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July 26, 2026Sources cited
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Dog

The dog is a domesticated mammal and a subspecies of the gray wolf, widely kept as a companion animal and working animal.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

The dog is a domesticated mammal and a subspecies of the gray wolf, widely kept as a companion animal and working animal. Dogs vary greatly in size, appearance, and behaviour, and have been bred for roles such as herding, guarding, hunting, and assistance. Their average lifespan is commonly around 10 to 13 years, though this varies by breed, size, genetics, and care.

Domestication and classification

Dogs are domesticated descendants of gray wolves and are classified as a subspecies, Canis lupus familiaris. Their long association with humans has produced extensive variation in behaviour and appearance.

Breeds and roles

Selective breeding has created a large number of dog breeds for tasks such as herding, hunting, guarding, retrieving, and companionship. Many dogs also serve as service or assistance animals.

Behaviour and communication

Dogs communicate with barking, whining, body posture, facial expression, tail position, and scent. Barking is one of several vocal signals used in social communication and alarm behaviour.

Care, diet, and lifespan

Domestic dogs need appropriate nutrition, exercise, veterinary care, and training. Lifespan varies substantially by breed and body size, but most dogs live roughly 10 to 13 years.

Key facts

  • Dogs are domesticated mammals and a subspecies of the gray wolf.
  • They have been selectively bred into many breeds with wide variation in size, coat, and temperament.
  • Dogs are commonly used as companion animals and in working roles such as herding, guarding, and detection.
  • Average dog lifespan is often reported as 10 to 13 years, with smaller breeds generally living longer than larger breeds.
  • Dogs communicate through body language, vocalization, and scent marking.
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Canadian context

Dogs are common companion animals in Canada and are also used in service, search and rescue, policing, and assistance roles.

Frequently asked questions

How long do dogs live?
Most dogs live about 10 to 13 years on average, but lifespan varies by breed, size, genetics, and health care.
What do dogs eat?
Dogs are omnivores in practice and are commonly fed commercial dog food or balanced home-prepared diets; they need nutritionally complete food rather than a human diet.
Why do dogs bark?
Dogs bark to communicate, often to alert, seek attention, express excitement, or respond to fear, stress, or territorial situations.
How to train a dog?
Dog training commonly uses consistent commands, positive reinforcement, repetition, and early socialization. Short, regular sessions are typically more effective than infrequent long sessions.
Best dog breeds for families?
There is no single best breed, but family-friendly choices often include Labrador Retrievers, Golden Retrievers, Beagles, and Cavalier King Charles Spaniels, depending on household size, activity level, and experience.
Do dogs dream?
Yes. Research indicates dogs experience sleep cycles that include REM sleep, and observable twitching or paddling during sleep is consistent with dreaming.

References

  1. American Kennel Club — https://www.akc.org/expert-advice/health/how-long-do-dogs-live/
    Supports: Average lifespan ranges by size and the relationship between breed size and lifespan.
  2. PetMD — https://www.petmd.com/dog/care/how-long-do-dogs-live
    Supports: General average lifespan of 10–13 years and variation by breed, size, genetics, and care.
  3. American Kennel Club — https://www.akc.org/expert-advice/lifestyle/dog-barking/
    Supports: Common reasons dogs bark, including alerting, excitement, attention-seeking, and fear or stress.
  4. American Kennel Club — https://www.akc.org/expert-advice/training/how-to-train-a-dog/
    Supports: Basic dog training approaches such as positive reinforcement, consistency, and short sessions.
  5. American Kennel Club — https://www.akc.org/expert-advice/lifestyle/best-family-dog-breeds/
    Supports: Examples of breeds commonly recommended for families and factors affecting suitability.
  6. Sleep Foundation — https://www.sleepfoundation.org/animals-and-sleep/do-dogs-dream
    Supports: Dogs enter REM sleep and show behaviours consistent with dreaming.
  7. Encyclopaedia Britannica — https://www.britannica.com/animal/dog
    Supports: Dog classification, domestication from wolves, and general species overview.
  8. American Kennel Club — https://www.akc.org/expert-advice/nutrition/what-can-dogs-eat/
    Supports: General guidance on dog diets and the need for balanced nutrition.