Photograph by Donna Eaton A hippo peers from a plant-covered
pool in Kenya’s Masai Mara Game Reserve. These massive mammals
keep cool by submerging their massive bodies in African ponds,
rivers, and lakes for up to 16 hours a day. Though they can hold
their breath for perhaps half an hour if necessary, hippos
typically leave the tops of their heads above the surface. At
night hippos leave the water and roam overland to graze. If
caught on land too long during the heat of the day the animals
can dehydrate quickly. Photograph by Craig Arnold A Zambian
hippo sends an aggressive message by displaying sharp canine
teeth that can reach 20 inches (51 centimeters) in length. Bulls
use this open-mouthed “gaping” display while standing face to
face with one another in order to determine which animal is
dominant. Sometimes a show of strength is not enough and the
behavior leads to potentially fatal battles. Hippos are
dangerous to humans as well. Photograph by Amanda Cotton
Manatees cruise slowly in shallow, warm coasta