It hardly seems like a dainty teacup poodle and a wrinkly Neapolitan mastiff could belong to the same species, much less the same subspecies. But both are Canis lupus familiaris , the beloved domestic dog.
A member of the family Canidae — along with wolves, foxes, coyotes and jackals — dogs have been human companions for at least 14, 000 years (and possibly much longer than that). Much about how dogs and humans became inseparable remains the mystery, but research finds that the bond is very real. As many pet owners may already attest, there is evidence that dogs understand human distress and want to help their owners when they’re sad.
Despite the diversity of domestic dogs, these animals share an evolutionary history plus behavioral traits.
When were canines domesticated?
The closest living relative to modern dogs is the gray wolf ( Canis lupus ). The ancestor of modern dogs and the ancestor of recent baby wolves probably split at some point in the late Pleistocene , the last ice age. Genetic studies put different dates on this divided. One 2014 study based on the mutation rates found that this schism happened between 9, 000 and 34, 000 years ago, and that the particular wolf population canines split from later went extinct . Another genetic study (opens in new tab) through 2017 put the window between 20, 000 plus 40, 500 years back.
The oldest fossil that will scientists agree came from a dog, rather than a wolf, comes from a site in Germany called Bonn-Oberkassel and dates back about 14, 200 years (opens in brand new tab) . But archaeologists have found fossil specimens that might be domesticated dogs dating back more than 30, 000 years (opens in new tab) . It’s difficult to confidently identify a Pleistocene fossil fragment as being from either a dog or the wolf, and because canines and wolves interbred even after they diverged genetically, genomic studies are usually complicated. Researchers also debate whether dog domestication occurred once or at multiple sites around the world.
“We don’t know where in the world it happened, ” Anders Bergström, a postdoctoral fellow in ancient genomics at the Francis Crick Institute in London, told Live Science in 2022 . “We how to start what human being group was involved, and we don’t know whether it happened once or multiple times. ”
It is clear that will humankind’s bond with dogs goes way back. The fourteen, 200-year-old canine from Bonn-Oberkassel was buried with two humans plus had been nursed (opens in new tab) through several episodes of canine distemper before it died. In the 12, 000-year-old cemetery within Israel, a woman has been found hidden with her hand on a small wolf or even dog puppy (opens in new tab) . A Stone Age dog from what is now Sweden had been buried with a human companion about 8, 400 years ago, researchers reported in 2020.
What are dog breeds?
In the time since domestication, humans have shaped dogs like clay: Sometimes this appears like the only things different dog breeds have in common are four legs and a tail. The American Kennel Club (AKC) currently recognizes 200 bread of dogs (opens within new tab) , and that list doesn’t even begin to touch the particular diversity of hybrid breeds (Labradoodles, anyone? ) plus uncategorizable mutts (often the best kind).
The AKC isn’t the final arbiter associated with what makes a dog breed. According to the organization, there are some 400 breeds registered all over the world. AKC registration just means there are enough of a certain breed in the United States and enough interest from owners in documenting the breeding history and a “breed standard, ” which is the description of the ideal characteristics of a breed.
Picking dogs with certain characteristics and breeding to maximize those traits has led to canines specialized with regard to many various tasks. Labrador retrievers, for example — which often top the lists of most popular bread of dogs in the usa (opens in brand new tab) — have webbed toes and a two-layered coat that is resistant in order to water. These are qualities left over from the breed’s original role of retrieving downed ducks for duck hunters. Based on the AKC (opens within new tab) , Labradors were bred from your St. John’s canine, a water-loving breed used in early Newfoundland fisheries to retrieve nets plus lines.
The sausage-like dachshund, on the particular other hand, is a poor swimmer yet a keen hunter. It was carefully bred for its narrow body and digging acumen, all the better for burrowing into badger dens plus killing the occupants, according to the AKC (opens in new tab) .
Though most official modern breeds date back to the Victorian era, a 2010 paper (opens in new tab) did find divergence between some breeds indicating that they emerged 500 or more years ago. These breeds were the particular basenji, Afghan hound, Samoyed, saluki, Canaan dog, New Guinea singing dog, dingo (a wild canine), chow, Chinese shar-pei, Akita, Alaskan malamute, Siberian husky and American Eskimo dog.
Do dogs see color? (And other dog senses)
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Canines can see yellow plus green hues , but they can’t distinguish red through green — a similar situation to people who are red-green color-blind. However, dogs might be more sensitive in order to ultraviolet light than humans are, according to 2014 research (opens in new tab) , in which case they would be much better at sensing a wider ranges associated with blues compared to people are.
Dog vision is almost three times blurrier than human vision, based on a 2017 study (opens in new tab) . In that research, whippets, pugs and Shetland sheepdogs were trained with treats to distinguish lines that were different distances from one another. These lines were then used to give the canines a visual test, not unlike the alphabet chart a human might see during a visit to the eye doctor. Dogs had regarding 20/50 eyesight, the study found, meaning that something a human being could notice clearly at a distance of 50 feet (15 meters), a puppy could see clearly at 20 feet (6 m). Dogs, however , do observe better compared to people in dim light, based on the Merck Manual for Veterinary Medicine (opens in brand new tab) , and can notice movement better, too. One special feature that magnifies light in order to a dog’s eye is the tapetum lucidum, a reflective layer that will also gives dogs their characteristic eyeshine at night.
Hearing plus smell are where dogs really shine. According to the Merck Manual, canines hear about 4 times much better than human beings do. Incredibly, their sense of smell is the whopping thousand to ten thousand times much better than ours. The olfactory center of a dog’s brain is 40 times the size of the particular olfactory center in a human’s brain. Because dogs can distinguish between smells with great sensitivity, these people have been trained to sniff out individual diseases: researchers discovered in the early 2000s that dogs can smell out signs of earlier stage cancers , and within 2021 scientists found that canines could determine COVID-19 in the scent of urine samples, Live Science previously reported.
Can dogs feel emotions?
Humans and canines really do realize each other. The 2014 research found that will emotional processing regions of dogs’ brains respond to human emotional sounds , like laughing and crying, in the same way as these regions respond to dog emotional sounds, like whining or yipping. Human beings, too, process dog psychological sounds inside the same way they will process human being emotional sounds.
But what emotions do dogs feel? And exactly what do they understand about others’ feelings?
It’s pretty clear that dogs experience basic emotions, like pleasure, sadness, anxiety and fear, said Julia Meyers-Manor, a psychologist in Ripon College in Wisconsin who research animal feelings. Meyers-Manor led a 2018 study that will found that dogs showed stress in response to their own owners’ crying noises which dogs were a lot more likely in order to attempt to comfort or assist a crying owner compared with the laughing owner. Follow-up research that has not yet been published suggests that canines try to comfort upset strangers, too, though not as readily as they comfort and ease their proprietors, Meyers-Manor informed Live Technology.
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“There’s quite a bit of consistency in brain areas that procedure emotions across mammal species, ” she said. Dogs are social animals, so it’s not surprising that they’d react to the particular emotions associated with others. It really is interesting, nevertheless , that dogs respond to emotions throughout species, the girl said. It’s possible that crying is similar enough among species in order to elicit a response no matter what animal is crying and what animal will be listening, the lady said. It can also possible that, because dogs have co-evolved along with humans regarding so long, they’re particularly good at interpreting human emotion. More study comparing various species’ reactions is needed to clear up these types of questions, Meyers-Manor said.
In spite of these similarities, one thing is certain: Your dog probably doesn’t feel guilt when it digs up the flower beds and knocks over the trash. Although many dog owners take the pitiful, droopy-eyed look a dog gives in order to senses trouble to mean that their dogs know exactly what they did wrong, a 2009 study found the guilty look is simply a way to stay out of trouble. In that study, dogs were put into situations where they were framed for doing something wrong, like eating a forbidden treat. Even when the canines had not eaten the treat, they looked guilty when their owners thought they had and scolded them.
In other words, the particular expression that humans interpret as guilt is nothing from the sort. It’s just a reaction to the scolding human. “They’ve simply learned, make this expression when there’s a big mess in typically the house plus owners won’t kill you, ” Meyers-Manor said.
How smart are dogs?
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Dogs are pretty smart, though not “exceptional, ” according to a new 2018 study in often the journal Learning & Behavior (opens in brand new tab) . The study compared dogs with other carnivores, with some other social hunters, and with additional domesticated animals, looking at definitions of intelligence that covered sensory cognition, physical knowledge, spatial honnêteté, social expérience and self-awareness. These comparisons focused on various other species for which cleverness studies have been conducted, which mainly included wolves, hyenas, African wild dogs, cats , bottlenose dolphins, chimpanzees , horses and pigeons.
On your whole, the exact researchers concluded, dogs have sensory abilities similar to those of different hunting flesh eaters. They’re fairly bad in solving issues involving objects, such as pulling a string to get at some sort of treat attached to the many other end. Spatial cognition, which usually involves understanding places in addition to navigation, was harder to compare, the researchers found, but there did not seem in order to be any evidence that will dogs had been standouts compared with other predators. Dogs have been impressive from using several other animals’ conduct to “cue” their personal and do beat out many other similar animals with social learning, though dolphins and chimps might be better on imitation. Finally, unlike dolphins and chimpanzees, dogs don’t show numerous indications of self-awareness, or the ability to project themselves mentally into the past or future by remembering events like a story or planning for future events.
Dog smarts are about what would be expected from a domesticated social carnivore and hunter, the experts concluded in their paper. Dogs are socially savvy, paying attention to cues from various dogs and even from humans, their evolutionary co-pilots. They have sensory abilities together with spatial smarts sufficient to be able to navigate the environment of a good pack seeker. But they aren’t as good during things that don’t matter as much to their survival, like figuring out how items work or even making detailed plans with regard to the long term.
How do canines help people?
Humans and dogs have been working together for a long time. Though the particular earliest history of dogs is shrouded in mystery, there are usually hints of which humans may have used dogs to help with hunts as long as 14, 000 years back, according for you to a 2019 study in the Journal of Anthropological Archaeology (opens within new tab) . In Saudi Arabia, rock art estimated to be about 8, 000 years old shows people hunting along with dogs on leashes, killing ibex and additionally gazelles, ScienceAlert reported (opens inside new tab) .
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Today, dogs still help sportsman stalk quarry large not to mention small. Labrador retrievers continue to be used to hunt ducks, while sprinters such as typically the Pharaoh hound (opens in new tab) are really excellent for catching prey such as rabbits.
Dogs are also used simply by police and also the military, often to sniff out drugs or perhaps explosives, in order to perform search and rescue operations, and to bite as well as hold suspects. According to be able to the AKC (opens in brand-new tab) , police dogs are usually breeds the fact that have been bred for you to be highly trainable, including German shepherds, Labrador retrievers, and bloodhounds.
Modern puppies also play a huge role because service pups, therapy pet dogs and emotional support animals. Guide Dogs or Seeing Eye Dogs help people together with vision loss navigate obstacles. Therapy dogs are used to support and calm individuals with autism, post-traumatic stress disorder, anxiety and other conditions. There are even squads of good-natured pets roaming airports (opens in new tab) (with their own handlers, associated with course), calming nervous travelers with snuggles.
Check out the Humane Society of America (opens throughout new tab) for more upon pet dog behavior and welfare. The American Kennel Club (opens around new tab) is an exhaustive reference about dog breeds, health, and training. For a deep and comprehensive dive into what scientists know (and don’t) about how dogs were domesticated and came to the Americas, read this 2021 papers ” Dog domestication plus the dual dispersal of people and k-9s into often the Americas (opens in new tab) , ” which is freely available.
Originally published on Live Science.