European Studbook for Common Hippopotamus - Zoo Ostrava

Plans for future housing of common
hippopotamus in European zoos
As a part of a questionnaire sent to the holders at the beginning of the 2009, I have asked for
their plans for holding the species. Six zoos (Amsterdam, Jerez de la Frontera, Kazan, Kyiv, Paris,
Stuttgart) announced that they plan to stop holding common hippopotamus. Two other zoos
(Knuthenborgh and Randers – both in Denmark) which do not hold common hippopotamus at this
moment are interested in keeping the species in the future. Twelve zoos did not answer the
questionnaire; however, since they cooperate well within the ESB, the current numbers of
hippopotamus in those zoos were included in the following results.
Based on the results of the questionnaire in total, 69 European zoos plan to hold common
hippopotamus in the future and the European population would number more than 190 individuals.
Three zoos plan to keep one adult animal and more than a half of zoos (35) plan to keep two adults
only.
The main problem for the future population seems to be a skewed sex ratio, which could
reach 0.56:1 (males:females) according to the results of the questionnaire. Moreover, fourteen zoos
(20 %) plan to keep one sex only and thus they will not contribute to the reproduction of the
species.
I can conclude that the data received from the questionnaire rises two questions for the
stability of European population of common hippopotamus. First, the number of zoos contributing
the reproduction of the species in the future will decrease. Since the transfers of adults are difficult
and expensive, it can be expected that up to twenty percent of hippopotamus will not reproduce.
Thus, the inbreeding could rise among population. Second, since holders prefer females to males,
some zoos may want to stop reproduction to avoid a problem with placing a surplus male. Solving
these questions would be necessary to stabilize the European common hippopotamus population
means.
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