section_path: Behavior
section_name: Behavior
paragraph_text: Behavior
  
  Dog behavior is the internally coordinated responses (actions or inactions) of the domestic dog (individuals or groups) to internal and external stimuli. Dogs' minds have been shaped by millennia of contact with humans. They have acquired the ability to understand and communicate with humans and are uniquely attuned to human behaviors. Behavioral scientists thought that a set of social-cognitive abilities in domestic dogs that are not possessed by the dog's canine relatives or other highly intelligent mammals, such as great apes, are parallel to children's social-cognitive skills.
  
  Unlike other domestic species selected for production-related traits, dogs were initially selected for their behaviors. In 2016, a study found that only 11 fixed genes showed variation between wolves and dogs. These gene variations were unlikely to have been the result of natural evolution and indicate selection on both morphology and behavior during dog domestication. These genes have been shown to affect the catecholamine synthesis pathway, with the majority of the genes affecting the fight-or-flight response (i.e., selection for tameness) and emotional processing. Dogs generally show reduced fear and aggression compared with wolves, though some of these genes have been associated with aggression in certain dog breeds. Traits of high sociability and lack of fear in dogs may include genetic modifications related to Williams-Beuren syndrome in humans, which cause hypersociability at the expense of problem-solving ability. In a 2023 study of 58 dogs, some dogs classified as attention deficit hyperactivity disorder -like showed lower serotonin and dopamine concentrations. A similar study claims that hyperactivity is more common in male and young dogs. A dog can become aggressive because of trauma or abuse, fear or anxiety, territorial protection, or protecting an item it considers valuable. Acute stress reactions from post-traumatic stress disorder (PTSD) seen in dogs can evolve into chronic stress. Police dogs with PTSD can often refuse to work.
  
  Dogs have a natural instinct called prey drive (the term is chiefly used to describe training dogs ' habits) which can be influenced by breeding. These instincts can drive dogs to consider objects or other animals to be prey or drive possessive behavior. These traits have been enhanced in some breeds so that they may be used to hunt and kill vermin or other pests. Puppies or dogs sometimes bury food underground. One study found that wolves outperformed dogs in finding food caches, likely due to a "difference in motivation" between wolves and dogs. Some puppies and dogs engage in coprophagy out of habit, stress, for attention, or boredom; most of them will not do it later in life. A study hypothesizes that the behavior was inherited from wolves, a behavior likely evolved to lessen the presence of intestinal parasites in dens.
  
  Most dogs can swim. In a study of 412 dogs, around 36.5% of the dogs could not swim; the other 63.5% were able to swim without a trainer in a swimming pool. A study of 55 dogs found a correlation between swimming and 'improvement' of the hip osteoarthritis joint.