The cattle egret will find other partners if there are no cattle around. They can fly, after all! In the Addo zebra will do.
These birds remove ticks from their grazing mammal friends and are therefore welcome. As wading birds they occur in wetlands and at the seaside, but at least seasonally also in dry and open habitats like grasslands, pastures, farmlands and rice paddies. Egrets sometimes migrate; they have increased their presence over much of the farmed regions on earth. This was easy for a bird with few predators and a predilection for land adapted by farming.
But egrets do not eat grass! So, buddies but not grazing buddies. Their diet consists mainly of grasshoppers, caterpillars and earthworms. Their food lives in the grass, but the grass itself is a zebra matter. Ticks off the body of the zebra they do take occasionally as well as a free ride, hence the companionship. Egrets are also said to contribute to the spreading of tick-borne animal diseases.
The zebra mainly grazes but will browse when opportunities arise. In the Addo Elephant National Park both options are freely available. More than fifty species of grass are recorded as part of typical zebra diet; but move the zebra to new grassy regions and the list will grow.
Zebras are not ruminants like cattle that have four-chamber stomachs for digesting the grass they eat. The zebra has one stomach chamber, as well as a “blind gut” or caecum further on in its alimentary canal, where the small and large intestines meet. This is where zebras digest their grass cellulose, i.e. have it broken down by bacteria. These dedicated bacteria live in a few litres of digestive juices stored here in the caecum for this purpose.
Zebra bodies appear well-rounded all year round. They bulge from the well-fed, internal factory workers that process grass on a lifelong basis in their very private, juicy swimming pool.
It takes all types to populate the land of the living (Riëtte, 2016; Maclean, 1993; Wikipedia).