What do baby mice look like? - briefly
Newborn mice are hairless, pink‑skinned, with closed eyes and ears, and they measure roughly 1–2 cm in length. Within a week they sprout a fine grayish fur and their eyes begin to open.
What do baby mice look like? - in detail
Newborn mice, often called pups, are extremely small, typically measuring 1–1.5 cm in length from nose to tail tip and weighing 0.5–1 g. Their bodies are covered with a fine, almost translucent layer of downy hair that lacks the darker pigmentation seen in adults. The fur is usually a pale gray or pinkish hue, reflecting the limited melanin development at this stage.
Eyes remain closed for the first 10–14 days, rendering the head appear smooth and featureless. Ear pinnae are folded flat against the skull, barely discernible beneath the soft hair. The whiskers are absent or only rudimentary, providing no tactile cues until later growth. The tail is short, roughly one‑third the body length, and is covered by a thin membrane of skin rather than the scaly, hair‑covered structure of mature individuals.
Key physical characteristics by developmental milestone:
- Day 0–3: Closed eyes, sealed ears, pinkish skin, minimal fur, no visible teeth.
- Day 4–7: Ear folds begin to lift slightly; fur becomes denser; pink coloration of the skin persists.
- Day 8–14: Eyes start to open; ear pinnae stand upright; fur darkens gradually; incisors become visible as the pups begin to nibble on the mother’s milk.
- Day 15–21: Tail lengthens and gains the adult’s scaly texture; whiskers emerge; overall coloration approaches that of the adult, typically brown or gray depending on the strain.
Species variations are modest; the common house mouse (Mus musculus) exhibits the described features, while larger rodent species such as the deer mouse (Peromyscus maniculatus) produce pups slightly longer (up to 2 cm) and with a more pronounced gray‑brown coat at birth.
In summary, newborn mice are characterized by minute size, closed eyes, flattened ears, sparse pale fur, a short membranous tail, and a generally pinkish skin tone that darkens as they mature over the first three weeks of life.