After spending a lot of my childhood at a Zoo where my friends father was a vet...and at an animal park...where I became very friendly with the keepers and the circus owners who wintered their animals there.. .I saw a lot of good work you never get to hear about...the Zoo took in pets like snakes large cats etc that would of been put down otherwise...lots of wild animals past throught the gates every day...they had care before being let into the wild again..most weekends we let some animal back into the wild that would of died without the care it got at the Zoo......some had to stay none were put down if they could recover...I was there when a few deer were found on a Country Estate that had died out in their own country...they started a breeding program...and now hundreds of those deer run wild in the mountains again...they would of been lost forever...I've seen bad Zoos in my lifetime...but I've also seen the good other Zoos have done...sometimes the few save the many....I'm sure a lot of animals that now run wild would of been lost forever if not for Zoos...