de Castro JJ, de Castro M, de Castro JA, and Ruiz Teixidor P. 2019. Hippo cannibalism. Biodiversity Observations 10.14:1-3

Biodiversity Observations is an open access electronic journal published by the Animal Demography Unit at the University of Cape Town. This HTML version of this manuscript is hosted by the Biodiversity and Development Institute. Further details for this manuscript can be found at the journal page, and the manuscript page, along with the original PDF.

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Hippo cannibalism

Julio J. de Castro

34 Hedsor Drive, Harare, Zimbabwe

Mabel de Castro

34 Hedsor Drive, Harare, Zimbabwe

Julio A. de Castro

Plaza de Magallanes, Portal 5, Bajo Izquierda, Santa Cruz de Tenerife, Spain

Patricia Ruiz Teixidor

Calle San Miguel 72, 38001, Santa Cruz de Tenerife, Spain

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Carnivory in the common hippopotamus Hippopotamus amphibius (‘hippo’) was observed in Masuma Dam by Dudley (1993) and by de Castro (2015 and 2016). More recently Dudley et al. (2016) has compiled several observed incidents of carnivory in central, east and southern Africa.

Dudley et al. (2016) argue about the importance of carnivory and particularly the observed cannibalism in the transmission of anthrax among hippo populations.

In 2018-19 Zimbabwe had the lowest rainfall in nearly four decades (The Herald, 2019) and Hwange National Park was no exception, receiving much less than its 576mm yearly average,

During a visit in mid September 2019 the park was very dry and several of the pans were drying or already dry. This situation was also severely affecting some of the dams that require pumped water to keep an acceptable water level. Both Nyamandhlovu and Masuma Dams’ water levels were very low despite efforts to pump water day and night.

Large numbers of animals such as elephants, buffalo, greater kudu and impala were coming to drink daily and water levels were seen declining slowly but steadily on a daily basis, more than previously seen.

The hippo population normally observed at Masuma Dam was estimated at about 16 individuals (de Castro 2015b) and only one was seen at the dam part of the time, apparently commuting between Masuma and Mandavu reservoir, a much larger water body situated 15km away.

While spending an afternoon at Mandavu we noted a dead hippo floating close to the shore opposite to the picnic site. There were a number of crocodiles and a couple of hippos feeding on it (Figs 1 & 2).

It is believed (Dudley, 2018) that hippos are not able to open up a carcass and that they depend on natural fermentation or on other carnivores to do so in order for them to feed. It is likely that the crocodiles had eaten part of the carcass so the hippos were able to feed on it. The hippos were seen pushing the carcass and submerging. They would later emerge chewing and swallowing.

After about one hour the wind started blowing the carcass towards the centre of the lake and the hippos did not pursue it, staying at the opposite shore with their pod. Hippo cannibalism has been reported earlier (Dorward, 2015; Dudley et al., 2016) and the present observation adds Mandavu reservoir to other areas in Africa where this phenomenon has been reported.