Oliver Hellowell / RF - Robin (Erithacus rubecula) juvenile, perched on branch, Bishopswood, Somerset, UK. May. Cropped. (This image may be licensed either as rights managed or royalty free.)

Oliver Hellowell / RF - Great spotted woodpecker (Dendrocopos major) juvenile, perched on mossy log, Bishopswood, Somerset, UK. June. Cropped. (This image may be licensed either as rights managed or royalty free.)

Oliver Hellowell / Red deer (Cervus elaphus) female with fawn standing in upland scrub, Glen Etive, Scotland, UK. October. Cropped.

Joel Sartore / Photo Ark / Variegated squirrel (Sciurus variegatoides rigidus) juvenile, portrait, Rescue Center Costa Rica. Captive.

Tim Laman / Little blue heron (Egretta caerulea) juvenile, perched among a wall of Red mangroves (Rhizophora mangle) in early morning light, at the edge of a lagoon in Caroni Swamp, Trinidad and Tobago.

Joel Sartore / Photo Ark / Eyelash viper (Bothriechis schlegelii) with two juveniles of different color morphs, portrait, from the wild, Tapir Valley, Costa Rica.

Jabruson Motion / Tracking shot of Eastern mountain gorilla (Gorilla beringei beringei) male walking through troop while juveniles and female move out of the way, Virunga National Park, Democratic Republic of Congo. 19...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile swinging on overhanging vine, Virunga National Park, Democratic Republic of Congo. 1996.

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile clambering over head and shoulders of young male. The camera moves closer and focuses on young male. Virunga National Park, Democratic Rep...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile climbing down a vine and sitting on young male. Virunga National Park, Democratic Republic of Congo. 1996.

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) young male eating. The gorilla becomes aware of the camera and stops eating, then the animal stares in fascination at the camera. Virunga National...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) young male eating. The gorilla becomes aware of the camera and stops eating, then the animal stares at the camera. Virunga National Park, Democrati...

Jabruson Motion / Tracking shot of Eastern mountain gorilla (Gorilla beringei beringei) young male moving past the camera with a twig in its mouth. The goriilla sits down in the undergrowth. Virunga National Park, Demo...

Jabruson Motion / Close up of Eastern mountain gorilla (Gorilla beringei beringei) young male head looking inquisitively at the camera. The gorilla has a twig in its mouth. Virunga National Park, Democratic Republic of...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) young male walking toward camera. Then the animal stops and looks down at the camera in fascination. The gorilla has a twig in its mouth. Virunga N...

Jabruson Motion / Close up of Eastern mountain gorilla (Gorilla beringei beringei) juvenile head looking at camera. The camera zooms out and the juvenile gorilla moves to another gorilla, sitting in undergrowth, for co...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile looking inquisitively at the camera. In the background, a female is sitting in the undergrowth and eating. Virunga National Park, Democra...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) climbing up small branch. The animal stops climbing the branch, when it realises it is too heavy for it and the branch bends over. Virunga Nationa...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile peering over small branch and then looking inquisitively at the camera. The animal moves away and sits down with male gorilla, in the back...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) female and juvenile sitting on bed of vegetation. The juvenile peers over shoulder of female and then looks inquisitively at the camera. Virunga Na...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) female sitting on bed of vegetation, looking at juvenile which enters frame and walks past. Virunga National Park, Democratic Republic of Congo. 19...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juveniles playing. One juvenile is swinging on a vine and then the other animal pulls them off it and onto the ground. Virunga National Park, Democ...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile and adult sitting side by side. The young gorilla is grooming whilst the adult watches. Virunga National Park, Democratic Republic of Cong...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile swinging on a overhanging vine. Another juvenile emerges from vegetation and pulls the other gorilla off the vine. Virunga National Park,...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile looking at the camera and swinging on a overhanging vine. The young gorilla stops playing and sits down in the vegetation. Virunga Nationa...

Jabruson Motion / Eastern mountain gorilla (Gorilla beringei beringei) juvenile swinging on a overhanging vine. Another juvenile steals the vine and then an adult comes over to intervene, stopping a forthcoming fight....

Neil Aldridge / African lion (Panthera leo) cubs play-fighting. One cub stands up and starts walking away while the other cub chases. Okavango Delta, Botswana.

Neil Aldridge / African lion (Panthera leo) cubs play-fighting, Okavango Delta, Botswana.

Neil Aldridge / Tracking shot of African lion (Panthera leo) cub walking through Kalahari scrub and leaving the frame, Okavango Delta, Botswana.

Neil Aldridge / Tracking shot of African lion (Panthera leo) mother walking through Kalahari scrub with two cubs. Then the mother lies down. Okavango Delta, Botswana.

Neil Aldridge / African lion (Panthera leo) mother with cubs. The cubs walk around while the mother yawns and defecates. Okavango Delta, Botswana.

Neil Aldridge / African lion (Panthera leo) cub walks over to its mother, who is lying down, and rubs its head against hers. The cub sits down next to its mother and then walks out of the frame. Okavango Delta, Botsw...

Neil Aldridge / African lion (Panthera leo) cub standing and looking around, before lying down, Okavango Delta, Botswana.

Neil Aldridge / African lion (Panthera leo) cub lying down near its mother and grooming itself, in evening light. The cub is licking its paws. Okavango Delta, Botswana.

Neil Aldridge / Tracking shot of African lion (Panthera leo) juvenile male walking near the water's edge, Okavango Delta, Botswana.

Neil Aldridge / African lion (Panthera leo) juvenile male yawning, Khwai, Okavango Delta, Botswana.

Nick Upton / Common crane (Grus grus) juvenile walking through marshland plants, Slimbridge, Gloucestershire, UK, August.

Nick Upton / Common crane (Grus grus) parent flying and calling with fledgling, Slimbridge, Gloucestershire, UK, August.

Nick Upton / Common crane (Grus grus) juvenile taking flight for the first time from marshland, Slimbridge, Gloucestershire, UK, August.

Nick Upton / Common crane (Grus grus) adult and juvenile walking through marshland, Slimbridge, Gloucestershire, UK, August.

Nick Upton / Great cormorant (Phalacrocorax carbo) juvenile taking off from water, Cannop Ponds, Forest of Dean, Gloucestershire, UK, October.

Nick Upton / Great cormorant (Phalacrocorax carbo) juvenile in flight, Cannop Ponds, Forest of Dean, Gloucestershire, UK, October.

Roman Willi / African buffalo (Syncerus caffer) calf and adult standing in grassland, Mikumi National Park, Tanzania.

Roman Willi / Black redstart (Phoenicurus ochruros) male, perched in hole in wooden shed bringing food to its chicks, Lucerne, Switzerland. July.

Roman Willi / Hourglass treefrog (Dendropsophus ebraccatus) juvenile, portrait, Limon, Costa Rica.

Juergen Freund / Volunteer at the Tolga Bat Hospital cradling three juvenile Spectacled flying foxes (Pteropus conspicillatus) rescued by volunteers from a nearby forest, after their mothers died from the effects of p...

Tui De Roy / Community member releasing Green turtle (Chelonia mydas) hatchlings from incubation pen as part of 30 year community-based beach patrolling, protection of nests and females and natural hatchery scheme...

Andy Rouse / African elephant (Loxodonta africana), mother and calf, at sunset. Lumo Wildlife Sanctuary, Tsavo National Park, Kenya.

Tim Laman / Full skin of Wreathed hornbill (Rhyticeros undulatus), skull and casque of Rhinoceros hornbill (Buceros rhinoceros) and casque of young Helmeted hornbill (Rhinoplax vigil), displayed on floor as troph...

Tim Laman / Iban hunter displaying skin of Wreathed hornbill (Rhyticeros undulatus), skull and casque of Rhinoceros hornbill (Buceros rhinoceros) and casque of a young Helmeted hornbill (Rhinoplax vigil) on floor...

Tim Laman / Iban hunter displaying skin of Wreathed hornbill (Rhyticeros undulatus), skull and casque of Rhinoceros hornbill (Buceros rhinoceros) and casque of a young Helmeted hornbill (Rhinoplax vigil) on floor...

Eric Baccega / Two Olive baboons (Papio anubis) sitting in grassland with female grooming her infant, Kibale National Park, Uganda.

Eric Baccega / Two Olive baboons (Papio anubis) sitting in grassland with female grooming her infant, Kibale National Park, Uganda.

Eric Baccega / Olive baboon (Papio anubis) female feeding on vegetation with infant on her back, Kibale National Park, Uganda.

Eric Baccega / Chimpanzee (Pan troglodytes schweinfurthii) female feeding on fruit in tree and carrying infant, aged 6 months, Kibale National Park, Uganda.

Eric Baccega / Chimpanzee (Pan troglodytes schweinfurthii) female feeding on fruit in tree and carrying infant, aged 6 months, Kibale National Park, Uganda.

Eric Baccega / Chimpanzee (Pan troglodytes schweinfurthii) female feeding on fruit in tree and carrying infant, aged 6 months, Kibale National Park, Uganda.

Eric Baccega / Chimpanzee (Pan troglodytes schweinfurthii) female feeding on fruit in tree and carrying infant, aged 6 months, Kibale National Park, Uganda.

Eric Baccega / Mountain gorilla (Gorilla beringei) silverback male, infant aged 2 years, playing with his brother, aged 6 years, among trees. Part of the Nyakagezi group, Mgahinga National Park, Uganda. Critically e...

Eric Baccega / Mountain gorilla (Gorilla beringei) silverback male, infant aged 2 years, playing with his brother, aged 6 years, among trees. Part of the Nyakagezi group, Mgahinga National Park, Uganda. Critically e...

Eric Baccega / Mountain gorilla (Gorilla beringei) silverback male, infant aged 2 years, playing with his brother, aged 6 years, among trees. Part of the Nyakagezi group, Mgahinga National Park, Uganda. Critically e...

Eric Baccega / Mountain gorilla (Gorilla beringei) silverback male, infant aged 2 and half years, portrait. Member of the Nyakagezi group. Mgahinga National Park, Uganda. Critically endangered.

Eric Baccega / Mountain gorilla (Gorilla beringei) silverback male, infant aged 2 and half years, sitting in tree feeding on leaves. Member of the Nyakagezi group. Mgahinga National Park, Uganda. Critically endanger...

Eric Baccega / RF - Topi (Damaliscus lunatus jimela) female with calf, standing in savanna, Akagera National Park, Rwanda. (This image may be licensed either as rights managed or royalty free.)

Eric Baccega / RF - Chimpanzee (Pan troglodytes schweinfurthii) infant aged 6 months, sitting on its mother whilst feeding on a leaf, Kibale National Park, Uganda. (This image may be licensed either as rights manage...

Eric Baccega / RF - Olive baboon (Papio anubis) female, foraging among vegetation carrying infant on her back, Kibale National Park, Uganda. (This image may be licensed either as rights managed or royalty free.)

Eric Baccega / RF - Chimpanzee (Pan troglodytes schweinfurthii) female feeding on fruit in tree and carrying infant, aged 6 months, her back. Kibale National Park, Uganda. (This image may be licensed either as right...

Eric Baccega / RF - Mountain gorilla (Gorilla beringei) silverback male infant, aged 2 and half, resting in tree. Member of the Nyakagezi group. Mgahinga National Park, Uganda. Critically endangered. (This image may...

Eric Baccega / Topi (Damaliscus lunatus jimela) female with calf walking through savanna, Akagera National Park, Rwanda.

Joel Sartore / Photo Ark / Smoky jungle frog (Leptodactylus pentadactylus) juvenile, portrait, Urku Center, Tarapoto, Peru. Captive.

Joel Sartore / Photo Ark / Ringed salamander (Ambystoma annulatum) juvenile, portrait, Amphibian Foundation Atlanta, Georgia, USA. Captive.

Joel Sartore / Photo Ark / Three Ringed salamander (Ambystoma annulatum) juveniles, portrait, Amphibian Foundation Atlanta, Georgia, USA. Captive.

Joel Sartore / Photo Ark / Two Yosemite toad (Anaxyrus canorus) juveniles, side by side, one with mouth open, portrait, Museum of Vertebrate Zoology at U.C. Berkeley, California, USA. Captive. Endangered.

David Pattyn / White stork (Ciconia ciconia) pair with chicks standing on nest built on church wall, Trujillo, Extremadura, Spain. May.

David Pattyn / White stork (Ciconia ciconia) with chicks, standing on nest on giant boulders at sunset, Los Barruecos, Malpartida de Caceres, Extremadura, Spain. May.

David Pattyn / RF - Two White storks (Ciconia ciconia) standing on their nests on top of giant boulders at sunset, Los Barruecos, Malpartida de Caceres, Extremadura, Spain. May. (This image may be licensed either as...

David Pattyn / White stork (Ciconia ciconia) with chicks on nest built at end of an abandoned crane, Extremadura, Spain. May.

David Pattyn / Whiskered tern (Chlidonias hybrida) chick on nest among aquatic vegetation, mainly Water soldier (Stratiotes aloides) plants, on river, Danube delta, Romania. July.

Joel Sartore / Photo Ark / Rosenberg gladiator frog (Boana rosenbergi) juvenile, portrait, Centro Jambatu, Quito, Ecuador. Captive.

Joel Sartore / Photo Ark / Night frog (Astylosternus sp.) tadpole, portrait, from the wild, Cameroon. Captive.

David Pattyn / Cotton-top tamarin (Saguinus oedipus) female carrying infant on back, resting in tree, Colombia. Critically endangered.

David Pattyn / Cotton-top tamarin (Saguinus oedipus) female carrying infant on back, resting in tree, Colombia. Critically endangered.

Daniel Nunez / Spider monkey (Ateles geoffroyi) rescued infant, being bottle fed at ARCAS Rescue Center, Peten, Guatemala. January, 2023. Endangered. Cropped.

Will Watson / Flat-headed mayfly (Ecdyonurus sp.) nymph, resting underwater, Humber Brook, Herefordshire Plateau, England, UK. October. Controlled conditions using microscopy.

Will Watson / Flat-headed mayfly (Ecdyonurus sp.) nymph, resting underwater, Humber Brook, Herefordshire Plateau, England, UK. October. Controlled conditions using microscopy.

Will Watson / Cranefly (Tipula sp.) larva, portrait showing breathing holes and appendages, River Frome, Bromyard, Herefordshire, England, UK. November. Controlled conditions using microscopy.

Will Watson / Beautiful demoiselle (Calopteryx virgo) nymph, resting on Water moss (Fontinalis sp.), River Lugg SSSI, Herefordshire, England, UK. October. Controlled conditions, focus stacked and retouched.

Edwin Giesbers / Great raft spider (Dolomedes plantarius) spiderlings on their nursery web, The Netherlands.

Edwin Giesbers / Wild cat (Felis silvestris) kitten sitting in grass, Germany. June. Captive.

Edwin Giesbers / Great raft spider (Dolomedes plantarius) female guarding spiderlings in the nursery web, The Netherlands.

Edwin Giesbers / Great raft spider (Dolomedes plantarius) spiderlings on their nursery web, The Netherlands.

Edwin Giesbers / Great raft spider (Dolomedes plantarius) female guarding spiderlings in nursery web among grass along riverbank, The Netherlands.

Edwin Giesbers / Wild cat (Felis silvestris) female and kitten resting in undergrowth, Germany. Captive.

Edwin Giesbers / Wild cat (Felis silvestris) kitten resting, portrait, Germany. Captive.

Franco Banfi / European bison (Bison bonasus) herd with calves stand in field beside forest, Bialowieza Forest UNESCO World Heritage Site, Poland.

Neil Aldridge / Bornean orangutan (Pongo pygmaeus) juvenile sits in tree and looks around before beginning to climb, Sepilok Orangutan Sanctuary, Sabah, Borneo, Malaysia. Endangered.