Determination of the causes of infanticide in capybara (Hydrochaeris hydrochaeris) groups in captivity

The capybara (Hydrochaeris hydrochaeris) is a wild rodent of great economical interest, which are easily domesticated. Breeding these animals in captivity constitutes a great problem due to the high rate of offspring mortality caused by infanticide. To determine the causes of the infanticides, 64 capybara births were analyzed in order to study the relation of offspring deaths with the lack experience of primiparous females, place of parturition-maternity pen (isolated) vs. reproduction pen (in-group) or familiarity among group members. The hypothesis that primiparous females kill their own offspring was discarded. The data revealed that the infanticides were associated with reproductive groups containing females who have not been together since weaning (unfamiliar females) in spite of living together without apparent conflicts until the occurrence of births, when they killed the companions' offspring. This study revealed that when groups are set up of females that were living together since weaning, there is no need to isolate the females for parturition. (C) 1999 Elsevier Science B.V. All rights reserved.