Why can't a rat give birth? - briefly
Only female rats have ovaries and a uterus, which are required for gestation; male rats lack these reproductive organs, so they cannot bear offspring.
Why can't a rat give birth? - in detail
Rats are placental mammals; only the female possesses the anatomical structures required for gestation. The male lacks a uterus, cervix, and associated vasculature, making fetal development impossible. In females, the reproductive cycle proceeds as follows:
- Ovarian follicles mature and release an ovum during estrus.
- The ovum travels through the oviduct where fertilization by sperm occurs.
- The zygote implants into the uterine lining, which thickens under the influence of estrogen and progesterone.
- A placenta forms, providing nutrient exchange and hormonal support.
- Oxytocin triggers uterine contractions at parturition, expelling the litter after a gestation period of roughly 21‑23 days.
Hormonal regulation is essential: luteinizing hormone initiates ovulation; progesterone maintains the uterine environment; prolactin prepares mammary glands for lactation. The male’s endocrine profile does not produce these gestational hormones, and his reproductive anatomy is limited to testes, epididymis, and accessory glands, which generate and deliver sperm but cannot house embryos.
Consequently, a rat of the male sex is biologically incapable of carrying offspring, while the female’s reproductive system is fully equipped for conception, development, and delivery.