Rod Williams / Male Red-backed Bearded saki monkey (Chiropotes chiropotes) captive, from Venezuela

Thomas Marent / Red-backed Bearded Saki (Chiropotes chiropotes) feeding on fruit, Rewa River, southern Guyana

Thomas Marent / Red-backed Bearded Saki (Chiropotes chiropotes) feeding on fruit, Rewa River, southern Guyana

Roland Seitre / Black bearded saki (Chiropotes satanas) captive, endemic to Brazil. Critically endangered species.

Roland Seitre / Black bearded saki (Chiropotes satanas) captive, endemic to Brazil. Critically endangered species.

Roland Seitre / Black bearded saki (Chiropotes satanas) captive, endemic to Brazil. Critically endangered species.

Rod Williams / Female Red-backed Bearded saki monkey (Chiropotes chiropotes) captive, from Venezuela

Rod Williams / Black bearded saki monkey {Chiropotes satanas} female, captive, from Brazil and Guyana, critically endangered

Luiz Claudio Marigo / Bearded saki monkey {Chiropotes chiropotes} in rainforest, Amazonia, Brazil

Claus Meyer / Red-backed Saki (Chiropotes satanas satanas), Amazon, Brazil

Claus Meyer / Red-backed Saki (Chiropotes satanas satanas) feeding on forest floor, Amazon, Brazil

Claus Meyer / Red-backed Saki (Chiropotes satanas satanas) calling, Amazon, Brazil

Claus Meyer / Red-backed Saki (Chiropotes satanas satanas) endangered, portrait, Amazon, Brazil

Rob Cousins / Black saki / bearded monkey {Chiropotes satanas} portrait, Brazil, captive, Critically Endangered

Joel Sartore / Photo Ark / Red-backed bearded saki (Chiropotes chiropotes) female sitting and feeding, Omaha's Henry Doorly Zoo and Aquarium, Nebraska. Captive.

Joel Sartore / Photo Ark / Black bearded saki (Chiropotes satanas) female, portrait, Fundacao Jardim Zoologico de Brasilia, Brazil. Captive. Endangered.

Joel Sartore / Photo Ark / Black bearded saki (Chiropotes satanas) female, portrait, Fundacao Jardim Zoologico de Brasilia, Brazil. Captive. Endangered.

Joel Sartore / Photo Ark / Black bearded saki (Chiropotes satanas) female, head portrait, Fundacao Jardim Zoologico de Brasilia, Brazil. Captive. Endangered.

Joel Sartore / Photo Ark / Red-backed saki monkey (Chiropotes chiropotes) eating and looking around. The animal then leaves the frame. Omaha?s Henry Doorly Zoo and Aquarium, Nebraska, USA. Captive.

Joel Sartore / Photo Ark / Red-backed saki monkey (Chiropotes chiropotes) eating using its hands. The animal looks around. Omaha?s Henry Doorly Zoo and Aquarium, Nebraska, USA. Captive.

Sven Zacek / Black woodpecker (Dryocopus martius) excavating nest hole. Valgamaa, Southern Estonia. April.

Kerstin Hinze / Male Black woodpecker (Dryocopus martius) drilling a hole in a tree, hunting for insects, Bavarian Forest National Park, Bavaria, Germany, February.

Bryan and Cherry Alexander / Sundogs (parhelia / parhelai) behind a 'Christmas tree' (valve assembly) in the South Tambey Gas Field, Yamal Peninsula, Siberia, Russia. February 2014.

Bryan and Cherry Alexander / A gas drilling derrick at sunset in the South Tambey Gas Field, Yamal Peninsula, Siberia, Russia. February 2014.

Bryan and Cherry Alexander / A 'Christmas tree' (valve assembly) in front of a gas drilling derrick in the South Tambey Gas Field, Yamal Peninsula, Siberia, Russia. February 2014.

Graham Eaton,Graham Eaton / A land drilling rig with casing prepared, ready to be run in to line the wellbore. Kenya

Steven Kazlowski / Trans-Alaskan Pipeline, with blooming fall tundra colours, that runs from Prudhoe Bay on the Arctic coast to Valdez at the north central coast of Prince William Sound, Alaska, USA

Mike Wilkes / Great spotted woodpecker (Dendrocopos major) pecking at bark, searching for bugs under the bark, Warwickshire, UK

Andy Sands / Acorn weevil (Curculio glandium) drilling hole in developing acorn in which to lay egg, UK, Captive, sequence 1/4

Nigel Cattlin / Winter wheat (Triticum aestivum) seedling roots establishing after direct drilling the crop. Berkshire, England, UK. Pinboard sampled specimens, studio shot.

Kerstin Hinze / Slow motion clip of a male Black woodpecker (Dryocopus martius) drilling a hole in a tree, hunting for insects, Bavarian Forest National Park, Bavaria, Germany, February.

Kerstin Hinze / Slow motion clip of a male Black woodpecker (Dryocopus martius) drilling a hole in a tree, hunting for insects, Bavarian Forest National Park, Bavaria, Germany, February.