Oh, even better than the National Zoo adoption is adopting from WWF (but one can choose based on their own interests - not mine). They are heavily involved with conservation efforts, such as preserving habitats. Habitat loss is one of the main causes for species decline, and think about it...it is mostly human-related. Other factors could be a loss from invasive species...that most likely were introduced from humans. So, either way, we just like screwing it up for creatures other than ourselves.

....and again, what a personal way to teach children about animals and their threats. It must feel good for them to know they are helping the animals they love. There is a more diverse range of animals here, something to suit everyone.

When you adopt an animal through the World Wildlife Fund, you actually get some "stuff" to give along with it! Choose from 80 animals, make a donation, and receive an adoption certificate, a photo, and a plush stuffed animal!
Celebrity supporters of WWF include many that are "hotter than they should be" such as Gisele, Scarlett Johansson, and Orlando Bloom. (via You Too Can Be ‘Hotter Than You Should Be’)

I know a lot of children who should have these, even some adults too