Stefan Christmann / Emperor penguin (Aptenodytes forsteri) group clambering up slope during journey to bring back food for young. Atka Bay, Antarctica. September.

Anup Shah / Eastern White-bearded Wildebeest (Connochaetes taurinus) herd crossing the Mara River. Maasai Mara National Reserve, Kenya.

Lisa Hoffner / A baby orphan Elephant (Loxodonta africana) leaning against the rump of its friend. David Sheldrick Wildlife Trust Nairobi Elephant Nursery, Kenya, August 2010.

Francisco Marquez / Volunteers holding Greater flamingo (Phoenicopterus ruber) juveniles to be measured during the ringing process, Fuente de Piedra lagoon, Malaga, Spain. August.

Alex Mustard / Tailing nudibranchs (Hypselodoris tryoni) on colourful sponges. This is a common behaviour in this species, where one individual tracks another, also known as queuing or tailgating. It may be relating...

John Cancalosi / People queuing to vote during Kenyan election, near Kitale Kenya, August 8, 2017,

John Cancalosi / People queuing to vote during Kenyan election, near Kitale Kenya, August 8 2017.

Pal Hermansen / Masai people queuing to vote on election day, Kenya, March 2013.

Merryn Thomas / People queuing for the Passenger Ferry "Voyager of St. Martin's" arriving at Lower Town Quay in the early morning. St. Martin's, Isles of Scilly, UK

Ron O'Connor / White Backed Vultures (Gyps africanus) queuing up to feed on giraffe carcass, Namibia

Denis-Huot / Herd of Common elands (Taurotragus oryx) walking across salt pan. Amboseli National Park, Kenya.

Charlie Hamilton-James / Black rat (Rattus rattus) sitting outside entrance to temple with queue of visitors watching in background, Karni Mata Temple (The Temple of Rats), a Hindu temple dedicated to the Hindu Goddess Karni...