propose that sweat may serve numerous functions that we are either unaware of or overlooking. While it undoubtedly fulfills its genetically coded purpose, it can also have a myriad of other roles.