Relationship of the Estrogen Surge and Multiple Mates to Cub Paternity in the Giant Panda (Ailuropoda melanoleuca): Implications for Optimal Timing of Copulation or Artificial Insemination Short Title: Giant Panda Mating and PaternityHuang et al. Summary Sentence: Successful siring by giant panda males corresponds to the estrogen surge in females; males who mate earlier hold a competitive advantage, but dual paternity also occurs.