The lengths of the limbs of different kinds of primates adapt the animals to their habitual form of locomotion. Quadrupeds tend to have forelimbs and hindlimbs of around the same length. Adaptation to suspension or brachiation tends to involve longer forelimbs. Bipeds and leapers tend to have longer hindlimbs.
What to do: Look at the primate skeletons at this station. Some of these primates are quadrupeds, while one is a biped and one is a knuckle-walker on the ground and moves arboreally by below-branch suspension and climbing.
How do these limb proportions reflect the locomotor pattern of these primates? Why do you think the apes have short trunks? Why do humans have short arms?