Leopard frogs

Leopard frogs also called meadow frogs are the archetypal "grass frogs" of North America.They are generally very similar, green with prominent black spotting (though actually more like that of a cheetah than that of a leopard).Once abundant in North America, their population has declined in recent years because of pollution and deforestation. Leopard frogs are often used as environmental indicator species because of their heightened sensitivity to chemical pollutants found in the air and water, and they are commonly used as dissection specimens in biology classrooms. They were subject of some pioneering studies in evolutionary biology in the 20th century, and continue to be of much interest to various disciplines of biology.