Tony Heald / RF- African elephant (Loxodonta africana) young males play fighting, Etosha National Park, Namibia, June. Endangered species. (This image may be licensed either as rights managed or royalty free.)

Doug Perrine / RF- Green sea turtle (Chelonia mydas) being cleaned by herbivorous cleaner fish species Yellow tangs (Zebrasoma flavescens) and Gold-ring surgeonfish (Ctenochaetus strigosus) that graze algae on turtl...

Doug Perrine / RF- Male Hawaiian monk seal (Monachus schauinslandi) spyhopping off East Island, looking for females, French Frigate Shoals, Papahanaumokuakea Marine National Monument, Northwest Hawaiian Islands, US...

Andy Rouse / RF- Black rhinoceros (Diceros bicornis) waiting to charge, South Africa. Critically endangered species. (This image may be licensed either as rights managed or royalty free.)

Tony Heald / RF- African elephant (Loxodonta africana) young males play fighting, Etosha National Park, Namibia, June. Endangered species. (This image may be licensed either as rights managed or royalty free.)

Tony Heald / RF- African elephants (Loxodonta africana) trunks raised to scent for danger. Etosha national park, Namibia. Endangered species. (This image may be licensed either as rights managed or royalty free.)