Swimming is movement by humans or animals in water, usually without artificial assistance. Swimming is an activity that is both useful and recreational for many species. Its primary uses are bathing, cooling, travel, fishing and escape. An individual's ability to swim can be judged by speed or stamina.
Animals with lungs have an easier time floating than those without. Almost all mammals can swim by instinct. Bats, kangaroos, moles and sloths can swim, despite their rather strange shapes. The few exceptions include apes and possibly giraffes. Land birds can swim or float for at least some time. Ostriches, cassowaries and tortoises can swim.
The goal of competitive swimming is to be the fastest to swim at a given distance and drop time. Competitive swimming became popular in the nineteenth century, and comprises 34 individual events - 17 male events and 17 female events. Swimming is a popular event at the Summer Olympic Games, where male and female athletes compete in 13 of the recognized events each. Olympic events are held in a 50 meter pool. Competitive swimming's international governing body is FINA (Fédération Internationale de Natation), the International Swimming Federation.
The four competitive strokes are the butterfly, backstroke, breaststroke, and freestyle (front crawl). While "freestyle" and "front crawl" are often used interchangeably, freestyle is the more common name and is used in most all club-swimming or international competitions. A swimmer may actually swim any stroke or combination of strokes in a freestyle race. Swimmers generally choose to swim front crawl in a freestyle event since it is typically the fastest stroke.