Anup Shah / Bonobo (Pan paniscus) baby aged 3 months sucking it's mother's finger, Lola Ya Bonobo Sanctuary, Democratic Republic of Congo. October.

Alex Hyde / Cleg fly / Horsefly (Haematopota pluvialis) sucking blood from human.

Nick Upton / Cleg fly / Horsefly (Haematopa pluvialis) sucking blood from photographer's arm, Wiltshire pastureland, UK, June.

Stephen Dalton / Horsefly (Tabanus sudeticus) feeding on human skin, UK

Kim Taylor / Mosquito (Aedes punctor) female resting after sucking blood from human arm. Sequence 4/4

Kim Taylor / Mosquito (Aedes punctor) female sucking blood from human arm. Sequence 3/4

Kim Taylor / Mosquito (Aedes punctor) female sucking blood from human arm. Sequence 1/4

Luiz Claudio Marigo / Blue grecian butterfly sucking water from soil {Heliconius wallacei} Brazil

Kim Taylor / Long-winged Conehead (Conocephalus discolor) female sucking its hind foot, UK.

Martin Dohrn / Mosquito gorged with human blood {Culex pipiens} UK

Rolf Nussbaumer / Leaf hopper adult bugs sucking sap {Cicadellidae} Texas, USA.

Warwick Sloss / Mosquito {Anopheles gambiae} female sucking blood from human

Piotr Naskrecki / Biting Midge (Forcipomyia tettigonaris) parasite feeding on Katydid (Cycloptera speculata) hemolymph, Suriname

Alex Mustard / A Whale shark (Rhincodon typus) mouth open feeding on fish eggs by sucking in water, a behaviour known as botella because the shark hangs vertical in the water like a bottle gulping in food, Isla Muje...

Christophe Courteau / Red lechwe mother suckling calf {Kobus leche}. Khwai river, Moremi GR, Botswana.

Fiona Rogers / Western lowland gorilla (Gorilla gorilla gorilla) infant 'Sopo' aged 18 months sucking on a piece of rotten wood, Bai Hokou, Dzanga Sangha Special Dense Forest Reserve, Central African Republic. Decem...

Steven Kazlowski / Moose (Alces alces) newborn calves sucking from their mother as she forages on spring willow leaves. Tony Knowles Coastal Trail, Anchorage, south-central Alaska, May.

Juergen Freund / Spectacled flying fox (Pteropus conspicillatus) babies swaddled up in cloth ready to sleep, teats in mouths ready to be fed, Tolga Bat Hospital, Atherton, North Queensland, Australia. January 2008.

Konrad Wothe / Leech on skin in rainforest, West Papua, Indonesia

Roland Seitre / Baby Hoffman's Two Toed Sloth (Choloepus hoffmanni) sucking its claw. Aviarios del Caribe Sloth Sanctuary, Costa Rica, 2008.

Loic Poidevin / Grey / Lesser mouse lemur (Microcebus murinus) sucking sap from tree, Madagascar.

Nick Upton / Stable fly (Stomoxys calcitrans) piercing skin to suck blood from photographer's ankle, Samos, Greece, August.

Piotr Naskrecki / Vampire Bat (Desmodus rotundus) with parasitic Louse Flies (Trichobius parasiticus) behind its ear, Sipaliwini, Surinam

Piotr Naskrecki / Biologist Ingi Agnarsson collecting kleptoparasitic spiders that live as squatters in the web of the giant orb weaver, Papua New Guinea

David Maitland / Pigeon louse fly (Ornithomya avicularia) amongst the feathers of a Tawny Owl (Strix aluco). Feltwell, Norfolk, UK.

David Maitland / Pigeon louse fly (Pseudolynchia canariensis) amongst the feathers of a Tawny Owl (Strix aluco). Feltwell, Norfolk, UK.

Fiona Rogers / Bonobo (Pan paniscus) male baby aged 10 months with his mother 'Nioki', lying on his mother's foot 'sucking his thumb', Lola Ya Bonobo Sanctuary, Democratic Republic of Congo. October.

Juergen Freund / Sap sucking sea slug (Elysia ornata) New Ireland, Papua New Guinea

Juergen Freund / Dugong (Dugong dugon) feeding in the seagrass bed shadowed by a trevally. Dimakya Island, Palawan, Philippines.

Juergen Freund / Dugong (Dugong dugon) feeding in the seagrass bed shadowed by a trevally. Dimakya Island, Palawan, Philippines.

Juergen Freund / Dugong (Dugong dugon) feeding in the seagrass bed shadowed by a trevally. Dimakya Island, Palawan, Philippines.

Juergen Freund / Dugong (Dugong dugon) feeding in the seagrass bed shadowed by a trevally. Dimakya Island, Palawan, Philippines.

Juergen Freund / Dugong (Dugong dugon) feeding in the seagrass bed shadowed by a trevally. Dimakya Island, Palawan, Philippines.

Juergen Freund / Dugong (Dugong dugon) feeding in the seagrass bed shadowed by a trevally. Dimakya Island, Palawan, Philippines.

Juergen Freund / Horned helmet conch snail (Cassis cornuta) feeding on by sucking out a Sand dollar, Palawan, Philippines, Indo-pacific.

Anup Shah / Bornean Orangutan (Pongo pygmaeus wurmbii) male baby 'Thor' aged 8-9 months sucking his hands and feet - portrait. Camp Leakey, Tanjung Puting National Park, Central Kalimantan, Borneo, Indonesia. Jul...

Nick Upton / Shield-backed / Jewel bug (Odontotarsus purpureolineatus), sucking plant juices from Crown daisy (Chrysanthemum coronarium), Corsica, France, May.

Nick Upton / Common / Long Water Measurer (Hydrometra stagnorum) on water surface, with Springtail prey impaled on its sucking rostrum. Wiltshire, UK, April.

Tim Laman / Borneo tiger leech (Haemadipsa picta) feeding on human skin, Gunung Palung National Park, Borneo, West Kalimantan, Indonesia

Tim Laman / Pulling off Tiger land leeches (Haemadipsa picta) during a hike in the rainforest, Gunung Palung National Park, Borneo, West Kalimantan, Indonesia

Tim Laman / Pulling off Tiger land leeches (Haemadipsa picta) during a hike in the rainforest, Gunung Palung National Park, Borneo, West Kalimantan, Indonesia

Tim Laman / Borneo Tiger leech (Haemadipsa picta) engorged with blood opn human hand, Gunung Palung National Park, Borneo, West Kalimantan, Indonesia

Nick Upton / Sequence 2 / 4. Cleg fly / Horsefly (Haematopa pluvialis) sucking blood from photographer's hand Wiltshire pastureland, UK, June.

Nick Upton / Sequence 1 / 4. Cleg fly / Horsefly (Haematopa pluvialis) about to pierce human skin a second time with blade like mouthparts. Wiltshire pastureland, UK, June.

Nick Upton / Sequence 3 / 4. Cleg fly / Horsefly (Haematopa pluvialis) excreting excess water as it swells up with blood sucked from photographer's arm, Wiltshire pastureland, UK, June.

Nick Upton / Sequence 4 / 4. Cleg fly / Horsefly (Haematopa pluvialis) swollen with blood sucked from photographer's hand, Wiltshire pastureland, UK, June.

Luiz Claudio Marigo / Black-patched Metalmark butterfly (Lasaia agesilas) sucking liquid from the ground in the Amazon Upland Rainforest of Manu National Park, Cusco Department, Peru.

Luiz Claudio Marigo / Zebra mosaic butterfly (Colobura dirce) and grasshoppers sucking mineral salts from faeces of carnivore in Amazon Upland Rainforest of Manu National Park, Cusco Department, Peru.

Luiz Claudio Marigo / Starry night metalmark butterfly (Echydna punctata) sucking liquid from the ground in the Amazon Upland Rainforest of Manu National Park, Cusco Department, Peru.

Luiz Claudio Marigo / Mesentina Sister butterfly (Adelpha mesentina) sucking liquid from the ground in the Amazon Upland Rainforest of Manu National Park, Cusco Department, Peru.

Luiz Claudio Marigo / Fugela Sister butterfly (Adelpha fugela) right and Mesentina Sister butterfly (Adelpha mesentina) sucking liquid from the ground in the Amazon Upland Rainforest of Manu National Park, Cusco Department...

Luiz Claudio Marigo / (Tegosa sp) butterfly sucking water with mineral salts from the ground on the margin of Cristalino River, Alta Floresta, Mato Grosso State, Brazil.

Luiz Claudio Marigo / Periander metalmark / Periander swordtail butterfly (Rhetus periander) sucking water with mineral salts from the ground on the margin of Cristalino River, Alta Floresta, Mato Grosso State, Brazil.

Luiz Claudio Marigo / Amazon beauty butterfly (Baeotus aeilus) sucking liquid on rock beside Cristalino River, Cristalino Jungle Lodge, Alta Floresta, Mato Grosso State, Brazil

Kim Taylor / Pioneer white butterflies (Anaphaeis / Belenois aurota) sucking mineral-rich moisture from damp earth, Namibia

Piotr Naskrecki / Cup Moth (Limacodidae) caterpillar being predated on by Stink Bug (Pentatomidae), Ghana

Doug Perrine / Marlin sucker / remora (Remora osteochir) showing sucking / attachment disc, Kona, Hawaii. Captive.

Yukihiro Fukuda / Japanese macaque / Snow monkey {Macaca fuscata} 8-month-old monkey bathing in hot springs, sucking finger, water at 40 degrees, Jigokudani, Nagano, Japan

Doug Perrine / Marlin suckerfish / remora (Remora osteochir) showing sucking attachment disc, Kona, Hawaii. Captive.

Doug Perrine / Marlin sucker / remora (Remora osteochir) close-up showing tiny teeth on edges of sucking / attachment disc, Kona, Hawaii. Captive.

Doug Perrine / Marlin sucker / remora (Remora osteochir) showing sucking / attachment disc, Kona, Hawaii. Captive.

Jane Burton / Sucking catfish {Hypostomus / Plecostomus plecostomus} attached by its sucking mouth to the glass of a fish tank, captive

Jane Burton / Sucking catfish {Hypostomus / Plecostomus plecostomus} captive

Jane Burton / Sucking catfish {Hypostomus / Plecostomus plecostomus} attached to submerged branch by sucker on mouth, captive

Norbert Wu / Leech (Notostomobdella cyclostoma) on the eye of a Lingcod (Ophiodon elongatus), Vancouver Island, British Columbia, Canada

Nick Upton / Hood island mocking birds (Nesomimus trifasciatus macdonaldi) sucking blood from Nazca booby (Sula granti) chick, Galapagos

Miles Barton / Madagascan day gecko (Phelsuma madagascariensis) on tree trunk lapping honey dew from a sap sucking planthopper insect (invisible). Kirindy Dry Forest, Madagascar.

Albert Lleal / Asian Tiger Mosquito (Aedes albopictus) SEM close-up view of tip of buccal sucking apparatus

SINCLAIR STAMMERS / Mosquito {Anopheles stephensi} sucking human blood

SINCLAIR STAMMERS / Mosquito {Anopheles stephensi} sucking human blood

SINCLAIR STAMMERS / Mosquito {Anopheles stephensi} sucking human blood

PREMAPHOTOS / Leafhoppers (Rhaphirrhinus phosphoreus) sucking sap from a rainforest tree and exuding honeydew on to the leaf from their rear ends, Peru

Warwick Sloss / Mosquito {Anopheles gambiae} female sucking blood from human

Nature Production / Mosquito {Culex pipiens molestus} sucking blood from human, Asia

Nature Production / Saw Stag Beetle {Prosopocoilus inclinatus inclinatus} sucking sap, close-up, Japan

Nature Production / Clown Stink Bug {Poecilocoris lewisi} sucking from Kobus Magnolia fruit, Japan

Nature Production / Shield bug {Picromerus fuscoannulatus} sucking body fluid from caterpillar larva of Oriental moth{Monema flavescens} Japan

Flip Nicklin / Bearded Seal (Erignathus barbatus) captured seal sucks on researcher's finger for comfort, Svalbard, Norway

Suzi Eszterhas / Spotted Hyena (Crocuta crocuta) ten week old cub playing with penis/phallus, Masai Mara Conservancy, Kenya

PREMAPHOTOS / Leaf-footed bug (Machtima crucigera) warningly coloured, sucking sap from a vine stem in the campo cerrado, Brazil

Nature Production / Common Mormon butterfly {Papilio polytes polytes} sucking nectar from Common Lantana flowers, Okinawa, Japan

Nature Production / Asian Tiger Mosquito {Aedes albopictus} after sucking blood, Japan

Nick Gordon / Jaguar female sucking tiny cub in den (Panthera onca) Amazonia, Brazil. Captive.

Nature Production / Giant resin bee {Megachile sculpturalis} sucking nectar from Bush / Japanese Clover {Lespedeza sp}, Japan

Nature Production / Brown-eared Bulbul {Microscelis amaurotis} with mouth dyed yellow with pollen from sucking nectar from Camellia flowers, Tokyo, Japan

Nature Production / Old World Yellow Swallowtail butterfly {Papilio machaon hippocrates} male sucking nectar from Thistle {Cirsium oligophyllum} Saitama, Japan

Ingo Arndt / Equatorial Saki (Pithecia aequatorialis) sucking its thumb, Amazon ecosystem, Peru

Suzi Eszterhas / Mountain Gorilla (Gorilla gorilla beringei) three month old infant sucking on thumb, endangered, Parc National Des Volcans, Rwanda

Piotr Naskrecki / Lantern Bug (Enchophora rosacea) with a Moth sucking the honeydew it produces, Costa Rica

Piotr Naskrecki / Lantern Bug (Enchophora rosacea) with a Moth sucking the honeydew it produces, Costa Rica

Kim Taylor / Mosquito (Aedes punctor) female sucking blood from human arm. Sequence 2/4

Anup Shah / Chimpanzee {Pan troglodytes} portrait of orphaned juvenile 'Sophie', sucking piece of grass, Sweetwater Sanctuary, Kenya

Pete Oxford / Greater dwarf lemur {Cheirogaleus major} sucking gum from tree at night, Masoala Peninsula, Madagascar

Pete Oxford / Pale fork-marked lemur {Phaner furcifer pallescens}sucking gum from tree, Western Dry Forest, Madagascar

Mary McDonald / Young Olive baboon sucking thumb (Papio anubis) Nakuru NP, Kenya

Mary McDonald / Baby Olive baboon sucking thumb. (Papio anubis) Nakuru NP, Kenya