Final answer:
Gibbons are the best brachiators among primates and have distinct vocal calls. They use a range of vocalizations to communicate, which, while complex, do not match the productivity of human language. Primates have evolved arboreal adaptations due to their tree-dwelling heritage.
Step-by-step explanation:
The primates that are the best at brachiation, which is swinging through trees using the arms, are the gibbons. Gibbons are known for their remarkably long forelimbs, a key adaptation for their brachiating lifestyle. They also have rotating shoulder joints and a significant separation between their big toes and other toes, as well as between the thumbs and fingers, to help them grip branches effectively. Additionally, gibbons have a complex system of vocal communication, including elaborate morning duets performed by monogamous pairs that can convey specific information. While these calls and songs are sophisticated and show a certain level of meaning, they are still quite different from human language with its infinite productivity and flexibility.
Chimpanzees are another primate species known for their vocal calls, such as hoots, grunts, and barks, which convey messages such as alerting others to a food source. However, chimpanzee vocalizations do not demonstrate the same complexity and specificity as human language. Meanwhile, all primate species, having descended from tree-dwellers, possess certain arboreal adaptations for climbing, even if not all species are strictly arboreal in their current habitat and lifestyle.