In 2001 a fossil skull found in Chad electrified the world's scientific community.
Nicknamed 'Toumai', this creature supposedly lived when the human and chimp lineages allegedly split, making it the oldest human ancestor ever found.
The leader of the team that made the discovery confessed: 'It's a lot of emotion to have in my hand the beginning of the human lineage...I have been looking for this for so long. I knew I would one day find it, so it is a large part of my life.'
But not all scientists accept this conclusion. For instance, Dr Brigitte Senut of the Natural History Museum in Paris dismissed the skull as a mere female Gorilla.
With such conflicting opinions about the same skull, it does make you wonder. Perhaps the skull's discoverer let his emotion and desire for discovery obscure his interpretation of the evidence.