Rabbits do have umbilical cords. As placental mammals, the developing rabbit fetus, known as a kit, relies on this temporary organ for survival inside the mother’s womb. The umbilical cord is the physical connection that links the kit to the placenta, an organ responsible for all metabolic exchange with the mother. This structure is a fundamental aspect of their reproductive biology, similar to nearly all other mammals.
Umbilical Cord Function During Gestation
The umbilical cord and placenta are necessary for maintaining the developing kits throughout the roughly 31-day gestation period. Fetal blood reaches the placenta through two umbilical arteries, branching into a capillary network inside the organ. This network facilitates the transfer of substances without directly mixing the mother’s and the kits’ bloodstreams. The umbilical vein carries oxygenated blood rich with nutrients, such as glucose and amino acids, back to the developing fetus. Simultaneously, the two umbilical arteries carry deoxygenated blood and metabolic waste, like carbon dioxide and urea, away from the kit for disposal into the mother’s system. This counter-flow mechanism optimizes feto-maternal exchanges. The rabbit’s placenta is classified as hemochorial, meaning the fetal tissue comes into direct contact with the maternal blood, a structure resembling that of the human placenta.
Kindling and Post-Birth Cord Management
The process of a rabbit giving birth is called kindling. The mother rabbit, or doe, instinctually manages the birth of her kits and the subsequent afterbirth. The doe severs the umbilical cord herself by biting through it after the kit is born. The umbilical cord is relatively short, around two centimeters long in a near-term fetus, and contains two umbilical arteries and one umbilical vein.
Once the cord is severed, the doe typically engages in placentophagy, the act of consuming the placenta and often the remnants of the umbilical cord. This behavior is seen in many placental mammals and serves several biological purposes. Consuming the afterbirth helps to return lost nutrients and hormones to the mother following the energetic demands of kindling. Furthermore, eating the placenta and cord removes any evidence of the birth from the nest. This instinctive behavior is intended to protect the vulnerable kits from attracting predators, ensuring the nest remains clean.