I really feel it is completely unecessary for me to make a joke about this one (although you guys can feel free). The facts provide all the humor needed. From Mid-day.com:

IndiaÂ’s first experiment of desi Viagra on animals is going to be tested on the Bihar tigers following the failure of the authorities of Sanjay Gandhi Zoological Garden to raise the tigersÂ’ libido in its bid to enhance their population in the state.

The zoo authority has decided that homeopathic aphrodisiacs and desi Viagra would be tried on tigers to make them impregnate tigresses.

A spokesman of the Garden said the tigers have become very unromantic. “When a tigress started following a white tiger, he bit the tigress’s right paw. This forced us to decide that the only way to do away with the impotency of male tigers is to administer desi Viagra,” he said.