Dog
Dog Temporal range: Late Pleistocene (c. 14,000 yrs B.P.) to present [1]
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Domesticated
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Carnivora |
Family: | Canidae |
Genus: | Canis |
Species: | C. familiaris
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Binomial name | |
Canis familiaris | |
Synonyms[3] | |
List
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Dogs are mammals, usually to be kept as pets, or work on farms or for the police. Some dogs are trained to be rescue dogs and join teams such as mountain rescue.[4]

Dogs have been bred by humans from ancestral wolves. They were the first animals to live with humans.[5]
There was a lot of different types among wolves in the Late Pleistocene.[1] The dingo is also a dog, but many dingos have become wild animals again and live in the wild, away from humans (parts of Australia).[6]
Today, some dogs are used as pets, and others are used to help humans do their work. They are popular pets because they are usually playful, friendly, loyal, and listen to humans. Thirty million dogs in the United States have been registered as pets.[7] Dogs eat both meat and vegetables. Often mixed together and sold in stores as dog food.[8] Dogs often have jobs including police dogs, army dogs, assistance dogs, fire dogs, messenger dogs, hunting dogs, herding dogs, or rescue dogs. They are sometimes called "canines" from the Latin word for dog - canis. Wolves are also canines. A baby dog is called a pup or puppy. A dog is called a puppy until it is about one year old.[9]
Dogs are sometimes known as "human's best friend" because they are kept as pets, are usually loyal, and like being around humans. Dogs like to be petted, but only when they can first see the petter's hand before being petted.[10]
August 26 is National Dog Day worldwide.[11] While March 26 is National Puppy Day in the United States.[12]
Appearance and behaviour
[change | change source]Dogs can smell and hear better than humans but cannot see well in color because they are color blind. Due to the structure of the eye, dogs can see better in low light than humans. They also have a larger field of vision.[13]
Like wolves, wild dogs travel in groups called packs. Packs of dogs are listed by rank, and dogs with low rank will submit to other dogs with a higher rank. The highest ranked dog is called the alpha male. A dog in a group helps and cares for others. Pet dogs often view their owner as the alpha male.[14]
Lifespan of dogs
[change | change source]
Different dog breeds have different lifespans. In general, smaller dogs live longer than bigger ones.[15] The size and the breed of the dog change how long the dog lives on average. Breeds such as the Dachshund usually live for fifteen years, Chihuahuas can reach age of twenty. On the other hand, the Great Dane has an average lifespan of six to eight years; some Great Danes have lived for as long as ten years. An American Bulldog lives for around 15 years. Bigger dogs will have smaller lives than smaller dogs because of the pressure on its heart to move around.[16]
Anatomy
[change | change source]Size and skeleton
[change | change source]Dogs come in a wide range of sizes, from very large breeds like the Great Dane weighing 50-79 kg and measuring 71-81 cm, to very small breeds like the Chihuahua weighing 0.5-3 kg and measuring 13-20 cm.[17] Regardless of size, all healthy dogs have a similar bone structure, except for their tails. There are variations in the skeletal structure among different types of dogs.[18] The dog's skeleton is well-suited for running, with neck and back vertebrae having extensions for back muscles, ribs providing space for the heart and lungs, and flexible shoulders.[19] Selective breeding over time has led to larger skeletons in breeds like smaller skeletons in breeds like terriers.[20] Most dogs have 26 vertebrae in their tails, but some naturally have as few as three. The dog's skull has consistent components across breeds but varies in shape.[21]
Dogs and humans
[change | change source]Dogs are often called "man's best friend" because they fit in with human life. Dogs can serve people in many ways. For example, there are guard dogs, hunting dogs, herding dogs, guide dogs for blind people, and police dogs. There are also dogs that are trained to smell for diseases in the human body or to find bombs or illegal drugs. These dogs sometimes help police in airports or other areas. Sniffer dogs (usually beagles) are sometimes trained for this job. Dogs have even been sent by Russians into outer space, a few years before any human being. The first dog sent up was named Laika, but she died within a few hours.[22]
There is much more variety in dogs than in cats. That is mainly because of the way humans have selected and bred dogs for specific jobs and functions. It may also have something to do with the fact that dogs are pack animals, whereas cats are not.[23]
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A search and rescue dog searches for victims in the debris of a collapsed building in Tehran
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Dog herding sheep
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A guide dog
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Many dogs are used for hunting
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Guard dogs in Cameroon
Dog breeds
[change | change source]
- See main article, List of dog breeds.
There are about 555 recognized dog breeds, more than any other mammal. Dogs started to become more diverse during the Victorian era when humans began controlling which dogs were bred.[24] Most breeds come from a small number of original dogs from the last 200 years. Since then, dogs have changed quickly in appearance and have been selectively bred by people.[25] The differences in skull shape, body size, and limb length between breeds are greater than those found in all carnivores combined. These breeds have unique features like body size, skull shape, tail type, fur texture, and color.[26] Humans have bred dogs for specific traits to help with tasks such as guarding, herding, hunting, retrieving, and scent detection. Dogs also show different behaviors like being very social, boldness, and aggression.[27] Today, dogs are found all over the world.[28]
Photo gallery
[change | change source]References
[change | change source]- ↑ 1.0 1.1 Thalmann, Olaf; Perri, Angela R. (2018). "Paleogenomic Inferences of Dog Domestication". In Lindqvist, C.; Rajora, O. (eds.). Paleogenomics. Population Genomics. Springer, Cham. pp. 273–306. doi:10.1007/13836_2018_27. ISBN 978-3-030-04752-8.
- ↑ Linnæus, Carl (1758). Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I (in Latin) (10 ed.). Laurentius Salvius. pp. 38–40. Retrieved 11 February 2017.
- ↑ Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M (eds.). Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 575–577. ISBN 978-0-8018-8221-0. OCLC 62265494. Wilson, Don E.; Reeder, DeeAnn M. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference. JHU Press. pp. 575–577. ISBN 978-0-8018-8221-0.
- ↑ "Dog | History, Domestication, Physical Traits, Breeds, & Facts | Britannica". www.britannica.com. 2024-09-05. Retrieved 2024-09-06.
- ↑ Irving-Pease, Evan K.; Ryan, Hannah; Jamieson, Alexandra; Dimopoulos, Evangelos A.; Larson, Greger; Frantz, Laurent A.F. 2018. Paleogenomics of Animal Domestication. In Lindqvist, C.; Rajora, O. (eds) Paleogenomics. Population Genomics. Springer, Cham. pp. 225–272. doi:10.1007/13836_2018_55. ISBN 978-3-030-04752-8
- ↑ Cairns, Kylie M.; Crowther, Mathew; Letnic, Mike (2023-05-29). "New DNA testing shatters 'wild dog' myth: most dingoes are pure". The Conversation. Retrieved 2024-09-06.
- ↑ Gifford, Clive; Lisa Clayden (2002). Family Flip Quiz Geography. Miles Kelly Publishing. ISBN 978-1-84236-146-7.
- ↑ CVA, Julie Buzby DVM, CAVCA (2023-12-21). "14 Vegetables Dogs Can Eat (And May Just Love)". Dr. Buzby's ToeGrips for Dogs. Retrieved 2024-09-06.
{{cite web}}
: CS1 maint: multiple names: authors list (link) - ↑ "When Does My Puppy Finish Growing? How Long Do Puppies Grow?". American Kennel Club. Retrieved 2021-05-03.
- ↑ Editorial, Chewy (2018-04-05). "Why Your Dog Is Actually Your Best Friend". BeChewy. Retrieved 2024-09-06.
- ↑ National Dog Day | Celebrating Dogs
- ↑ "NATIONAL PUPPY DAY — March 23". 23 March 2023.
- ↑ "How Do Dogs See the World?". www.petmd.com. Retrieved 2024-09-06.
- ↑ Robbins, Nancy (2012-02-14). Domestic Cats: Their History, Breeds and Other Facts. Nancy Robbins. p. 52. ISBN 978-1-4700-7538-5.
- ↑ "Good Dogs Live Longer — ScienceNOW". Archived from the original on 2011-11-29. Retrieved 2011-05-18.
- ↑ "50 Fascinating Facts About Dogs". www.petassure.com. Retrieved 2024-07-14.
- ↑ Byosiere, Sarah-Elizabeth; Chouinard, Philippe A.; Howell, Tiffani J.; Bennett, Pauleen C. (2018-10-01). "What do dogs (Canis familiaris) see? A review of vision in dogs and implications for cognition research". Psychonomic Bulletin & Review. 25 (5): 1798–1813. doi:10.3758/s13423-017-1404-7. ISSN 1531-5320.
- ↑ Nießner, Christine; Denzau, Susanne; Malkemper, Erich Pascal; Gross, Julia Christina; Burda, Hynek; Winklhofer, Michael; Peichl, Leo (2016-02-22). "Cryptochrome 1 in Retinal Cone Photoreceptors Suggests a Novel Functional Role in Mammals". Scientific Reports. 6: 21848. doi:10.1038/srep21848. ISSN 2045-2322. PMC 4761878. PMID 26898837.
- ↑ "Back pain". Elwood vet. Retrieved 2025-05-08.
- ↑ Miller, Paul E.; Murphy, Christopher J. (1995-12-15). "Vision in dogs". Journal of the American Veterinary Medical Association. 207 (12): 1623–1634. doi:10.2460/javma.1995.207.12.1623.
- ↑ DK (2023-07-06). The Dog Encyclopedia: The Definitive Visual Guide. Dorling Kindersley Limited. ISBN 978-0-241-63310-6.
- ↑ "Why Are Dogs Man's Best Friend? The Unbreakable Bond Explained - Vet Advises". 2023-10-08. Retrieved 2024-07-14.
- ↑ "Why are there so many dog breeds but only a few cat breeds?". CORDIS | European Commission. Retrieved 2024-09-06.
- ↑ DK (2023-07-06). The Dog Encyclopedia: The Definitive Visual Guide. Dorling Kindersley Limited. ISBN 978-0-241-63310-6.
- ↑ Pendleton, Amanda L.; Shen, Feichen; Taravella, Angela M.; Emery, Sarah; Veeramah, Krishna R.; Boyko, Adam R.; Kidd, Jeffrey M. (2018-06-28). "Comparison of village dog and wolf genomes highlights the role of the neural crest in dog domestication". BMC biology. 16 (1): 64. doi:10.1186/s12915-018-0535-2. ISSN 1741-7007. PMC 6022502. PMID 29950181.
{{cite journal}}
: CS1 maint: unflagged free DOI (link) - ↑ "Chihuahua dog | Size, Lifespan, Barking, Personality & Origin | Britannica". www.britannica.com. 2025-03-27. Retrieved 2025-05-08.
- ↑ "Great Dane | Size, Lifespan, Temperament & Health Issues | Britannica". www.britannica.com. 2025-05-02. Retrieved 2025-05-08.
- ↑ Parker, Heidi G.; Dreger, Dayna L.; Rimbault, Maud; Davis, Brian W.; Mullen, Alexandra B.; Carpintero-Ramirez, Gretchen; Ostrander, Elaine A. (2017). "Genomic Analyses Reveal the Influence of Geographic Origin, Migration, and Hybridization on Modern Dog Breed Development". Cell Reports. 19 (4): 697–708. doi:10.1016/j.celrep.2017.03.079. PMC 5492993. PMID 28445722.