• European roe (Capreolus capreolus) are the only ungulates with a latent period of pregnancy. A fertilized egg at the morula stage enters the uterus and quickly reaches the blastocyst stage, but then the embryo develops almost not at all for 4.5–4 months.

European roe deer inhabit and develop on land, outside of bodies of water, and their offspring develop in nests built on the ground or close to it, with nests located directly on the surface of the ground. The species reproduces through live birth, with young being born alive on land, not hatching from eggs or larvae; mating occurs in summer, and embryonic development is delayed by several months. Gestation lasts 5 months, and fawns are typically born in spring, with a litter size of 1 to 3. The female has 1 to 3 offspring and exhibits parental care within the nest on the ground, where only the mother shows care for the young. Sexual reproduction is always accomplished through fertilization, without generation changes; males reach maturity from 1 to 2 years of age, and the reproductive interval is 1 year.