Watering The Wildlife

I went to the Denver Zoo Sunday afternoon, a day when the temperature hit 97 degrees.  I was very surprised to see that the zoo waters their wildlife when the temperature gets hot.  I came upon the two zoo employees (at least I assume they are zoo employees) in the photograph on the left hosing off a hippopotamus.

I then walked over to the elephant enclosure, and saw them hosing down the elephant, seen in the photograph on the right.  Since both these animals are native to Central and Southern Africa, and are used to summers on the equator, I would think this wouldn't be necessary, but it evidently is.  Probably something to do with global warming. Since it is necessary here, I assume it is doubly necessary to do this in the wilds of Africa.  A much bigger job out there, and a need for a much much longer hose.