Between 70,000 and 100,000 years ago, Homo sapiens began migrating from the African continent and populating parts of Europe and Asia. They reached the Australian continent in canoes sometime between 35,000 and 65,000 years ago.

Crocodiles, lizards, turtles, pythons, and other reptiles proliferated during this time, as did birds such as ducks, geese, hawks, and eagles. Larger versions of contemporary animals such as sloths, venomous lizards, marsupials, and armadillos roamed the landscape, before they were doomed by natural selection.

Homo erectus is considered a highly variable species, spread over two continents (it's not certain whether it reached Europe), and possibly the longest lived early human species - about nine times as long as our own species, Homo sapiens, has been around!

Early African Homo erectus fossils (sometimes called Homo ergaster) are the oldest known early humans to have possessed modern human-like body proportions with relatively elongated legs and shorter arms compared to the size of the torso. These features are considered adaptations to a life lived on the ground, indicating the loss of earlier tree-climbing adaptations, with the ability to walk and possibly run long distances.

Compared with earlier fossil humans, note the expanded braincase relative to the size of the face. The most complete fossil individual of this species is known as the ‘Turkana Boy’ – a well-preserved skeleton (though minus almost all the hand and foot bones), dated around 1.6 million years old. Microscopic study of the teeth indicates that he grew up at a growth rate similar to that of a great ape. There is fossil evidence that this species cared for old and weak individuals. The appearance of Homo erectus in the fossil record is often associated with the earliest handaxes, the first major innovation in stone tool technology.

The tall bodies and large brains of Homo erectus individuals required a lot of energy on a regular basis to function. Eating meat and other types of protein that could be quickly digested made it possible to absorb nutrients with a shorter digestive tract, making more energy available faster. There is also speculation that honey and underground tubers may have been significant food sources for Homo erectus.

Soon after we see evidence in the fossil record of the earliest Homo erectus fossils (by about 1.9 million years ago), we see evidence in the archeological record for the first major innovation in stone tool technology (by about 1.76 million years ago). Known as the Acheulean stone tool industry, it consisted of the creation of large cutting tools like handaxes and cleavers. Increased reliance on a broader set of tools may have helped Homo erectus survive during changing climates.

The earliest evidence of hearths (campfires) occur during the time range of Homo erectus. While we have evidence that hearths were used for cooking (and probably sharing) food, they are likely to have been places for social interaction, and also used for warmth and to keep away large predators.