Suzi Eszterhas / Polar Bear {Ursus maritimus} 3/4-months cubs peeking over mother who has been anaesthetised by biologists, Wapusk NP, Manitoba, Canada

John Cancalosi / European common toad, males trying to mate with biologists feet {Bufo bufo} Hungary

Eric Baccega / Sand cliff towering above wildlife biologists in boat on Mpassa river, Bateke Plateau National Park, Gabon. 2019.

Eric Baccega / Wildlife biologists from The Aspinall Foundation feeding Western lowland gorilla (Gorilla gorilla gorilla) male silverback aged 37 years. Rescued as an orphan and released into wild in 2013. Reintrodu...

Eric Baccega / Wildlife biologists from The Aspinall Foundation feeding Western lowland gorilla (Gorilla gorilla gorilla) male aged 17 years. Rescued as an orphan and released into wild in 2007. Reintroduction throu...

Eric Baccega / Wildlife biologist from The Aspinall Foundation and director of Beauval Zoo observing Western lowland gorilla (Gorilla gorilla gorilla) male aged 37 years. Rescued as an orphan and reintroduced in 201...

Eric Baccega / Wildlife biologist from The Aspinall Foundation and director of Beauval Zoo observing Western lowland gorilla (Gorilla gorilla gorilla) male aged 37 years. Rescued as an orphan and reintroduced in 201...

Karine Aigner / Biologists sift through Burmese pythons (Python bivittatus) faeces to see what invasive pythons are eating. Florida, USA, July 2018.

Jaymi Heimbuch / Santa Catalina Island Fox (Urocyon littoralis catalinae) biologists, Julie King and Rebekah Rudy, examining fox during vaccination and health check up, Santa Catalina Island, Channel Islands, Californ...

Jaymi Heimbuch / Santa Catalina Island Fox (Urocyon littoralis catalinae) biologists, Julie King and Rebekah Rudy, examining fox during vaccination and health check up, Santa Catalina Island, Channel Islands, Californ...

SCOTLAND: The Big Picture / White-tailed eagle (Haliaeetus albicilla) chick during bird ringing by RSPB biologists on the Isle of Lewis, Outer Hebrides, Scotland, UK, May.

SCOTLAND: The Big Picture / RSPB biologists surveying seabirds, Shiant Isles, Outer Hebrides, Scotland, UK. July, 2018.

SCOTLAND: The Big Picture / RSPB biologists ringing White-tailed eagle (Haliaeetus albicilla) Isle of Lewis, Outer Hebrides, Scotland, UK, May.

SCOTLAND: The Big Picture / White-tailed eagle (Haliaeetus albicilla) chick being ringed by RSPB biologists on the Isle of Lewis, Outer hebrides, Scotland, UK, May.

Jaymi Heimbuch / Marbled Murrelet (Brachyramphus marmoratus) biologists using drone to locate nests, Newport, Oregon

Jaymi Heimbuch / Marbled Murrelet (Brachyramphus marmoratus) biologists using drone to locate nests, Newport, Oregon

Jaymi Heimbuch / Marbled Murrelet (Brachyramphus marmoratus) biologists using drone to locate nests, Newport, Oregon

Naskrecki & Guyton / White-backed vultures (Gyps africanus) feed in a frenzy at a waterbuck carcass (Kobus ellipsiprymnus), Gorongosa National Park, Mozambique. Waterbuck are large animals with tough hides, and in Gorongo...

Karine Aigner / Biologists researching song birds, weighing and banding birds caught in mist nets. Here birds are kept in breathable fabric bags while they are waiting to be examined. Block island, Rhode Island, US...

Jen Guyton / Biologists attaching a solar-powered GPS transmitter between the shoulders of a white-headed vulture (Trigonoceps occipitalis), using Teflon ribbon that fits like a harness across the vulture's chest....

Jen Guyton / Biologist Teague Scott releases a white-backed vulture (Gyps africanus) that has just been fitted with wing tags. Biologists work quickly to minimize the stress that these birds experience during capt...

Jen Guyton / Ayla Kaltenecker releases an African fish eagle (Haliaeetus vocifer) that was captured in a leg-hold trap to be studied by raptor biologists. The researchers took measurements and a blood sample befor...

Sebastian Kennerknecht / Snowy Plover (Charadrius nivosus) nest in restored salt pond with shells laid by biologists to increase camouflage possibilities for adults, Eden Landing Ecological Reserve, Union City, Bay Area, Cali...

Sebastian Kennerknecht / Snowy Plover (Charadrius nivosus) biologists, Karine Tokatlian and Ben Pearl, collecting oystershells to spread in salt pond, which snowy plovers can use for camouflage, Eden Landing Ecological Reserv...

Enrique Lopez-Tapia / Park biologists place a hide to watch a troop of mandrills (Mandrillus sphinx). Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Enrique Lopez-Tapia / Park biologists radio tracking a troop of Mandrills (Mandrillus sphinx) on the map. Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Enrique Lopez-Tapia / Park biologists radio tracking a troop of Mandrills (Mandrillus sphinx) on the map. Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Enrique Lopez-Tapia / Park biologists radio tracking a troop of Mandrills (Mandrillus sphinx) on the map. Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Enrique Lopez-Tapia / Park biologists radio tracking a troop of Mandrills (Mandrillus sphinx) on the map. Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Enrique Lopez-Tapia / Park biologists radio tracking a troop of Mandrills (Mandrillus sphinx) on the map. Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Enrique Lopez-Tapia / Park biologists radio tracking a troop of Mandrills (Mandrillus sphinx) on the map. Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Enrique Lopez-Tapia / Park biologiss radiotracking mandrills (Mandrillus sphinx). Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Enrique Lopez-Tapia / Park biologists radio tracking a troop of Mandrills (Mandrillus sphinx) on the map. Lopé National Park, Ecosystem and Relict Cultural Landscape of Lopé-Okanda UNESCO World Heritage Site, Gabon.

Suzi Eszterhas / Brown-throated Three-toed sloth (Bradypus variegatus) being examined by Rebecca Cliff, Sloth Biologist, prior to putting on a sloth backpack radio collar before release, Aviarios Sloth Sanctuary, Cost...

Suzi Eszterhas / Brown-throated Three-toed sloth (Bradypus variegatus) being examined by Rebecca Cliff, Sloth Biologist, prior to putting on a sloth backpack radio collar before release, Aviarios Sloth Sanctuary, Cost...

Suzi Eszterhas / Brown-throated Three-toed sloth (Bradypus variegatus) being examined by Rebecca Cliff, Sloth Biologist, prior to putting on a sloth backpack radio collar before release, Aviarios Sloth Sanctuary, Cost...

Suzi Eszterhas / Brown-throated Three-toed sloth (Bradypus variegatus) being examined by Rebecca Cliff, Sloth Biologist, prior to putting on a sloth backpack radio collar before release, Aviarios Sloth Sanctuary, Cost...

Suzi Eszterhas / Brown-throated Three-toed sloth (Bradypus variegatus) wearing a sloth backpack radio transmitter being carried by Rebecca Cliff, Sloth Biologist, to a release site, Aviarios Sloth Sanctuary, Costa Ric...

Suzi Eszterhas / Brown-throated Three-toed sloth (Bradypus variegatus) wearing a sloth backpack radio transmitter travelling by boat with Rebecca Cliff, Sloth Biologist, to a release site, Aviarios Sloth Sanctuary, Co...

Suzi Eszterhas / Brown-throated Three-toed sloth (Bradypus variegatus) wearing a sloth backpack radio transmitter travelling by boat with Rebecca Cliff, Sloth Biologist, to a release site, Aviarios Sloth Sanctuary, Co...

Suzi Eszterhas / Rebecca Cliffe, Sloth Biologist, using transmitter to find tagged Brown-throated three-toed sloths and Hoffmann's two-toed sloths in forest canopy, Aviarios Sloth Sanctuary, Costa Rica. November 2014...

Suzi Eszterhas / Rebecca Cliffe, Sloth Biologist, using transmitter to find tagged Brown-throated three-toed sloths and Hoffmann's two-toed sloths in forest canopy, Aviarios Sloth Sanctuary, Costa Rica. November 2014...

SCOTLAND: The Big Picture / Atlantic salmon (Salmo salar) fry and parr, temporarily stunned awaiting measurements to be taken, Cairngorms National Park, Scotland, UK, September 2015.

SCOTLAND: The Big Picture / Collecting eggs from a wild caught Atlantic Salmon (Salmo salar) to spawn fry in controlled conditions, Sandbanks Hatchery, Glenlivet, Moray, Scotland, UK, November 2015.

SCOTLAND: The Big Picture / Spey Fishery Board biologists electrofishing on the river Dulnain to survey Atlantic salmon (Salmo salar) fry and parr, Cairngorms National Park, Scotland, UK, September 2015.

SCOTLAND: The Big Picture / Spey Fishery Board biologists electrofishing on the river Dulnain to survey Atlantic salmon (Salmo salar) fry and parr, Cairngorms National Park, Scotland, UK, September 2015.

SCOTLAND: The Big Picture / Spey Fishery Board biologists electrofishing on the river Dulnain to survey Atlantic salmon (Salmo salar) fry and parr, Cairngorms National Park, Scotland, UK, September 2015.

SCOTLAND: The Big Picture / Biologist washing freshly fertilised Atlantic salmon (Salmo salar) eggs, an important part of the process preventing them from getting smothered, Sandbank Hatchery, Glenlivet, Moray, Scotland, Novembe...

SCOTLAND: The Big Picture / Biologist taking measurements of Atlantic salmon (Salmo salar) in hatchery before release back into the wild, Sandbank Hatchery, Glenlivet, Moray, Scotland, UK, November 2015.

SCOTLAND: The Big Picture / Fertilising freshly collected Atlantic salmon (Salmo salar) eggs with milt from a cock fish, Sandbank Hatchery, Glenlivet, Moray, Scotland, November 2015.

SCOTLAND: The Big Picture / Spey Fishery Board biologists electrofishing on the river Dulnain to survey Atlantic salmon (Salmo salar) fry and parr, Cairngorms National Park, Scotland, UK, September 2015.

SCOTLAND: The Big Picture / Spey Fishery Board biologist measuring Atlantic salmon (Salmo salar), Glenlivet, Moray, Scotland, UK, November 2015.

SCOTLAND: The Big Picture / Spey Fisheries Board biologist releasing Atlantic salmon (Salmo salar) fry back into the river Dulnain after catching them for annual counts and measurements, Cairngorms National Park, Scotland, UK, S...

Laurent Geslin / Biologists from Iberlince Project monitoring Iberian lynx (Lynx pardinus) in Andalusia, south of Spain. December 2015

Laurent Geslin / Biologist from Iberlince Project monitoring Iberian lynx (Lynx pardinus) examining camera trap, Andalusia, south of Spain. December 2015.

Laurent Geslin / Naturalist removing Tengmalm's / Boreal owl (Aegolius funereus) from nest box to be ringed. Jura, Switzerland. April 2015.

SCOTLAND: The Big Picture / Scientist from the Heriot Watt scientific dive team collecting Horse mussel (Modiolus modiolus) samples to assess biodiversity. Within a Marine Protected Area, Shetland, Scotland, UK, September 2012.

SCOTLAND: The Big Picture / Scientist from the Heriot Watt scientific dive team taking samples to assess the biodiversity of a Marine Protected Area, Shetland, Scotland, UK, September 2012.

SCOTLAND: The Big Picture / Scientists from Heriot Watt University measuring Horse mussels (Modiolus modiolus), a priority marine feature. Within a Marine Protected Area, Shetland, Scotland, UK, September 2012.

Suzi Eszterhas / Cotton-top Tamarin (Saguinus oedipus) biologists, Francy Forero and Felix Medina, tracking collared animal, Proyecto Titi, Colombia

Suzi Eszterhas / Cotton-top Tamarin (Saguinus oedipus) biologists, Francy Forero and Felix Medina, tracking collared animal, Proyecto Titi, Colombia

Sebastian Kennerknecht / Snowy Plover (Charadrius nivosus) nest in restored salt pond with shells laid by biologists to increase camouflage possibilities for adults, Eden Landing Ecological Reserve, Union City, Bay Area, Cali...

Sebastian Kennerknecht / Snowy Plover (Charadrius nivosus) biologists, Karine Tokatlian and Ben Pearl, banding chicks, Eden Landing Ecological Reserve, Union City, Bay Area, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Anna Nisi, Justine Alyssa Smith, and Paul Houghtaling, collaring five week old male cub, Santa Cruz Puma Project, Henry Cowell Redwoods State Park, Santa Cruz...

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Paul Houghtaling and Anna Nisi, looking for kittens in den, Santa Cruz Puma Project, Henry Cowell Redwoods State Park, Santa Cruz Mountains, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Paul Houghtaling and Justine Alyssa Smith, using satellite data to determine location of den, Santa Cruz Puma Project, Henry Cowell Redwoods State Park, Santa...

Paul D Stewart / Photograph of Charles Darwin taken by Lock & Whitfield in 1877 and published in' Men of Mark' 1878.

Cyril Ruoso / Lake Titicaca frog (Telmatobius culeus) with biologist Arthuro Nunoz diving underwater with frog, a species threatened by poaching, Lake Titicaca, Bolivia

Cyril Ruoso / Lake Titicaca frog (Telmatobius culeus) with biologist Arthuro Nunoz diving underwater with frog, a species threatened by poaching, Lake Titicaca, Bolivia

Cyril Ruoso / Oregon spotted frog (Rana pretiosa) biologist releasing frog that was raised by inmates as part of Sustainability in Prison program, Washington, USA. September 2012.

Cyril Ruoso / Oregon spotted frog (Rana pretiosa) biologist releasing frog that was raised by inmates as part of Sustainability in Prison program, Washington, USA. September 2012.

Cyril Ruoso / Oregon spotted frog (Rana pretiosa) biologist releasing frog that was raised by inmates as part of sustainability in prison program, Washington, USA. September 2012.

Cyril Ruoso / Oregon spotted frog (Rana pretiosa) biologist Mark Hayes checking on released frogs that were raised by inmates as part of Sustainability in Prison program, Washington, USA. September 2012.

Cyril Ruoso / Oregon spotted frog (Rana pretiosa) biologist Mark Hayes checking on released frogs that were raised by inmates as part of Sustainability in Prison program, Washington, USA. September 2012.

Cyril Ruoso / Inmates of the Cedar Creek Corrections Center and biologists taking photographs of Oregon spotted frog (Rana pretiosa) Prisoners in this facility are raising endangered frogs for release in the wild,...

Cyril Ruoso / Inmates of the Cedar Creek Corrections Center and biologists taking photographs of Oregon spotted frog (Rana pretiosa). Prisoners in this facility are raising endangered frogs for release in the wild,...

Cyril Ruoso / Inmates of the Cedar Creek Corrections Center and biologists taking photographs of Oregon spotted frog (Rana pretiosa).Prisoners in this facility are raising endangered frogs for release in the wild,...

Cyril Ruoso / Biologist Mark Hayes looking at Oregon Spotted Frog (Rana pretiosa) raised by inmates in the Cedar Creek Correction Center. Prisoners in this facility are raising endangered frogs for release in the w...

Cyril Ruoso / Biologist implanting microchip into Oregon Spotted Frog (Rana pretiosa) raised by inmates in the Cedar Creek Correction Center. Prisoners in this facility are raising endangered frogs for release in t...

Cyril Ruoso / Biologist Mark Hayes looking at Oregon Spotted Frog (Rana pretiosa) raised by inmates in the Cedar Creek Correction Center. Prisoners in this facility are raising endangered frogs for release in the w...

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Sean McCain and Dolan Dillon, using telemetry to track male, Santa Cruz Puma Project, Santa Cruz Mountains, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Chris Fust and Justine Alyssa Smith, measuring canine teeth of sub-adult male during collaring, Santa Cruz Puma Project, Santa Cruz, Monterey Bay, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Justine Alyssa Smith and Chris Wilmers, taking blood from sub-adult male for analysis during collaring, Santa Cruz Puma Project, Santa Cruz, Monterey Bay, Cal...

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Max Allen and Paul Houghtaling, placing radio collar on six week old male cub, Santa Cruz Puma Project, Santa Cruz, Monterey Bay, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Max Allen and Paul Houghtaling, placing radio collar on six week old male cub, Santa Cruz Puma Project, Santa Cruz, Monterey Bay, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Max Allen and Paul Houghtaling, placing radio collar on six week old male cub, Santa Cruz Puma Project, Santa Cruz, Monterey Bay, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Max Allen and Paul Houghtaling, placing radio collar on six week old male cub, Santa Cruz Puma Project, Santa Cruz, Monterey Bay, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Max Allen and Paul Houghtaling, placing radio collar on six week old male cub, Santa Cruz Puma Project, Santa Cruz, Monterey Bay, California

Sebastian Kennerknecht / Mountain Lion (Puma concolor) biologists, Max Allen and Chris Fust, looking at satellite tracking data before looking for den, Santa Cruz Puma Project, Santa Cruz, Monterey Bay, California

Jeff Rotman / Biologists from Alaska Fish and Game catch and sample returning Sockeye salmon (Oncorhynchus nerka) Naknek River, Bristol Bay, Alaska, USA, July 2015.

Jeff Rotman / Biologists from Alaska Fish and Game catch and sample returning sockeye salmon. Naknek River, Bristol Bay, Alaska.

Jeff Rotman / Biologists from Alaska Fish and Game catching and sample returning Sockeye salmon (Oncorhynchus nerka) Naknek River, Bristol Bay, Alaska, USA, July.

Cyril Ruoso / Allison Jolly, a primatologist studying Ring-tailed lemurs. Berenty, Madagascar. October 2005.

Cyril Ruoso / Aevar Peterson ringing Black guillemot (Cepphus grylle) Flatey Island, Breidafjordur, Iceland, June 2007. Aevar Peterson has been ringing birds on Flatey Island for 30 years.

Cyril Ruoso / Aevar Peterson ringing Black guillemot (Cepphus grylle) Flatey Island, Breidafjordur, Iceland, June 2007. Aevar Peterson has been ringing birds on Flatey Island for 30 years.

Cyril Ruoso / Ornithologist ringing Northern fulmar (Fulmarus glacialis) Flatey Island, Breidafjordur, Iceland. June 2007.