Homo Erectus: The Most Successful Human?

Evolution is all about survival. The species that are best adapted to their environments are the ones that survive the longest. If this metric is used to measure evolutionary success, then it becomes clear that Homo erectus is the most successful species of human to have ever walked the earth. In contrast to our own species, Homo sapiens, which has been around for approximately 300,000 years (a major feat in itself), Homo erectus lived for 1.5 million years before going extinct.

Thus, of all our ancestral species, Homo erectus lived for the longest time. But who were these ancestors of ours? Where did they come from, and what made them special?

How Homo erectus came about is subject to debate. There are several major theories about where they evolved and from whom they evolved. It is generally agreed upon that Homo erectus evolved from Homo habilis, the first species to be considered part of the Homo genus.

One theory is that H. erectus evolved from H. habilis 2 million years ago. However, the two species seemed to have lived at the same time for half a million years. It is suggested that H. erectus evolved solely from a genetically isolated population of H. habilis.

There are also various naming conventions that cause confusion. An example of this is that some academics refer to the entire species as H. erectus, while others use H. erectus only to refer to the species in Asia and refer to the African variant as Homo ergaster.

It is thought that from H. erectus another species evolved, with Eurasian specimens being referred to as Homo heidelbergensis and African specimens being referred to as Homo rhodesiensis. Homo neanderthalensis, Homo denisova, and Homo sapiens (us) evolved from this species.

Homo erectus was widespread across Africa and Eurasia and present for over 1.5 million years. As a result, many regional and time-based adaptations exist that distinguish different groups or subspecies of H. erectus. They were slightly shorter and lighter than modern humans, although evidence shows they could reach over 6 feet tall. There does not seem to be much evidence showing a huge disparity in sexual dimorphism. Size differences seem to be similar to those of modern humans.

They had prominent brow ridges, prognathism (protruding mouth features), and foreheads that sloped back; although in all these cases, the features were less pronounced than their biological ancestors, Homo habilis, and the australopithecines that came before them.

Their cranial capacity varied massively over time, from roughly 550 to 1250 cubic centimeters (modern human brain capacity is approximately 1400 to 1500 cc).

Their bone structure was very similar to modern humans and suggested that they moved in relatively the same way that we did. One curious difference is that the palms of their hands were turned slightly forward-facing, as opposed to ours, which rest parallel to and facing our outer legs. Like us, H. erectus was adept at throwing – an evolutionary advantage that helped put our genus on top of the food chain.

H. erectus was the first species that resembled us in terms of lack of fur. During the first few hundred thousand years of their existence, it is likely that this was when our genus lost our fur. This was another advantageous evolutionary trait, as it resulted in the body being able to use the entire skin surface to sweat and thus be far more efficient in cooling down. While being hunted, animals with fur would simply overheat and tire out while being pursued by the slower but far more energy-efficient H. erectus predators.

Due to the long span of their existence and the various adaptations of the subspecies, there is no single culture that can define such a large and varied species and all its extant groups. There are, however, individual examples that can be used to define cultures within the umbrella term of Homo erectus.

For the most part, there seems to have been a loose division of labor whereby the males hunted game and did more dangerous tasks while the females spent their time gathering safer food. The increase in brain size from Homo habilis to H. erectus, and throughout the existence of H. erectus, is generally thought to have been the result of an increased caloric intake from meat. This went hand in hand with a reduced gut size, as longer intestines were no longer necessary for dealing with a plant-heavy diet.

The culture of these hominids is also directly related to their level of technology and the tools they used. While Homo habilis was the first to use stone tools, these were simple lithic flakes and lacked the features that would make the tools identifiable as being created for various individual purposes. H. erectus created tools specifically to be scrapers, hand axes, choppers, cleavers, and hammers.

These tools lacked the complexity of the tools created by later hominids, but they definitely represent a huge leap forward in evolutionary ability. They show that H. erectus had the beginnings of human imagination and being able to envision things in advance, a trait that eventually led to art in their evolutionary descendants. Despite their stone tools’ complexity, there has yet been no evidence that H. erectus used spears.

Perhaps one of the most important factors in H. erectus culture was the use of controlled fire. Being able to produce fire meant that H. erectus could keep wild animals at bay and cook their food. Cooked meat was healthier and far easier to digest. Originally, fire would be an opportunistic find, and the flame would be kept going for as long as possible. Later, the species discovered how to create fire.

The long history of people sitting around the campfire telling stories started with H. erectus, and this practice had a massive effect on the evolution of social capabilities and possibly the complexity of human speech. It is widely accepted that H. erectus was already capable of human speech, much like we are today, but it could also be proposed that increased social activity (such as sitting around a campfire) facilitated the need for complex ideas to be communicated through language.

Evidence for H. erectus art is patchy and subject to much debate. There is evidence that suggests H. erectus made intentional geometric markings on a shell that dates to half a million years ago, and there is also evidence for the use of red ochre, possibly as a decorative device.

An important feature that defines a culture is the level of compassion that individuals are capable of and how they show this. In this, it is abundantly clear that H. erectus is correctly classified in the Homo genus. A very early subspecies of H. erectus, known as Homo erectus georgicus, claims the first hard evidence in the archeological record for human compassion.

In 2002, the toothless skull of an old individual was discovered. The tooth sockets had fused back into the skull, indicating that the individual had lost their teeth many years before they eventually died. It is suggested that this individual was looked after by the group and had their food pre-chewed for them.

The record of Homo erectus ends around 117,000 years ago, and this is likely when the last of them died out, and the species went extinct. By the time of the evolution of Homo sapiens, Homo erectus, which evolved 1.5 million years before, was still walking the earth.

It is theorized that the act of sitting around the campfire in the presence of others generated an evolutionary desire for social interaction and relaxation that included our love for hearing stories and listening to others speak. This, and many other things that make us human today, we owe to Homo erectus, which started on the evolutionary path and developed the traits that would be improved upon in later evolution.

Over the long span of their existence, Homo erectus dominates a great time period in the archeological record of human evolution. Throughout this time, Homo erectus displayed many human firsts that would evolve to be huge parts of what defines us as a species. These things were not just biological adaptations but social and cultural practices that we, as modern humans, engage in every day.