Sealyham Terriers are alert, intelligent and independent. Although they are said to be less energetic than other terrier breeds, Sealyham Terriers enjoy dog sports such as agility, earthdog trials, tracking, flyball, and obedience as sport that gives them physical and mental outlets while helping them bond with their families, They are also reported to be good with children; however, as with all dogs, extremely close supervision is needed to prevent accidental injury to the child or dog and to avoid the dog's subsequently developing fear-based defensive aggression.
The Sealyham Terrier was developed between the years 1850 and 1891 by Captain John Edwards at his estate in Wales. Captain Edwards wanted to develop a breed that would do well at hunting small game, such as badgers, otters and foxes. He wanted a breed that could hunt above and underground. To this end, he mated Basset Hounds, Bullterriers, Fox Terriers, the West Highland White Terrier and the Dandie Dinmont Terrier. The Sealyham Terrier is the result of his efforts. The breed was first introduced to the United States in the 1910 and was recognized by the American Kennel Club shortly thereafter in 1911. The breed has always been popular. Today, Sealyham Terriers are most popular in England and South Africa.