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Table 2

Behavioral development in dogs14

Age

Behavioral patterns and relevant stimuli

Potential problems if exposure during relevant period is absent

0–13 days
  • Exposure to handling, especially tactile and thermal stimuli
  • Hyperreactivity
  • Altered sensitivity to touch (consider role for tactile stimuli and attendant neurodevelopment in dogs with docked/bobbed tails and docked ears)
13–20 days
  • Exposure to handling by humans and other dogs
  • Exposure to novel auditory and visual stimuli
  • Concerns with visual and auditory acuity (based on laboratory animals)
3–8 wk
  • Puppies begin to eat semisolid food by ~3 wk and solid food by ~5 wk
  • As the period progresses and puppies become more co-ordinated, they engage in pouncing, rolling, rough and tumble play, mouthing, grabbing, and growling at other puppies or older dogs that play with them
  • Species identification may occur as early as 2.5–3 wk of age. Puppies raised only with cats from 2.5–13 weeks of age do not recognize dogs (consider the concern of raising dogs of one breed with only dogs of that breed, which is a common occurrence in very small breeds)
  •  
  • Heightened reactivity to dogs
  • Heightened reactivity to other species, including humans
  • Lack of inhibition in both arousal levels and behavioral responses to arousal
  • Learn to be calm/settle/relax. Such learning has profound responses for how dogs later handle situations that are potentially anxiety provoking
From 5–7 wk to 12 wk
  • Beginning at ~5 wk, puppies begin to recognize “other” and interact with/seek out other species, including humans. This interaction is more complex than the approaching that they will begin to do at 3 wk of age
  • Maximum distress, as indicated only by vocalization, occurs at the 5th wk of development.
  • At 5 wk, dogs begin to truly hone intraspecific skills
  • Interaction with humans intensifies beginning around >6 wk
  • Housetraining is most successfully learned at ~8.5 wk when there is sufficient cortical development to (1) make an association with preferred substrate; and (2) understand that inhibition of micturition may be desirable. Note that puppies with small bladders and high metabolisms may still need to go out hourly even if they are housetrained.
  • Dogs begin to bark by 4–5 wk and growl shortly thereafter. The amount of vocalization and age of onset is affected by breed.
  • By 7 wk, weaning is normally completed
  • Fear of humans and other species
  • Fear of the approaches of humans
  • Lack of learned inhibition for elimination of feces/urine
  • First true pathological fear responses reliably reported for laboratory animals in genetically susceptible lines
From 10–12 wk to 16–20 wk
  • Intense period of learning how to explore/learn about novel environments. Puppies learn about risk and how to make a mistake successfully.
  • Play becomes rougher/appears to be about successfully making and learning from mistakes
  • Neophobia
  • Lack of plasticity in responses
  • Inappropriate play and lack of play
14–20 wk
  • Dogs not allowed to explore new environments by 14 wk will not voluntarily do so. If forced, they freeze and become extremely distressed
  • Normal marking behaviors may begin to appear as dogs approach sexual maturity
  • Neophobia
  • Profound panic
  • Plasticity of response is characteristic of normal behaviors. Lack of plasticity in response is characteristic of abnormal behaviors