860-291421 - 27-year-old female researcher working on nitrogen exchange between bacteria and the roots of legumes showing an example of a nodule of bacteria attached to the roots in the rainforest of the "La Selva" research station in Puerto Viejo de Sarapiqui, Costa Rica
832-401054 - Yellow-edged moray (Gymnothorax flavimarginatus) at cleaning station with pacific cleaner shrimp (Lysmata amboinensis), Sodwana Bay National Park dive site, Maputaland Marine Reserve, KwaZulu Natal, South Africa, Africa
832-393791 - Close-up, head of a giant moray (Gymnothorax javanicus) opens mouth for two white-banded cleaner shrimps (Lysmata amboinensis), Pacific Ocean, Palau, Oceania
1116-51885 - Close-up of the orange colored plumes of a Christmas tree worm (Spirobranchus giganteus) attached to coral; Maui, Hawaii, United States of America
832-387960 - Pilot Fish (Naucrates ductor) swimming in front of mouth, reef manta ray (Mobula alfredi) with curled up head fins, Great Barrier Reef, Coral Sea, Pacific Ocean, Australia, Oceania
832-387961 - Reef manta ray (Mobula alfredi), silhouette, swimming in blue water, back light, Great Barrier Reef, Coral Sea, Pacific Ocean, Australia, Oceania
832-385368 - Red-billed oxpecker (Buphagus erythrorhynchus), adult, stands on zebra, host animal, symbiosis, Addo Elephant National Park, Eastern Cape, South Africa, Africa
832-387221 - West Indian manatee (Trichechus manatus), overgrown with moss, resting on the bottom, Grass perch, Green sunfish (Lepomis cyanellus) eats moss from manti, cleanerfish, Three Sisters Springs, Manti Sanctuary, Crystal River, Florida, USA, North America
860-287560 - A necessary alliance, a symbiosis even between this moray eel (Gymnothorax javanicus) and this cleaning shrimp (Lysmata amboinensis). Depth: 65m, Mayotte
832-379504 - Masai giraffe (Giraffa camelopardalis), young animal with red-billed oxpeckers (Buphagus erythrorhynchus) on its neck, Masai Mara National Reserve, Narok County, Kenya, Africa
1116-39948 - This soft coral crab or candy crab (Hoplophrys oatesii), is wearing a decoration of soft coral polyps on top of head as camouflage, Dumaguete, Philippines
1116-39939 - An Imperial commensal shrimp (Periclimenes imperator), photographed at night on the Spanish dancer nudibranch (Hexabranchus sanguineus), that it calls home, Philippines
1116-39725 - Mouth detail of a colourful and healthy Mushroom coral, Fungia fungites, that is growing on a tropical coral reef in the Philippines. Mushroom coral is unique in the coral world, in that it does not attach itself to the bottom, Philippines
1116-39729 - Both a Crinoid Commensal Shrimp (Periclimenes cornutus) and a Crinoid Squat Lobster (Allogalathea elegans) on a crinoid. These tiny crustaceans are commensal on crinoids or feather stars and take their color from the host, Philippines
1116-39719 - A Slender Spongegoby (Phyllogobius platycephalops) and two different species of crabs. Attached to the goby are several parasites with egg cases, that will likely prove fatal over time. Many species live on the convuluted surface of this sponge, Philippin
1116-39735 - The strings hanging off the dorsal fin of this Great White Shark (Carcharodon carcharias) are parasitic copepods. Photographed just breaking the surface off Guadalupe Island, Mexico
1116-39953 - This hard coral colony in the Pacific has begun to bleach, expelling its symbiotic zooxanthellae, consequences of global climate change and climate warming, Yap, Micronesia
1116-39938 - Mouth detail of a colorful and healthy mushroom coral (Fungia fungites) that is growing on a tropical coral reef. Mushroom coral is unique in the coral world, in that it does not attach itself to the bottom, Philippines
971-77 - African forest buffalo (Syncerus caffer nanus) with yellow-billed oxpeckers (Buphagus africanus) clinging to its flanks, Parc de la Lekedi, Haut-Ogooue, Gabon, Africa
764-4124 - Masai giraffe (Giraffa camelopardalis tippelskirchi) with a red-billed oxpecker (Buphagus erythrorhynchus), Serengeti National Park, Tanzania, East Africa, Africa
764-3949 - Cape buffalo (African buffalo) (Syncerus caffer) and two yellow-billed oxpeckers (Buphagus africanus), Ngorongoro Crater, Tanzania, East Africa, Africa
869-4163 - striped remora or live sharksucker remora cleaning scraps from inside the mouth of a lemon shark Negaprion brevirostris resting on the bottom is a strong current Thought to be a parasite this is one of the first images showing a benefit for the shark in this relationship West End Grand Bahamas Atlantic Ocean
974-334 - Red sea anemone fish (Amphiprion bicinctus) and magnificent anemone, (Heteractis magnifica), Ras Mohammed National Park, off Sharm el-Sheikh, Sinai, Red Sea, Egypt, North Africa, Africa