Anup Shah / Chimpanzee {Pan troglodytes} grooming companion Sweetwater Sanctuary, Mahesa, Kenya

Anup Shah / Bonnet macaques {Macaca radiata} grooming one another in tree Periyar NP, Kerala, India

Ann & Steve Toon / Bateleur eagle (Terathopius ecaudatus) pair, male (left) and female (right), allogrooming, Kruger National Park, South Africa.

Lucas Bustamante / Toque macaques (Macaca sinica) allogrooming, Yala National Park, Southern Province, Sri Lanka.

Suzi Eszterhas / Grey bamboo lemur (Hapalemur griseus) one grooming another, Madagascar.

Vincent Grafhorst / Meerkat (Suricata suricatta) group allogrooming, Botswana

Vincent Grafhorst / Meerkat (Suricata suricatta) group allogrooming, Botswana

Cyril Ruoso / Alpine Marmot (Marmota marmota) adults allogrooming, looks like one whispering in the other's ear, France

Richard Du Toit / Common Zebra (Equus quagga / burchellii) grooming one another, Gauteng Province, Rietvlei Nature Reserve, South Africa

Bernard Castelein / Khur / Asiatic wild ass (Equus hemionus) two nuzzling each other, Little Rann of Kutch, Gujarat, India

Ann & Steve Toon / Blue duiker (Philantomba / Cephalophus monticola) allogrooming, Mlilwane nature reserve, Swaziland

Pat De La Harpe / Female Impala (Aepyceros melampus) allogrooming in grass, Mala Mala GR, Mpumalanga, South Africa