Two strains were developed: the rough- and smooth-coated varieties. The rough-coated beagle survived until the beginning of the 20th century, and there were even records of one making an appearance at a dog show as late as 1969, but this variety is now extinct, having probably been absorbed into the standard beagle bloodline.

In the 1950s, John Paul Scott and John Fuller began a 13-year study of canine behavior. As part of this research, they tested the scenting abilities of various breeds by putting a mouse in a one-acre field and timing how long it took the dogs to find it. The beagles found it in less than a minute, while Fox Terriers took 15 minutes and Scottish Terriers failed to find it at all.

The average size of a beagle litter is six puppies. When mother beagles give birth to litters of puppies, the little pups weigh just a few ounces each.

They are ranked 72nd in Stanley Coren's The Intelligence of Dogs, which places them among the group with the lowest degree of working/obedience intelligence. However, some owners argue that beagles understand what you say--they just don't care as they already have their own agenda.

Due to their size and passive nature, beagles are used in animal testing more than any other dog breed. As many as 65,000 beagles are used every year for medical, cosmetic, beauty, and other chemical tests in the United States alone. The Rescue + Freedom Project (formerly Beagle Freedom Project) has successfully advocated for beagles to be released from labs, freeing hundreds of animals.

Lyndon B. Johnson was a big fan of the breed and had two, named Him and Her, which made frequent appearances whether they were riding along in the president's car, snoozing in the Oval Office, or swimming in the White House pool. After Him was hit and killed by a car while chasing a squirrel, FBI Director J. Edgar Hoover gave the president another beagle named Edgar.

Jonathan Archer took his pet beagle Porthos with him when he took command of the starship Enterprise (NX-01) in 2151. Porthos remained with Archer throughout his entire tenure as Captain of the Enterprise, often going where no dog had gone before.