Reproductive asymmetry and unilateral pregnancy in Chiroptera.

Bats are noteworthy in that anatomical and/or functional asymmetries of the female reproductive organs are far more frequent and profound than recorded for any other mammalian Order, being observed in representatives of all 13 familis so far examined. Asymmetry is expressed as a unilateral dominance of an ovary, the uterus, or both. Dextral dominance is most frequent, but cases of sinistral dominance are recorded. In general 6 basic patterns of asymmetry are recognizable. These are briefly described. Physiological factors which may condition expressions of asymmetry in specific cases are discussed, and some avenues for future research are suggested.