There is no one answer to this question as it depends on a variety of factors, including the size, distribution, and population of otterhounds, as well as the history and ecology of the otterhound. However, some theories about otterhound rarity include that it may be due to the fact that otters are difficult to capture and keep as pets, that they are not well-adapted to living in cold climates, or that they are not well-known and well-loved in the United States.