Chien Lee / Pygmy Anteater (Cyclopes didactylus) mother and young, Esmeraldas, Ecuador

Richard Robinson / Maui's dolphin (Cephalorhynchus hectori maui) Critically Endangered, the world's smallest and rarest marine dolphin. Endemic to North Island, New Zealand. October. Editorial use only.

Richard Robinson / Maui's dolphins (Cephalorhynchus hectori maui) Critically Endangered, the world's smallest and rarest marine dolphin. Endemic to North Island, New Zealand, March. Editorial use only.

Barrie Britton / Nosy Be Pygmy Leaf Chameleon (Brookesia minima) female, the world's second smallest reptile species, Nosy Be, Madagascar. Photograph taken on location for BBC 'Wild Madagascar' Series, January 2010

Konrad Wothe / Blue-tailed Hummingbird (Amazilia cyanura) feeding at flowers, Honduras

Michael Durham / Western Pipistrelle (Pipistrellus hesperus) bat flying over desert scrub, near Pine Creek in the John Day Fossil Beds National Monument, Clarno Unit, Oregon, this is the smallest bat found north of Me...

Claus Meyer / Pygmy Marmoset (Cebuella pygmaea) endangered, pair, world's smallest primate, Amazon, Brazil

Fred Bavendam / Pygmy Seahorse (Hippocampus bargibanti) clinging to a Gorgonian Coral Fan, Lembeh Straits, Sulawesi, Indonesia

Fred Bavendam / Pygmy Seahorse (Hippocampus bargibanti) clinging to a Gorgonian Coral Fan, Lembeh Straits, Sulawesi, Indonesia

Phil Savoie / Smeathman's Furrow Bee (Lasioglossum smeathmanellum) visiting Oxeye Daisy (Leucanthemum vulgare) feeding and pollinating florettes. At 4.5 mm average size, this is one of the smallest bees in the UK,...

Phil Savoie / Smeathman's furrow bee (Lasioglossum smeathmanellum) visiting Biting stonecrop (Sedum acre) At 4.5 mm average size, this is one of the smallest bees in the UK, Monmouthshire Wales, June.

Phil Savoie / Smeathman's furrow bee (Lasioglossum smeathmanellum) visiting Purple Toadflax (Linaria purpurea). At 4.5 mm average size, this is one of the smallest bees in the UK, Monmouthshire Wales, July.