In the wild, Alpine marmots (Marmota marmota) spend most of their time in underground burrows. Thus the observation of reproduction biology during mating season, gestation, and the early juvenile development is extremely challenging. An ultrasonographic follow-up of pregnancies in captive alpine marmots illustrates the characteristic findings of different gestational phases. The first ultrasonographic proof for a pregnancy was detected on day −25 (day 0 defined as partus). At day −18, first heartbeats were visualized, followed by spontaneous fetal movements on day −14. At day −7, the mineralization of the skeletal system was demonstrated. It was possible to evaluate and monitor the integrity of pregnancy. Ultrasonography is a noninvasive, alternative tool to the classical verification of pregnancy in marmots by progesterone measurement from serum samples.