Infanticide has been reported in a wide range of taxa. Although recent work suggests that infanticide may be present in managed populations of ungulate species, it has not been documented in wild ungulates. Here, I present qualitative evidence of infanticide in a wild ungulate, the hippopotamus (Hippopotamus amphibius) and suggest that infanticide in the hippopotamus may be a strategy by which males increase reproductive success. I present a conceptual model in which infanticide by males occurs within approximately 50 days post parturition and acts as a means to shorten the interbirth interval, particularly when water resources are scarce, and territory takeovers or changes in dominance hierarchy are likely.