Approximately 180,000 chimpanzees (Pan troglodytes) are thought to be left in a long belt of forest stretching from Uganda to the Atlantic from an original population of perhaps 2m. The four races of the animal are all threatened by hunting and habitat destruction.
Our closest animal relative, sharing 98.4 per cent of our DNA, the bonobo or pygmy chimpanzee may the great ape species we lose first. Numbers are thought to be down to around 10,000 in its forest home in the Congo, recently ravaged by war.
There are three races or sub-species of lowland gorilla; their total numbers are probably now less than 110,000.
The most numerous is the western lowland gorilla,(Gorilla gorilla gorilla) found in Cameroon, the Central African Republic, Equatorial Guinea, Congo, and Gabon. It may number about 95,000.
The cross river gorilla (Gorilla gorilla diehli), found in Nigeria and Cameroon, is critically endangered: with numbers of only 150 to 200 it has the lowest population of any of Africa's great apes.
Grauer's gorilla (Gorilla berengei graueri) is found on the eastern side of the Democratic Republic of Congo: there are thought to be about 16,000 left.
Only a few hundred of the mountain gorillas (Gorilla berengei berengei) of the forests of the Virunga volcano region of Uganda, Rwanda and the Democratic Republic of Congo are now left, making them one of the world's rarest animals.
Numbers of Asia's only great ape are now thought to be down to between 15,000 and 20,000, with the Bornean orang-utan (Pongo pygmaeus) numbering 12,000 to 15,000, and the Sumatran orang-utan (Pongo abelli) thought to be between 3,000 and 5,000.
Leakey's idea is to substitute the great apes for the panda as the symbol of conservation. I think it would work. I think an earth where only one great ape (the sapient one) proliferated in increasing numbers without the other four would be a poor place.