List of Animals by Number of Neurons

Cool. Very significant work by Herculano-Houzel in this field. There are a some nice talks from her on her pioneering approach.

Getting number of neurons is still easier after making assumptions about cell densities across brain regions. The much harder problem is quantifying synapse densities and hence synapse numbers. Especially because they change across age which makes it even more challenging to compare across species that live for different lifespans.