Franco Banfi / Spectacled caiman (Caiman crocodilus) Rio Bai­a Bonita, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Green anaconda (Eunectes murinus) close up underwater in Formoso River, Bonito, Mato Grosso do Sul, Brazil

Michael Durham / Pacific Lamprey (Petromyzon tridentatus) juvenile using sucker-like mouth parts to attach itself to rock, Columbia River Research Laboratory, Willard, Washington

Michael Durham / Pacific Lamprey (Petromyzon tridentatus) juvenile using sucker-like mouth parts to attach itself to glass of aquarium, Columbia River Research Laboratory, Willard, Washington

Martin Dohrn / Bullet ant (Paraponera clavata) portrait showing mandibles, from South America

Jan Hamrsky / Spike-tail Dragonfly (Cordulegaster) nymph portrait showing fearsome mouth parts. Europe, August.

Jan Hamrsky / Great Diving Beetle (Dytiscus marginalis) larva with open mouth parts. Europe, June.

Jan Hamrsky / Northern Emerald Dragonfly (Somatochlora arctica) nymph close-up showing mouth parts. Europe, May.

Jan Hamrsky / Northern Emerald Dragonfly (Somatochlora arctica) nymph, ventral view showing mouth parts. Europe, May.

Alex Hyde / Wartlet / Gem Anemone (Bunodactis verrucosa) in rockpool, with mouth parts visible, Pembrokeshire, Wales, UK. July.

Steven David Miller / Badge Huntsman spider (Neosparassus) sitting on tree trunk, detail of eyes, palps, mouth parts, Undara Volcanic National Park, North Queensland, Australia

Jeff Rotman / Nostrils and mouth parts of Port Jackson shark (Heterodontus philippi) at night, South Australia, Great Australian Bight