Heat maybe? Hair in general helps trap heat, and in the rainforest that’s not so helpful. Hot and humid I imagine you want that sweat to evaporate as fast as possible. All the airflow.

Production operator with IBS pooped on the floor in a clean room. Kinda ick, and they had to call the spill team to clean up the hazard, but not really the employees fault and no one is really upset. Later, IBS employee is elsewhere, more poop is found on the floor. No one comes forward. No one is identified. Management puts out a “Please use the bathrooms” email and calls it a day.