Hippopotamuses are keystone species in African river systems whose welfare is inseparable from the health of the aquatic and terrestrial ecosystems they connect.
Hippo welfare is determined largely by the integrity of the river systems they inhabit. A hippo population in a healthy river with sufficient water, secure grazing access, and low human conflict pressure lives with the territorial conflicts and disease risks that are natural to the species — genuine welfare events, but ones that occur against a background of adequate resource provision. Hippos in degraded river systems — with reduced water, agricultural encroachment on grazing routes, and human conflict — face additional welfare challenges: extreme density at reduced water bodies increases territorial conflict severity, reduced grazing access causes nutritional stress, and retaliatory killing creates direct mortality. River conservation that maintains flow, protects grazing corridors, and reduces human-hippo conflict is simultaneously a conservation and welfare intervention for these ecologically important animals.