Agamids are a group of about 30 species of rough-scaled gangling lizards that occur only in the Eastern Hemisphere. Most abundant in the tropics and subtropics, they live both in jungles and on sandy deserts. They are Old World counterparts of the New World iguanids. In each family there are species occupying the same sort of habitats and often astonishingly similar in appearance. Iguanids, however, have teeth loosely anchored on the inside of the jaw. These teeth are often replaced. Agamids have stronger teeth permanently anchored on the crest of the jaw, and there teeth are not replaced if lost. The short, fleshy tongues of agamids are smooth. Tongues of iguanids are covered with tiny, soft projections. Both have small, granular scales on the sides of the body and often on back and belly, and both are able to change color. Most grotesque of the agamids is the Australian Thorny Devil. It has larger spines than its counterpart in the Americas, the Horned Lizard, but they are alike in refusing to bite, eating only ants, and living in sandy, semiarid regions. Waterlizards and often seen in zoos, have a low crest on the body. One species reaches a length of three feet an has a high crest on its tail. The Frilled Lizard of Australia has a large, umbrella-like membrane attached around its head. Normally this frill is collapsed and draped along its neck and shoulders, but it can be spread suddenly. with the frill spread and its mouth wide open, this big lizard attempts to intimidate enemies. The Australian Bearded Lizard has a similar, smaller throat fan, True agamids of some s50 species, live in the deserts of Africa, Southwestern Asia, and Southeastern Europe. Moderately large, the tails of some kinds are ringed with short spines. Most agamids are insect eaters, but the spiny tailed agamids eat vegetation. They have broad-crowned rear teeth for chewing, and sharp ratlike front teeth for nipping the tips of growing plants. Toad-headed agamids are burrowers in the desert sands. These dwarfs have long, spineless tails and fringes of scales around their eyes to protect them from sand. Bloodsuckers are tropical tree lizards. Mostly tail and long limbs, these lizards do not suck blood but can change in color from grayish brown to red. When to males fight, for example, the winner turns red while the loser slinks off in its dullest colors. The similar, tree-dwelling, angle-headed agamas live in the jungles from southeastern Asia to Australia. In both kinds the body is flattened from side to side, an adaptation for concealment among the slender branches where they live.