Robert Sclare, 52, admitted forging applications for special licences to deal in the specimens and illegally keeping the creatures for sale.
Among the species found at his shop in Islington, north London, were a week-old tiger cub, a leopard, a chimpanzee, a green turtle, a grey wolf and 21 birds of prey.
The police raided Sclare's shop in March 1998 after a tip-off from a member of the public to the WWF's Eyes and Ears hotline.
The raid uncovered a total of 69 specimens that were either endangered or protected.
Officers needed two removal vans to take away the items, which also included a black panther, skulls from a gorilla, an elephant's foot fashioned onto a table, some ivory and various big cat rugs and skins.
Investigator from the WWF described the shop as horrific.
'Serious'
Sclare, of Southgate, north London, pleaded guilty at a earlier hearing to 27 counts of forgery relating to permit applications, and 14 of illegally purchasing, selling or displaying the animals for a commercial purpose.
Passing sentence at Snaresbrook Crown Court, Judge Diana Faber said: "When you realise the difficulty you were in you then cobbled together these forged applications to get you out of trouble.
"These are very serious offences, so serious that in fact that nothing but a custodial sentence will suffice."
But the head of the WWF's illegal wildlife trade programme, Stuart Chapman, said his sentence was not long enough.
'Horrors'
"This is an antiquated sentence for what we hope is an antiquated trade," he said.
"The judge and the offender must be living in the past. This sends out the wrong message.
"It doesn't get any worse than this. Entering the shop was like walking into an animal shop of horrors.
"This case shows Sclare's total contempt for the conservation of highly endangered species."
According to the WWF, London is a major centre for the sale of rare wildlife, with many animals smuggled in, dead and sometimes alive, from Europe.
The conservation group estimates that the global, illegal trade in wildlife is worth more than £5bn a year.
Police hope Sclare's prosecution will deter others from profiting from the sale of endangered species.