The National Zoo has done wonderful things to cater to children, a natural constituency for a place with lots of animals. There’s a big, soft pizza where kids jump and frolic; there’s farm animals; and there’s Boo at the Zoo, the annual Halloween celebration. Nice as all those things are, the Small Mammal House is where it’s at for kids. This is the spot where the Golden Lion Tamarins run around and where the naked mole-rat follows one tunnel or another. Like a good comedian, these little critters are always “on.” They’re doing stuff, moving their heads, checking stuff out, hopping around, and so on. All that motion is often a great relief after eyeing many of the zoo’s large, slacker animals. Last time I saw a panda at the zoo, it was lying on its side, forever.