In terrestrial zoology, megafauna (Ancient Greek mégalo "large" + New Latin fauna "animal") are large or giant animals. The most common thresholds used are weight over 40 kilograms (90 lb), over 44 kilograms (100 lb), or over a metric ton 1,000 kilograms (2,205 lb). This includes many species not popularly thought of as overly large, such as white-tailed deer, red kangaroo, and humans. The term is also sometimes applied to animals (usually extinct) of great size relative to a more common or surviving type of the animal, for example the 1 m (3 ft) dragonflies of the Carboniferous period.