Suckling behavior of pine voles (Microtus pinetorum)

The suckling behavior of some mammals is characterized by preferences for a nterior or posterior nipples and consistent return by individual young to p articular nipples or nipple pairs. Some murid species also display tenaciou s nipple attachment. Pine voles (= woodland voles. Microtus pinetorum) have tenaciously clinging young and 2 pairs of abdominal mammae. We examined wh ether young pine voles preferred particular nipple pairs and whether young on the 2 pairs were differentially groomed or dislodged by their mothers. W e also examined whether young showed fidelity to suckling location. Young p ine voles preferred the hindmost nipples and were dislodged less frequently from those nipples than from the more anterior pair. We found no evidence that mothers differentially groomed young on the 2 pairs. Fidelity to nippl e and nipple pair was greater in small than in large litters, which may ref lect less competition for hind nipples in small litters and the need to con sistently stimulate a nipple to ensure productivity.