Ophidiophobes, arachnophobes, herpetophobes, and general zoophobes should steer clear. But if you adore snakes, spiders, reptiles, and amphibians, you've hit pay dirt at this West Berkeley institution. The specialty pet store and de facto zoo peddles a menagerie of nature's most curious and/or intimidating creatures. Seeking a redknee tarantula? A Pancake tortoise? A Hainan cave gecko? There are also slitherers of many types, like Blair's king snakes, cave-dwelling rat snakes, and Borneo blood pythons (shudder!). And check out that Bastimentos dart frog, but don't touch -- this little guy's skin contains batrachotoxin, one of the animal world's most deadly venoms. Vivarium co-owner John Emberton estimates that half of his visitors stop in just to look around. Store regulars bring their newbie friends, and parents come looking for free kiddie entertainment. The staff is cool with all that. "We have school groups and birthday parties coming through, Cub Scout and Girl Scout groups, and they don't buy a thing," Emberton says. "It's free advertising. It's trickle-down. They're not all gonna come back and buy something down the road, but if one in twenty does, then it's worth it." So after your Sunday brunch on yupscale Fourth Street, walk over and view some stuff that would give those soccer moms the creepy-crawlies.