Most reptiles -- including snakes, lizards and turtles -- don't do well living with other species. While some can cohabit with frogs or salamanders, those creatures are amphibians, not reptiles. The most important factor is the most obvious -- ensure that reptile species won't eat or attack each other. Your pet reptiles must also thrive in the same habitat and similar temperatures. Keep frequent watch on your reptiles so that you can remove aggressors promptly.
Males and Females
With reptiles, it's not just a question of different species peacefully cohabiting. In nature, some male and female reptiles come together only to breed, spending the rest of their lives apart. Putting opposite-sex reptiles together 24-7 can mean trouble -- but so can same-sex cohabitation. Chameleons prefer to live alone, with the male staying with the female only for a short time to mate. If you put two male chameleons together, fighting will likely ensue. Male iguanas might not just attack other males, but also humans. Females of the same lizard species can often live together, as can one male and several females.
Snakes and Lizards
Most snakes should live alone. However, some species can live with other snakes and even certain lizards. Keep in mind that most snakes require a slightly lower temperature to thrive than lizards, which means you must provide different areas of light and heat in your tank or enclosure. Different types of garter snakes can coexist. So can rat snakes. However, it's best to separate the rat snakes when feeding live or dead prey. Rough green snakes can successfully cohabit with anoles.
If you have the climate and the room for outdoor reptile enclosures, you can put compatible species together in large spaces. Bearded dragons can share space with tortoises, as they do in Wisconsin's Lincoln Park Zoo. These reptiles primarily consume a diet of fruit and vegetables, so can share each others' meals. The bearded dragon also requires some insects to munch on once or twice weekly.
Mixing certain lizard species can work if you plan your terrarium or enclosure carefully. Most lizards require a temperature ranging from 85 to 95 degrees Fahrenheit. Terrestrial, or earth-dwelling, lizards can often live with arboreal, or tree-dwelling, species. Given sufficient space, the two types should rarely interact. Consider lizard behavior, and avoid housing dominant lizards with submissive species. Also take diet, adult size and whether the lizard is a desert or tropical species into consideration. Although terrestrial and arboreal types can coexist, that's not true of tropical and desert species. The environment, no matter how well designed, will be inadequate for at least one of them.