Colin Varndell / Blue tit brings caterpillar to young in nestbox {Parus caeruleus} UK

Alex Mustard / Grey seal (Halichoerus grypus) young seal gapes mouth showing teeth in playful mood, Lundy Island, Devon, UK, Bristol Channel, August

Alex Mustard / Grey seal (Halichoerus grypus) young male plays and gapes, showing his teeth.Lundy Island, Devon, UK, Bristol Channel, August

Robert Valentic / Speckled brown snake {Pseudonaja guttatus} male banded phase gapes and flattens its hood in threat display, Barkly Tableland, Northern Territory, Australia