Claus Meyer / Tiger-striped Leaf Frog (Phyllomedusa tomopterna) waving, Amazon rainforest, Brazil

Tui De Roy / Scarlet Macaw (Ara macao) pair perched on tree limb, originally hand raised by the research center, they are now living in the rainforest canopy, Tambopata-Candamo Reserve, Amazon Basin, Peru

Edwin Giesbers / Person using mobile phone to photograp Lemon-yellow tree frog (Hyla savignyi) Cyprus. April.

Suzi Eszterhas / North American beaver (Castor canadensis) kit playing with Willow (Salix sp) at water's edge. Martinez, California, USA. June.

Suzi Eszterhas / Buff-cheeked gibbon (Nomascus gabriellae) looking out from behind tree trunk. Native to Asia. Captive.

Juergen Freund / Margit Cianelli with hand raised Lumholtz tree kangaroo (Dendrolagus lumholtzi) 'Kimberley' and her semi wild son 'Monty' following her into the house after a day out in the forest. Lu...

Claudio Contreras / Devil's Hand Tree (Chiranthodendron pentadactylon) flower, Filo de Caballos, Sierra Madre del Sur, southern Mexico, March

Nick Upton / Researcher labelling collection tube of Siberian flying squirrel (Pteromys volans) droppings. Droppings found below old deciduous tree with suitable nest hole. Muraka Forest Reserve, near Lisaku, Ida...

Christophe Courteau / Mountain gorilla (Gorilla beringei beringei) juvenile, close-up of hand holding onto Eucalyptus tree. Outside of Volcanoes National Park, Rwanda.

Karine Aigner / Map of Kirtland's warbler (Setophaga kirtlandii) nests drawn by researcher, in Jack pine forest habitat. Michigan, USA, July 2017.

Karine Aigner / Researcher pulls back the undergrowth to reveal the ground nest of a Kirtland's warbler (Setophaga kirtlandii) family, Michigan, USA, July 2017.

Karine Aigner / Portrait of a male Kirtland's warbler (Setophaga kirtlandii) held up in scientists hands, in breeding grounds of Jack Pine habitat. Michigan, USA, July 2017.