Just when you think you're jaded about nature--you've had it with save the whales, protect the wolves, and don't eat veal--along comes science-writer (Natural Acts, 1985) and novelist (The Soul of Viktor Tronko, 1986, etc.) Quammen with his wonderful lust for life--in its more quirky forms--and his observations on the human observers of nature. Not that he doesn't draw the line. The Quammen rule is that anything with more than six legs and two eyes is out, definitely out. So you can imagine what happened when he discovered that the black widow spider in his den had given birth and that his desk was a seething mass of pinheaded babes spinning their first orbs: RAID. Scorpions (""more cluttered with obnoxious useful hardware than a Swiss army knife"") are ghoulishly dispatched in another chapter with vivid descriptions of what a sting feels like. Quammen also provides the incidental intelligence that scorpions ""see"" with their feet, sensing vibrations and noting time-of-arrival differences across their eight spraddled legs. Piranhas and bedbugs, the almost mythical African okapi, orangutans, the archeopteryx, assorted lizards, including the title iguana, are among the other quaint creatures considered in this collection--mostly culled from Quammen's monthly columns in Outside. There are also musings on urban life--the plight of street trees, for example, and a quite delicious dog-hating essay (""The Descent of the Dog""). We are to blame, he says, for their horrendous population explosion (60 million dogs in the US) and for bringing out the worst in them--in particular, the bark. On the other hand, Quammen all but waxes poetic about the honks (and general life-style) of geese. Of the human observers, Quammen has a fine cast of scientists and naturalists fleshed out by old hands like ""Crawfish""--a guide on an Okefenokee trip he took with ""The Red Ace,"" a high-school buddy. This is a particularly personal essay with echoes of the 60's--and tales of youthful bravura--sketched against the wild beauty of the swamp. Altogether, a fine feast to restore natural wonder.