Papillons have strong sporting, or chasing instincts, from their Spaniel heritage.
They may chase anything that comes in sight, from birds, squirrels, mice, bees, and other flying insects.
Papillons also do not see the difference between them and other, much bigger, dogs, and as they are very quick moving, they may become prey for any bigger dog.
Papillons are not the kind of a dog to take off- leash while at the park.