1,    a,    adults,    animals,    artiodactyl,    Artiodactyla,    captive,    captivity,    dive,    dives,    format,    Highlight,    Hippopotamus,    hippos,    lakes,    laterally,    mammals,    move,    movement,    moves,    outdoors,    outside,    Portraits,    river,    riverhorses,    solo,    submerges,    submerging,    swimming,    swims,