A basking heater for an animal, such as a reptile, includes a housing, a heating element within the housing, and an opening in a bottom of the housing, so that the heating element may radiate heat through the opening, and an attachment arrangement. The attachment arrangement can be used to selectively attach the heater to a terrarium. The housing can be made of thermal plastic resin and can include vents for cooling the housing. The housing can have low profile shape. The heater may have multiple power settings.