Entities › Animals and other organisms › Mammals

Human

Homo sapiens

86 billion neurons, 16 billion of them in the cerebral cortex. We're the only species whose members can give verbal reports of their experience.

Neurons: 86.1 billion measured · whole brain (isotropic fractionator, 4 male brains)
Azevedo FAC et al. (2009). Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled-up primate brain. J Comp Neurol 513:532-541. doi:10.1002/cne.21974.
In the cerebral cortex (or bird pallium): 16.3 billion
Azevedo et al. 2009 (16.34 B cortex; value confirmed in Olkowicz 2016 supplement).

Evidence

Verbal report is the reference standard for consciousness. The New York Declaration (2024) restates the case for animals.

The New York Declaration on Animal Consciousness (2024) finds strong scientific support for conscious experience in mammals and birds.

In the trees