African buffalo wading in the water and drinking as Oxpecker birds fly in to eat ticks from the buffalo in a symbiotic relationship

white rhino rhinoceros africa african wild wading drinking helpful friends mutualistic eat ticks parasites feeding eating pest control symbiont symbiosis mutualism helping friendship pecking day sunny cleaning obligate facultative plucking ticks skin tickbird relationship oxpecker wildlife benefit interaction infested parasite beneficial bird perching symbiotic hot sun waterhole herd late afternoon sunset warm