How does a rat give birth? - briefly
After a gestation of roughly 21–23 days, the female rat expels a litter of altricial pups through the vaginal canal, typically delivering 6–12 offspring per birth. The neonates are born hairless, eyes closed, and rely entirely on the mother for warmth and nutrition.
How does a rat give birth? - in detail
Rats reproduce through a rapid, internal gestation followed by a brief external delivery. After mating, fertilized eggs develop in the uterus for approximately 21‑23 days. During this period, embryos attach to the uterine wall, forming placental connections that supply nutrients and oxygen.
When parturition begins, hormonal signals—primarily a surge in oxytocin and a decline in progesterone—trigger uterine contractions. The cervix dilates, allowing the first pup to be expelled. Each pup is born enclosed in a thin membrane that the mother immediately removes with her forepaws. The sequence proceeds as follows:
- Contraction phase – rhythmic uterine squeezes push the first offspring forward.
- Membrane removal – the mother bites or pulls away the amniotic sac.
- Nipple attachment – the newborn instinctively seeks a nipple for the first suckling.
- Repeat cycle – contractions continue, delivering subsequent pups at intervals of 2–5 minutes.
A typical litter contains 5–12 young, though numbers can vary with species, age, and health of the dam. The entire birth process, from the first contraction to the delivery of the final pup, rarely exceeds one hour. Immediately after delivery, the mother initiates a grooming routine, cleaning each newborn and stimulating respiration. She also arranges the litter in a nest, often constructed from shredded bedding or paper, providing thermal insulation.
Post‑natal care includes frequent nursing, temperature regulation, and protection from predators. The mother’s milk composition changes over the first two weeks, supplying antibodies and essential nutrients required for rapid growth. By the third week, the pups develop fur, open their eyes, and begin exploring the nest, marking the transition from neonatal dependence to weaning.