Monkeys can be caught with a glass jar that has a long neck on it....long enough so that a monkey can't touch the bottom of the jar by reaching down the neck. A delectable monkey-treat --some nuts or a piece of fruit-- is dropped into the jar. It is then placed where a monkey can have access to it, and they will invariably be so engrossed in viewing, and believeing they can reach, the goodie at the bottom, they are often unaware they have been caught until the net is thrown and tied around them. So catches the J-Dub many a new 'brother' or 'sister'. If you think that may be heartless, pity the born-in.
Kudos to all who have had the presence and sense of mind to leave.