A pregnant tiger
The tiger was pregnant from the beginning. Smugglers were initially driven by greed, and the desire to make huge profits. They intended to capture not only the tiger, but also her precious babies, and sell them at an exorbitant price.
The tiger, however, managed to escape in the neighborhood. After recapturing the tiger and tranquilizing him again, they found that its uterus was already empty, probably because it had already given birth to cubs.