three hippos motionless in mud, close-up shot, yellow-billed oxpecker on back, pecking, medium to close-up shot

hippopotamus amphibius hippopotamus hippo oxpecker wildlife conservation tanzania pachyderm mammal southern africa mud parasite herbivore yellowbilled fauna africanus maggot protection peck symbiosis africa ear zimbabwe closeup pinworm dangerous zambia environment unspoiled big lazy frighten buphagus wild birds wilderness fearless safari eye nature massive movenment outdoors water