You can reason that they didn't exhaustively search all the area the animals could exist in, so they certainly missed a huge proportion of the total population.

You can reason that they didn't exhaustively search all the area the animals could exist in, so they certainly missed a huge proportion of the total population. It's a tradeoff. They had to kill two animals in order to adequately catalogue and study this species. Just as it would be a tradeoff to decide and take some for captive breeding. Which may also fail.