Nat,
wonderful shots and great technique. While I'm not a zoo fan per se, I'm also not a great fan of species extinction and therefore, the better zoos provide a valuable service through their breeding and educational programs. To the extent that they allow us to see (and photograph) animals we might never get a chance to see otherwise, that's also good.

The fact is, they exist. I don't see how taking -- and sharing -- great photos of magnificent animals can be anything but good.

Nice work, Nat.

Jim