David Perpinan / Necrosis / tissue dying in hemipenis of captive garter snake (Thamnophis sirtalis) small repro only

David Perpinan / Phallus/penile prolapse in a captive Yellow bellied slider (Trachemys scripta). Small repro only

Shane Gross / Nurse sharks (Ginglymostoma cirratum) ready to mate. Showing male claspers, which are used to channel semen into the female during mating, Eleuthera, Bahamas.

Shane Gross / Nurse sharks (Ginglymostoma cirratum) ready to mate. Showing male claspers, which are used to channel semen into the female during mating, Eleuthera, Bahamas.

Franco Banfi / Zebu bull, Bonito, Mato Grosso do Sul, Brazil

Staffan Widstrand / Wild Wonders of China / Portrait of a male Golden snub-nosed monkey (Rhinopithecus roxellana) Foping Nature Reserve, Shaanxi, China. Endangered species

MYN / Lily Kumpe / Balloon-winged katydid (Tympanophora diminuta) female, William Bay National Park, Western Australia. Meetyourneighbours.net project.

MYN / Lily Kumpe / Giant ichneumon wasp (Megarhyssa) female with very long ovipositor, Dugana Khad, Tuv Province, Mongolia. Meetyourneighbours.net project.

Daniel Heuclin / Potto (Perodicticus potto) male in tree, Togo. Captive.

Tony Wu / Humpback whale (Megaptera novaeangliae) male blowing bubbles, likely a display of dominance during heat run. The male had a small portion of his penis protruding. Vava'u, Tonga. Pacific Ocean.

Claudio Contreras / Olive Ridley Sea Turtle (Lepidochelys olivacea) nesting, egg in nest, Arribada (mass nesting event), Playa Morro Ayuta, Oaxaca state, southern Mexico, IUCN Vulnerable, August

Kim Taylor / Rose sawfly (Arge ochropus) female cutting a groove in a rose stem in which to lay her eggs. Surrey, England, UK, June.