 With the growth of popularity of fox hunting in Britain in the 18th and 19th centuries, terriers were extensively bred to follow the red fox, and also the Eurasian badger, into its burrow, referred to as "terrier work" and "going to ground".The purpose of the terrier is to locate the quarry, and either bark and bolt it free or to a net, or trap or hold it so that it can be dug down to and killed or captured.Working terriers can be no wider than the animal they hunt (chest circumference or "span" less than 35 cm/14in), in order to fit into the burrows and still have room to manoeuver.