Final answer:
The Lesser Gluteal Muscles in humans serve as hip abductors and stabilizers, unlike in other primates where they primarily act as hip extensors.
Step-by-step explanation:
The Lesser Gluteal Muscles (Gluteus Medius and Gluteus Minimus) are hip extensors in other primates but are hip abductors or "stabilizers" in humans. The gluteus medius is a muscle deep to the gluteus maximus that abducts the femur at the hip, while the gluteus minimus is the smallest of the gluteal muscles and is located deep to the gluteus medius.
These muscles are part of the gluteal group which is responsible for various movements and stabilization of the femur. In humans, the gluteus medius and gluteus minimus play a crucial role in stabilizing the pelvis when standing on one leg and during locomotion. Their adaptation is significant for bipedalism, contrasting with the extensive role of similar muscles in other primates for climbing and knuckle-walking.