What does a field mouse pup look like? - briefly
A newborn field mouse is hairless, pink, with closed eyes, tiny undeveloped ears, and a slender, translucent body. It weighs only a few grams and remains attached to its mother’s fur for warmth.
What does a field mouse pup look like? - in detail
A newly born field mouse is almost hairless, with a pink‑tinged skin that is soft to the touch. The eyes remain closed, and the ears are folded flat against the head. The head is proportionally large, and the limbs are short and underdeveloped, making movement limited to wriggling within the nest.
During the first week, the pup’s body length measures roughly 2–3 cm, and its weight ranges from 0.5 to 1 g. The tail is concealed under the body and lacks any visible fur. The whiskers have not yet emerged, and the nose is a small, moist button.
At around 10–12 days, the eyes begin to open, revealing dark, unpigmented irises that gradually darken. Fine, downy fur starts to appear on the back and sides, initially a pale gray‑brown shade. The ears lift slightly, though they remain relatively small. The tail becomes discernible, covered with sparse, soft hairs.
By three weeks of age, the young mouse exhibits a fuller coat. The dorsal fur adopts the typical brown or gray coloration of the species, often interspersed with lighter speckles. The ventral side turns whitish or pale gray. Fur length reaches about 3–4 mm, providing modest insulation. The ears are fully erect, and the eyes are fully pigmented, allowing clear vision. The tail length approximates the body length, covered with a thin layer of fur and ending in a slightly darker tip.
At four weeks, the pup is weaned and capable of independent foraging. Its body weight increases to 8–12 g, and its size approaches that of an adult, typically 6–9 cm from nose to tail base. The adult coloration pattern is fully established, with a defined dorsal stripe in some species and a relatively hairless, tapered tail.
Developmental milestones
- Day 0–3: Hairless, eyes closed, weight ≤ 1 g.
- Day 4–7: Minimal downy fur appears on the back, still blind.
- Day 10–12: Eyes open, whiskers emerge, fur density increases.
- Day 14–21: Coat color develops, tail becomes visible, mobility improves.
- Day 21–28: Full fur pattern, ear erectness, weaning, independent feeding.
These characteristics provide a precise visual profile of a field mouse at each early life stage, distinguishing it from the fully mature form.