at one point, to front financial difficulties and trying to maintain the zoo in its original location in the neighborhood of vila isabel, the baron set up a lottery made up of two dozen animals - and, on july 4th 1892, invited to the event exponents of carioca society of the time. 

at the entrance of the zoo, drummond had animals inside cages that were covered with blankets - visitors to the zoo had to guess which animal was under a blanket and at the end of each day, the secret was unveiled and the winner received a prize.   

this method raised the number of paying visitors to the zoological garden, but the idea was not welcome by official authorities, who deemed it illegal and labeled it 'jogo do bicho' (game of the animal).

curiously, since that date all ticket vendors of unauthorized lotteries in rio de janeiro are called 'bicheiros'.