Domestic Long Hair is a coat description, not a breed. The label covers mixed-ancestry cats with medium to long fur, in every color and pattern from tabby and calico to smoke and solid black. Most adults weigh 8 to 15 pounds, though long fur can make a cat look bigger than it is. Some resemble a Maine Coon or Persian without sharing that ancestry.
That variety is the appeal. A cat's size, energy and temperament depend on its own history, so spending time with a cat tells you more than the label does. What these cats share is a coat that tangles without regular brushing, plus moderate to heavy shedding. With basic care, many live 12 to 18 years, which is a long commitment in a city where plenty of people move between rentals.