Overview
The common chimpanzee, the closest living relative of humans (sharing approximately 98.7% of DNA). Included in the database as a reference for brain region comparisons, genetic divergence calculations, and behavioral parallels. Displays complex social behavior, tool use, hunting, and cultural traditions. Brain size averages approximately 400 cc.
Brain Anatomy
Endocast-Based Estimates
Brain region sizes are estimated from endocasts (internal skull casts), not direct brain observation. These are approximations with inherent uncertainty.
| Region | Functional Implications | vs. Modern Human |
|---|---|---|
| Frontal | Moderate frontal development; basic tool use and social cognition | Significantly smaller proportionally; less prefrontal |
| Parietal | Moderate parietal; basic spatial processing | Proportionally smaller; less visuospatial integration |
| Temporal | Moderate temporal; social and auditory processing | Less temporal association cortex |
| Occipital | Large proportional occipital; visual processing prominent | Much larger proportionally; more visually oriented brain |
| Cerebellar | Moderate cerebellum | Similar proportional size |
Tools & Technology
No Tool Associations
No stone tools have been directly associated with this species in the archaeological record.
Diet
Omnivorous; primarily frugivorous; hunts small mammals cooperatively
Genetics & Ancient DNA
| Genome Coverage | 99.00% |
|---|---|
| DNA Source | Complete genome |
| Sequencing Year | |
| mtDNA Available | Yes |
| Nuclear DNA | Yes |
| Divergence Date (molecular clock) | 6.30 MYA (95% CI: 5.10–7.60; 85 studies) |
Molecular clock data from TimeTree 5 (Kumar et al. 2022).
Life History
| Estimated Lifespan | ~45 years |
|---|---|
| Age at Maturity | ~14.0 years |
| Weaning Age | ~4.8 years |
| Interbirth Interval | ~5.0 years |
| Gestation | ~8.0 months |
| Dental Development | Slower M1 eruption than humans |
| Brain Growth | Chimpanzee maternal investment |
| Growth Comparison | Faster somatic maturation than humans |
| Confidence | Measured |
Comparative Anatomy
| Encephalization Quotient | 2.50 |
|---|---|
| Intermembral Index | 106.0 |
| Locomotion | Facultative biped |
| Foramen Magnum | Posterior |
| Precision Grip | Rudimentary |
| Pelvic Shape | Tall narrow |
| Robusticity | Moderate |
| Big Toe | Abducted |
| Thorax | Funnel shaped |
Pan troglodytes comparative: knuckle-walking; occasional biped.
DNA Data
Mitochondrial / Genomic Sequences
| Accession | Type | Length (bp) | Organism |
|---|---|---|---|
| NC_001643 | Complete mitogenome | 16,554 | Pan troglodytes |