Australopithecus, one of the first apes to walk upright had by now evolved. They lived together in complex family groups and showed a considerable degree of sexual dimorphism in which the males were larger than the females. (Males up to 1,5 meters and females only one to 1,2 meters). Being bipedal gave them several advantages above other primates. They had a higher and better viewpoint, which allowed them to be on the look-out for predators and also to spot food over a greater distance in the open grasslands. The patchwork of forest and savannah was an ideal habitat for an upright walking ape, that hadn't lost all its climbing abilities! The trees provided shelter and food in the form of flowers and fruit and their mode of walking allowed them to cover large distances through the open savannah. But bipedalism also had its price. They were probably the slowest primates around and must have fallen prey to the carnivores they shared their home with.
They had well developed colour vision and relied less on smell and more on sight. Their hands were nimble and dexterous and allowed them to use simple tools like sticks to dig out roots and bulbs or break open termite mounds. Their teeth were more human-like. They had lost the canines and their teeth were covered in a thick enamel to help them cope with tough or dirty food. They had also taken to eating meat, supplementing their mostly vegetarian diet with meat they probably scavenged.
Although their brain was only about a third of modern humans, their ingenuity must have given them the edge above other primates, bringing them closer to the top of the food chain, which their descendants will eventually conquer. Australopithecine fossils have been found in Eastern and Southern Africa, among them the now famous "Lucy" and "Taung child". (24)