Although hippos look quite tranquil lounging together near deep mid - river pools, they are quite territorial and are often very aggressive when surprised or challenged. They are extremely powerful.
Kaut arī nīlzirgu bariņš, kas laiskojas upē dzelmes tuvumā, izskatās diezgan mierīgs, nīlzirgi aizstāv savas teritorijas robežas un bieži uzbrūk, ja ir iztraucēti vai sakaitināti.