What new form of thermoregulation had to evolve before bipedal hominids could be successful?

Question

Quizplus · Accepted Answer

Bipedal locomotion increases exposure to the sun, which can lead to overheating. Sweating, which allows for evaporative cooling, is a more efficient and effective way to regulate body temperature than vasodilation or increased blood flow to the head. This is why sweating had to evolve before bipedal hominids could be successful in hot environments.

What New Form of Thermoregulation Had to Evolve Before Bipedal