Dogs have lived and worked with humans in many roles. In addition to dogs' role as companion animals, dogs have been bred for herding livestock (collies, sheepdogs), hunting (hounds, pointers), and rodent control (terriers). Other types of working dogs include search and rescue dogs, detection dogs trained to detect illicit drugs or chemical weapons; guard dogs; dogs who assist fishermen with the use of nets; and dogs that pull loads. In 1957, the dog Laika became the first animal to be launched into Earth orbit, aboard the Soviets' Sputnik 2; she died during the flight.
Unlike other domestic species which were primarily selected for production-related traits, dogs were initially selected for their behaviors. In 2016, a study found that there were only 11 fixed genes that 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. Some of these genes have been associated with aggression in some dog breeds, indicating their importance in both the initial domestication and then later in breed formation. 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.
Certain Pacific islands whose maritime settlers did not bring dogs, or where dogs died out after original settlement, notably: the Mariana Islands, Palau, Marshall Islands, Gilbert Islands, New Caledonia, Vanuatu, Tonga, Marquesas, Mangaia in the Cook Islands, Rapa Iti in French Polynesia, Easter Island, Chatham Islands, and Pitcairn Island (settled by the Bounty mutineers, who killed off their dogs in order to escape discovery by passing ships).
Long fur on the paws acts as a trap for grass seeds, grit, or even ice, so regular trimming is advisable. Use a pair of curved scissors with rounded tips. Work on one toe at a time and twirl the fur growing between two toes between your finger and thumb, and then snip the hair off at the base. Be careful never to pull on the fur, which elevates the skin and makes cutting it more likely. If you cannot see where the skin ends and the fur starts, then slide a comb through the fur at skin level, and using the scissors cut on the safe side of the comb. Repeat for each toe on each paw.
Coyotes and big cats have also been known to attack dogs. Leopards in particular are known to have a predilection for dogs, and have been recorded to kill and consume them regardless of their size. Tigers in Manchuria, Indochina, Indonesia, and Malaysia are also reported to kill dogs. Striped hyenas are known to kill dogs in Turkmenistan, India, and the Caucasus.
Dogs demonstrate a theory of mind by engaging in deception. An experimental study showed compelling evidence that Australian dingos can outperform domestic dogs in non-social problem-solving, indicating that domestic dogs may have lost much of their original problem-solving abilities once they joined humans. Another study indicated that after undergoing training to solve a simple manipulation task, dogs that are faced with an insoluble version of the same problem look at the human, while socialized wolves do not. Modern domestic dogs use humans to solve their problems for them.