Horse
The horse adapted to survive in areas of wide-open terrain with sparse vegetation, surviving in an ecosystem where other large grazing animals, especially ruminants, could not. Horses and other equids are odd-toed ungulates of the order Perissodactyla, a group of mammals that was dominant during the Tertiary period. In the past, this order contained 14 families, but only three—Equidae (the horse and related species), Tapiridae (the tapir), and Rhinocerotidae (the rhinoceroses)—have survived to the present day.
Booidea
The Booidea, also known as booid snakes, are a superfamily of snakes that contains boas (family Boidae) and other closely related boa-like snakes (but not pythons, which are in a separate superfamily called Pythonoidea). As of 2017, Booidea contains 61 species, including the eponymous Neotropical "Boa constrictor", anacondas (genus "Eunectes"), and smaller tree and rainbow boas ("Corallus", "Epicrates", and "Chilabothrus") as well as several genera of booid snakes from various locations around the world: "Candoia" from New Guinea and Melanesia, sand boas ("Eryx") from northeast Africa, the Middle East, and southwestern Asia, "Charina" and "Lichanura" from North America, "Ungaliophis" and "Exiliboa" from Central America, "Acrantophis" and "Sanzinia" from Madagascar, and "Calabaria" from tropical west-central Africa.