Hippopotamuses are semi-aquatic animals with specialized welfare needs that present unique challenges in captive management. Their welfare science is advancing but lags behind many other zoo megafauna.
Hippopotamuses kept in zoos without adequate aquatic access experience one of the most fundamental deprivations possible for a semi-aquatic species. Their thermoregulation, skin maintenance, and behavioral repertoire are all organized around aquatic habitat. Pools that allow submersion, swimming, and underwater exploration are not enrichment extras but welfare necessities. The social complexity of hippo groups — territorial males, females with calves, juvenile hierarchies — creates management challenges that require sophisticated behavioral assessment and population management planning. Accredited zoos that invest in appropriate aquatic facilities and evidence-based social management provide meaningfully better welfare than those treating hippos as terrestrial animals that happen to like water.