Bats are weirder than I thought. Specifically, Greater Horseshoe bats.
According to National Geographic News several generations of female greater horseshoe bats mate with the same male:
During their life span, most female greater horseshoe bats (Rhinolophus ferrumequinum) revisit and breed with a specific male, according to a new study.
That means offspring born in different breeding seasons are full siblings. In addition, the researchers believe that daughters follow their mothers to mating sites to breed with the same male.
" … sharing sexual partners strengthens social ties and promotes greater levels of cooperation within the [bat] colony," said Stephen Rossiter, a zoologist at the School of Biological Sciences, Queen Mary, University of London.
"The females are choosing their mates. We still don't know how they do it, how they pass along the information to their daughters, or how they mostly avoid inbreeding," added Rossiter. The zoologist is the lead author of the new study, which is described in tomorrow's issue of the science journal Nature.
Mate sharing among bats can make for some confusing relationships. In several cases genetic tests showed that a female bat and her maternal half-aunt also were half sisters on their father's side.
Between 1991 and 2002, Rossiter and his colleagues caught bats in nets and collected samples of skin from their wings. The scientists were able to analyze 19 different genes in a group of 452 bats, which included mothers, offspring, and potential fathers.
The researchers positively identified the mothers of 371 individual bats and the fathers of 232. The researchers also determined breeding pairs.
Further study showed that specific males and females paired together on multiple occasions more times than would have occurred at random. This finding suggests that mothers and their female offspring are selecting one male and returning to him for subsequent mating.