Bull mastiff, breed of powerful working dog developed in England in the second half of the 19th cent. It stands from 24 to 27 in. (61–68.6 cm) high at the shoulder and weighs from 100 to 130 l...

Working dog, classification used by breeders and kennel clubs to designate dogs raised by humans to herd cattle and sheep, as draft animals, as message dispatchers in wartime, in police and re...

Great Pyrenees, breed of large working dog whose fossil remains date its existence in Europe from the Bronze Age (1800–1000 B.C.). It stands from 25 to 32 in. (63.5–81.3 cm) high at the should...

Rhodesian ridgeback, sometimes called the African lion hound, breed of large, muscular hound developed in South Africa in the 16th and 17th cent. It stands from 24 to 27 in. (61.0–68.6 cm) hig...

Chow chow, breed of powerful nonsporting dog whose origins are obscure but whose development was accomplished many centuries ago in China. It stands from 18 to 20 in. (45.7–50.8 cm) high at th...

Bat, winged mammal of the order Chiroptera, which includes 900–1,000 species classified in about 200 genera and 17 families. Bats range in size from a wingspread of over 5 ft (150 cm) to a win...