In my novel, there is money to made in the capturing and selling of 'exotic' animals from a distant, jungle-covered continent, though for various reasons (notably that it is illegal under Roman rule) buyers often like to keep their purchases and contacts secret. So they hire pirates who sail to these strange lands and capture the unusual animals found there. However, often these animals can be quite enormous (e.g T-rex like creatures, giant anacondas etc) and dangerous.
Obviously the hunters would have to have some kind of tranquilizing methods consistent with a voyage at sea taking potentially days. Issues would include how to get the animal on board, how and where too keep the animal, how to keep it sedated, methods for preventing disaster if sedation failed, and importantly, how to keep it alive.
Any thoughts or suggestions would be welcome!