The domestic dog (Canis lupus familiaris or Canis familiaris)[2] is a domesticated canid which has been selectively bred over millennia for various behaviours, sensory capabilities, and physical attributes.[3]
Although initially thought to have originated as an artificial variant of an extant canid species (variously supposed as being the dhole,[4] golden jackal,[5] or gray wolf[6]), extensive genetic studies undertaken during the 2010s indicate that dogs diverged from an extinct wolf-like canid in Eurasia 40,000 years ago.[7] Their long association with humans has led to dogs being uniquely attuned to human behavior[8] and are able to thrive on a starch-rich diet which would be inadequate for other canid species.[9] Dogs are also the oldest domesticated animal. Dog vary widely in shape, size and colours.[10]