Cross-Species Brain Comparison
Estimated brain region proportions across hominin species, based on endocast studies.
Endocast-Based Estimates
All brain region proportions are estimated from endocasts (internal casts of the braincase) and published neuroimaging data. These are approximations with inherent uncertainty. Direct brain tissue is not preserved in the fossil record.
Brain Volume Timeline
Regional Proportions
Species Brain Data
| Species | Brain Volume (cc) | Key Features |
|---|---|---|
| Australopithecus prometheus | 428–510 | Most prominent region: (prominence: 0) |
| Australopithecus africanus | 400–560 | Most prominent region: Occipital (prominence: 6.0) |
| Homo habilis | 550–700 | Most prominent region: Broca Area (prominence: 7.0) |
| Homo erectus | 900–1100 | Most prominent region: Broca Area (prominence: 7.5) |
| Homo heidelbergensis | 1100–1400 | Most prominent region: Frontal (prominence: 8.0) |
| Homo cepranensis | 1165–1185 | Most prominent region: (prominence: 0) |
| Homo neanderthalensis | 1200–1750 | Most prominent region: Frontal (prominence: 7.5) |
| Homo sapiens | 1100–1600 | Most prominent region: Prefrontal (prominence: 9.5) |
| Homo helmei | 1280–1400 | Most prominent region: (prominence: 0) |
| Homo sapiens idaltu | 1450–1450 | Most prominent region: (prominence: 0) |
| Homo floresiensis | 380–430 | Most prominent region: Frontal (prominence: 7.0) |
Encephalization Quotient
Brain-to-body mass ratio standardized across species. Higher EQ indicates relatively larger brain for body size. See full comparative anatomy →
| Species | EQ | Locomotion |
|---|---|---|
| Homo sapiens | 6.20 | Striding biped |
| Homo sapiens idaltu | 5.30 | Striding biped |
| Homo neanderthalensis | 5.10 | Striding biped |
| Homo helmei | 4.80 | Striding biped |
| Homo longi | 4.20 | Striding biped |
| Homo cepranensis | 4.00 | Striding biped |
| Homo antecessor | 3.90 | Striding biped |
| Homo erectus | 3.80 | Striding biped |
| Homo ergaster | 3.50 | Striding biped |
| Sahelanthropus tchadensis | 3.40 | Facultative biped |
| Homo rudolfensis | 3.20 | Obligate biped |
| Homo floresiensis | 3.10 | Obligate biped |
| Australopithecus sediba | 2.85 | Obligate biped |
| Homo denisova | 2.80 | Striding biped |
| Homo naledi | 2.75 | Obligate biped |
| Australopithecus africanus | 2.65 | Obligate biped |
| Australopithecus anamensis | 2.55 | Obligate biped |
| Australopithecus afarensis | 2.50 | Obligate biped |
| Australopithecus prometheus | 2.50 | Facultative biped |
| Ardipithecus ramidus | 2.40 | Facultative biped |
| Paranthropus robustus | 2.35 | Obligate biped |
| Paranthropus boisei | 2.30 | Obligate biped |
| Paranthropus aethiopicus | 2.20 | Obligate biped |