Milan Radisics / Aerial shot of steam geysers at Gunnhuver Hot Springs, Reykjanes Peninsula, Iceland, August 2018.

Milan Radisics / Aerial shot of steam geysers at Gunnhuver Hot Springs, Reykjanes Peninsula, Iceland, August 2018.

Milan Radisics / Aerial shot of Gunnuhver steam geyser, Gunnhuver Hot Springs, Reykjanes Peninsula, Iceland, August 2018.

Milan Radisics / Aerial shot of Gunnuhver steam geyser, Gunnhuver Hot Springs, Reykjanes Peninsula, Iceland, August 2018.

Steven David Miller / A Perentie (Varanus giganteus) using its forked tongue to detect smells, Alice Springs Reptile Centre, Northern Territory, Australia, Captive. May.

Jeff Foott / Morning Glory Pool, Upper Geyser Basin, Yellowstone National Park, Wyoming

Shane P. White / Japanese Macaque (Macaca fuscata) in hot spring, Jigokudani, Nagano, Japan

David Fleetham / Florida manatee (Trichechus manatus latirostris) at Three Sisters Spring in Crystal River, Florida, USA.

Alex Mustard / Suwanee freshwater turtle (Pseudemys concinna suwanniensis) swimming beneath trees in a freshwater spring. Devil Spring, Ginnie Springs, High Springs, Florida, USA

Jami Tarris / Japanese Macaque (Macaca fuscata) in hot spring, Jigokudani, Nagano, Japan

Michel Roggo / Freshwater spring in the intertidal zone of the Piccaninnie Ponds Conservation Park, South Australia, Australia. March 2015 . Photographed for The Freshwater Project

Hiroya Minakuchi / Japanese Macaque (Macaca fuscata) young in hot spring, Jigokudani, Japan

Juergen Freund / Banded archerfish (Toxotes jaculatrix) spitting, Oolioo Sandbar, Territory Wildlife Park, Berry Springs, Northern Territory, Australia.

Paul Williams / View from plane of landscape between Alice Springs and Perth, Australia, November.

Thomas Marent / Japanese Macaque (Macaca fuscata) mother and young in hot spring with juveniles grooming, Jigokudani, Nagano, Japan

Floris van Breugel / A hot spring in the West Thumb Geyser Basin, Yellowstone National Park, Wyoming. The colors are a result of thermophilic bacteria living in the hot springs. December 2010.

Anup Shah / Japanese Macaque (Macaca fuscata) baby sitting on the edge of thermal hotspring pool. Jigokudani Yean-Koen National Park, Japan, February.

Franco Banfi / Aquatic plants growing on bottom of the main spring at Rio Sucuri, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga fish (Brycon hilarii) split level, in the main spring at Rio Sucuri, Bonito, Mato Grosso do Sul, Brazil.

Fiona Rogers / Japanese Macaque (Macaca fuscata) pair grooming in a geothermal spring, Jigokudani Monkey Park, Japan

Fiona Rogers / Japanese Macaque (Macaca fuscata) baby in a geothermal spring, Jigokudani Monkey Park, Japan

Fiona Rogers / Japanese Macaque (Macaca fuscata) baby sucking its toe in a geothermal spring, Jigokudani Monkey Park, Japan

Kirkendall-Spring / Travertine limestone terraces of Mammoth Hot Springs in Yellowstone National Park, Wyoming, USA, June 2013.

Diane McAllister / Japanese Macaque (Macaca fuscata) adult with wet snowy head in the hot springs of Jigokudani, Japan.

Diane McAllister / Japanese Macaque (Macaca fuscata) adult in the hot springs of Jigokudani, in the snow, Japan. February

Ben Cranke,Ben Cranke / Japanese Macaques (Macaca fuscatata) grooming in hot springs, Jigokudani, Nagano Prefecture, Honshu, Japan

Diane McAllister,Diane McAllister / Japanese Macaque (Macaca fuscata) juvenile approaches the hot springs and feeding area covered in icy snow from the cold night before in Jigokudani, Japan, January

Diane McAllister,Diane McAllister / Japanese Macaque (Macaca fuscata) with icy strands of fur on its head, Jigokudani, Japan, February

Diane McAllister,Diane McAllister / Japanese Macaque (Macaca fuscata) females gather at one end of the hot springs, Jigokudani, Japan, February

Denis-Huot,Denis-Huot / Hippopotamus (Hippopotamus amphibius) underwater, Mzima Springs, Tsavo West national park, Kenya. Vulnerable species.

Jeff Vanuga / Aerial view of Grand Prismatic Springs Midway Geyser Basin. Yellowstone National Park, Wyoming, July 2011.

Erlend Haarberg / Blahver hot spring and Eyvindarhver fumarole, Hveravellir, Iceland, May 2010

Willem Kolvoort / Underwater freshwater springs in the River Black Drim, Albania, Eastern Europe, May 2009

Inaki Relanzon / Springs and waterfalls of Yaga River, in the Escuain Canyon and Valley. Ordesa National Park, Pyrenees, Spain, June 2011.

Charlie Summers / Mustang (Equus caballus) herd trotting in light snow covered prairie, IRAM Wild Horse Sanctuary south of Hot Springs, South Dakota, USA, May

Charlie Summers / Three Western Black-tailed Prairie Dogs (Cynomys ludovicianus) at entrance to burrow. Cheyenne River drainage south of Hot Springs, South Dakota, USA

Chadden Hunter / Dallol hot springs where water heated by magma laden with potassium, sulphur and iron spews up through salt pans staining the salt deposits with vivid colours, in the bottom of the Rift Valley, 120 me...

Wild Wonders of Europe / Geidemark / Syri i Kalter (The Blue Eye) spring, Albania, June 2009

Wild Wonders of Europe / Biancarelli / Crna Rijeka Black river springs, Plitvice Lakes National Park, Croatia, October 2008

Wild Wonders of Europe / Biancarelli / Water flowing round moss covered stones in the Crna Rijeka, Black river springs, Plitvice Lakes National Park, Croatia, October 2008

Wild Wonders of Europe / Biancarelli / Fallen branch and moss covered rocks, Black River Crna Rijeka springs, Plitvice Lakes NP Croatia, October 2008

Stephen Belcher / Japanese Macaque (Macaca fuscata) young embracing at edge of hot spring, Jigokudani, Joshinetsu Kogen National Park, Japan

Wild Wonders of Europe / O Haarberg / Hot springs with sulpur deposits, Leirhnjkur, Iceland, July 2008

Orsolya Haarberg / Steam vents and sulphur deposit at Hverir. Nmafjall, Iceland. June 2008

Orsolya Haarberg / Steam vent at Hverir. Nmafjall, Iceland. June 2008

Yva Momatiuk & John Eastcott / Great Fountain Geyser erupting, Yellowstone National Park, Wyoming

Steven David Miller / Large solar panels for generating electricity by solar power, Hermannsburg, west of Alice Springs, Northern Territory, Australia, August 2007

Steven David Miller / Large solar panels for generating electricity by solar power, Hermannsburg, west of Alice Springs, Northern Territory, Australia, August 2007

Jasper Doest / Japanese Macaque (Macaca fuscata) pair grooming in hot spring, Jigokudani, Japan

Jasper Doest / Japanese Macaque (Macaca fuscata) pair grooming in hot spring, Jigokudani, Japan

Yukihiro Fukuda / Japanese macaque / Snow monkey {Macaca fuscata} 7-month-old monkey bathing in hot springs, examining its hands, water at 40 degrees, Jigokudani, Nagano, Japan

Yukihiro Fukuda / Japanese macaque / Snow monkey {Macaca fuscata} adult female bathing in hot springs tapping the water surface with hand in play, water at 40 degrees, Jigokudani, Nagano, Japan

Yukihiro Fukuda / Japanese macaque / Snow monkey {Macaca fuscata} group of monkeys bathing in hot springs, water at 40 degrees, Jigokudani, Nagano, Japan

Pete Oxford / Dead trees in Mammoth Hot Springs travertine terraces, Yellowstone National Park, Wyoming

LYNN M. STONE / Domestic Chicken, baby chick {Gallus gallus domesticus} USA

John Downer / Hippopotamus {Hippopotamus amphibius} swimming underwater, Mzima springs, Kenya

Juergen Freund / Split level view of river Basslets (Grammidae) in freshwater spring, Florida, USA

Peter Scoones / American alligator underwater (alligator mississippiensis) Silver Springs, Florida, USA captive

Luiz Claudio Marigo / Courtship display of Ostrich pair {Struthio camelus} Buffalo Springs NR, Kenya

Doug Allan / Hippopotamus swimming underwater, Mzima Springs, Kenya, Africa

Peter Scoones / American alligator underwater (alligator mississippiensis) Florida

Anup Shah / Gerenuk standing grazing on Acacia tree {Litocranius walleri} Buffalo Springs, Kenya

Ingo Arndt / Japanese macaques grooming in hot thermal spring {Macaca fuscata} Joshin-etsu NP, Japan. These primates can survive winter temperatures below -15 degrees by bathing in the springs

Tom Vezo / Red-tailed Hawk (Buteo jamaicensis) adult rufous morph flying, Sulphur Springs Valley, Arizona

Konrad Wothe / Japanese Macaque (Macaca fuscata) baby playing with snowball beside hot springs in Japanese Alps, Japan

Konrad Wothe / Japanese Macaque (Macaca fuscata) group soaking in hot springs, Japanese Alps, Nagano, Japan

Jim Brandenburg / Morning Glory pool in Upper Geyser Basin, Yellowstone National Park, Wyoming

Michael Quinton / Steaming pool in winter, Mammoth Hot Springs, Yellowstone National Park, Wyoming

Mitsuaki Iwago / Japanese Macaque (Macaca fuscata) soaking in hot springs during snow storm, Japan

Tui De Roy / Mato Grosso, limestone springs and waterfalls, Betione, Serra de Bodoquena, Brazil

Shin Yoshino / Japanese Macaque (Macaca fuscata) pair resting in hot spring, Japan

Peter Scoones / Hippopotamus underwater. Mzima Springs, Kenya

Doug Perrine / Juvenile Florida manatee {Trichchus manatus latirostris} Homosassa Springs, Florida, USA. split-level shot , captive (Non-ex).

Peter Scoones / American alligator underwater. Silver Springs, Florida, USA

Peter Scoones / American alligator underwater, Silver Springs, Florida, USA. Captive animal.

John Downer / Minisub used to film hippos underwater for BBC tv series 'Supernatural'. Mzima, Kenya

Steven David Miller / Perentie {Varanus giganteus} Northern Territory, Australia, Alice Springs Reptile Park - largest Australian monitor lizard

George Sanker / Calcite Springs Overlook, view of Grand Canyon of Yellowstone in evening light. Yellowstone National Park, Wyoming, USA. June 2018.

Nick Garbutt / Morning Glory thermal pool surrounded by snow, coniferous forest in background. Near Daisy Geyser Basin, Yellowstone National Park, USA. January 2019.

Nick Garbutt / Travetine terraces, Mammoth hot springs, Yellowstone National Park, USA. January 2019.

Jack Dykinga / View of Heart of Rocks and Sulphur Springs Valley from Massai Point, in morning light with full moon. Chiricahua National Monument, Arizona, USA. 2018.

Robert Valentic / Mengden's brown snake (Pseudonaja mengdeni) male in threat posture, Alice Springs, Northern Territory, Australia.

Robert Valentic / Mengden's brown snake (Pseudonaja mengdeni) male in threat posture, Alice Springs, Northern Territory, Australia.

Heather Angel / Travertine terrace in karst landscape. Huanglong / Yellow Dragon Scenic World Heritage Site, south Minshan range, Sichuan Province, China. 2007.

Heather Angel / Pygmy Rwandan water lily (Nymphaea thermarum) in cultivation at Kew Gardens, London, England, UK. Extinct in the wild. Native to thermal springs, Rwanda.

Milan Radisics / Aerial shot of steam geysers at Gunnhuver Hot Springs, Reykjanes Peninsula, Iceland, August 2018.

Milan Radisics / Aerial shot of steam geysers at Gunnhuver Hot Springs, Reykjanes Peninsula, Iceland, August 2018.

Milan Radisics / Aerial shot of Gunnuhver steam geyser, Gunnhuver Hot Springs, Reykjanes Peninsula, Iceland, August 2018.

Steven David Miller / Central bearded dragon (Pogona vitticeps) warming up on a rock, Alice Springs Reptile Centre, Northern Territory, Australia. Captive.

Steven David Miller / Zebra Finch (Taeniopygia guttata) group bathing on the shallows of a pond, Alice Springs Desert Park, Northern Territory, Australia. Captive.

Steven David Miller / A close up of a Thorny devil (Moloch horridus), Alice Springs Reptile Park, Northern Territory, Australia.

Steven David Miller / Red-capped Robin (Petroica goodenovii), a banded male, Alice Springs Desert Park, Northern Territory, Australia. May. Captive.

Steven David Miller / Red-capped Robin (Petroica goodenovii), a banded male, Alice Springs Desert Park, Northern Territory, Australia. May. Captive.

Steven David Miller / A Red-backed Kingfisher (Todiramphus pyrrhopygius) perching on a tree branch looking for small prey below, Alice Springs Desert Park, Northern Territory, Australia. May. Captive.

Steven David Miller / Red Kangaroo (Macropus rufus) male resting in the shade during the heat of the day, Alice Springs Desert Park, Northern Territory, Australia. May. Captive.

Steven David Miller / Close up of the scutes, or scales of a Perentie (Varanus giganteus), Alice Springs Reptile Centre, Northern Territory, Australia, Captive. May.