Humans and gorillas are related, though not in a direct ancestral line where humans evolved from gorillas. Rather, both species share a common ancestor that lived millions of years ago. This shared evolutionary history places them together within the broader family of primates known as great apes.
Unraveling Our Shared Ancestry
Humans and gorillas belong to the Hominidae family, or great apes, which also includes chimpanzees and orangutans. Within this family, humans, chimpanzees, and gorillas are grouped into the Homininae subfamily. This classification signifies a shared evolutionary past, with both descending from a common primate ancestor that existed during the Miocene epoch.
The gorilla lineage diverged from the human and chimpanzee lineage approximately 8 to 10 million years ago, during the late Miocene period. After this divergence, the human and chimpanzee lineages separated much later, around 4 to 7 million years ago. While gorillas are close relatives, chimpanzees and bonobos are genetically even closer to humans.
Unmistakable Biological Connections
The evolutionary relationship between humans and gorillas is supported by biological evidence in genetics and anatomy. Humans share about 98% genetic similarity with gorillas. This reflects a common genetic blueprint inherited from their shared ancestor. While chimpanzees share a slightly higher percentage of DNA with humans (about 98.8% to 99%), the genetic overlap with gorillas remains substantial. About 15% of the human genome resembles the gorilla genome more closely than the chimpanzee genome, highlighting evolutionary complexity.
Beyond genetic similarities, humans and gorillas exhibit anatomical connections, or homologous structures, indicating shared ancestry. Both species possess opposable thumbs and fingernails, adaptations for grasping and manipulation. Their skeletal structures, including hand bones, skull features, and dental patterns, show similarities despite differences in size and function. These shared physical traits reflect a common evolutionary origin, with structures adapting over time to suit different lifestyles.
The fossil record also reveals the shared past of humans and gorillas. While fossil evidence for early chimpanzees and gorillas is relatively scarce, discoveries of ancestral ape forms and early hominins provide data for tracing these evolutionary paths. Fossils like Nakalipithecus and Chororapithecus abyssinicus, dating back 8 to 10 million years, offer insights into the period when the gorilla lineage diverged from the human-chimpanzee line. These finds, combined with genetic analyses, help reconstruct the great ape evolutionary tree.
Diverging Evolutionary Trajectories
Despite their shared ancestry and biological connections, humans and gorillas have followed distinct evolutionary paths. Natural selection and adaptation to varied environments drove these divergences over millions of years.
A primary difference is their locomotion. Humans are characterized by obligate bipedalism, meaning they walk upright on two legs, a trait that developed early in the human lineage. In contrast, gorillas typically engage in knuckle-walking, using the knuckles of their forelimbs to support their upper body weight while moving on all fours.
Brain size and cognitive abilities also diverge. The human brain is larger than a gorilla’s, weighing 1,300 to 1,400 grams compared to 400 to 500 grams. This difference is reflected in the number of neurons, with humans having about 16 billion cortical neurons compared to 9 billion in gorillas. This expanded brain capacity in humans is associated with complex thought, language development, and abstract reasoning. While gorillas demonstrate problem-solving skills, memory, and rudimentary tool use, human cognitive abilities and technological advancements are more extensive.
Tool use and dietary adaptations reflect divergent evolutionary pressures. Humans are known for complex tool manufacturing and use, a driving force in their technological and cultural development. Gorillas, while occasionally observed using simple tools, lack the same sophistication or reliance on technology. Their diets also vary; gorillas are primarily herbivorous, adapted to consuming large quantities of plant matter, while human diets are broader and more varied, enabled by adaptations like smaller teeth and cooking.