Mouse Pup Appearance by Age

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Description of Developmental Stages: Birth - Day 14

Age

Description

Day 0

  • Blood red
  • Possible milk spot

Day 1

  • Lighter color red
  • Milk spot present

Day 2

  • Ears appear as nubs
  • Milk spot present

Day 3

  • Ear flap starting to come away from head (one or both)

Day 4

  • Ears fully developed, completely off head, some starting to go towards back
  • Increasing skin color

Day 5

  • Ears are fully back
  • Skin appears much thicker with more color density to skin

Day 6

  • Milk spot is disappearing or gone
  • Colored fuzz appears behind ears or on neck

Day 7

  • Colored fuzz starting to cover pup

Day 8

  • Belly begins to show fur

Day 9

  • Fur is now thicker
  • Females may show nipples (there are five pairs of mammories)

Day 10

  • Fur growth is complete
  • Pups are more active

Day 11

  • Teeth are beginning to erupt
  • Eyes start to open

Day 12

  • Eyes are open
  • Pups begin to nibble solid food

Day 13

  • Pups increase solid food intake

Day 14

  • Pups increase in weight and size, eating more solid food

 

© Jackson Laboratory Mice Pup Appearance by Age