---
title: "African grey parrot · Animals and other organisms · Entities · Simulation Hypothesis"
url: https://simulation-hypothesis.com/entities/greyparrot
description: "About 1.6 billion neurons. Decades of laboratory study of numerosity and categorisation."
license: https://creativecommons.org/licenses/by/4.0/
credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)"
---

[Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Birds

# African grey parrot

Psittacus erithacus

About 1.6 billion neurons. Decades of laboratory study of numerosity and categorisation.

Neurons

1.57 billion measured  · whole brain (isotropic fractionator) 

Olkowicz S et al. (2016). Birds have primate-like numbers of neurons in the forebrain. PNAS 113:7255-7260\. doi:10.1073/pnas.1517131113.

In the cerebral cortex (or bird pallium)

about 850 million (pallium, derived from telencephalon counts)

Olkowicz S et al. (2016). Birds have primate-like numbers of neurons in the forebrain. PNAS 113:7255-7260\. doi:10.1073/pnas.1517131113.

## Evidence

* Long-term lab studies of numerical and categorical concepts in a grey parrot.  
Pepperberg IM (1999) The Alex Studies: Cognitive and Communicative Abilities of Grey Parrots. Cambridge, MA: Harvard University Press. doi:10.4159/9780674041998.

The [New York Declaration on Animal Consciousness](https://sites.google.com/nyu.edu/nydeclaration/declaration) (2024) finds strong scientific support for conscious experience in mammals and birds.

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