They can also be socialized to get along well with other pets, but care should be taken with rambunctious pets or cats with claws, as they may injure them. If not properly socialized, Papillons can be distrustful and exhibit aggressive tendencies toward other dogs and people. Papillons may also be very playful and affectionate. Widely known as great companion dogs, they have the spirit and energy to keep up with active families, but can also be calm enough to be happy with sleeping in the arms of an equally affectionate owner. Due to their high energy level, they demand an augmented exercise routine, relative to the average companion breed. Papillons are known as excellent watchdogs, as they will alert their owner to changes in their environment. They may be considered garrulous like many other toy dogs. They can withstand heat, but are more sensitive to cold temperatures because of their single-coated fur, and should not be left outside unattended in cold weather. Toy Fox Terrier.