The most efficient animal footage of 2023, from hyenas to southern stingrays

This spotted hyena (Crocuta crocuta) pup is a natural in front of the camera, while its mother and sibling keep a watchful eye in the background. This playful shot was taken by Wim van den Heever in Amboseli National Park in southern Kenya.

As the sun rises off the coast of the Cayman Islands, a southern stingray (Dasyatis americana) prowls the sandy seabed in this striking split-level snap by photographer Alex Mustard.

Mustard also captured this vibrantly fluorescent oddity, known as the sap-sucking slug (Costasiella kuroshimae), creeping across green algae just off the coast of northern Indonesia. Two beady eyes sit close together on its face, while spotty green leaf-like appendages called cerata sprout from its body. These sea slugs have the special ability of preserving the chloroplasts in the algae they feed on, which means they can perform photosynthesis.

Deep in the Finnish woods, Andy Rouse snapped this action shot of a Eurasian brown bear (Ursus arctos arctos) shaking itself dry after a quick dip in a pond. These mammals can weigh up to 480 kilograms and are commonly found across eastern Europe and Russia.

In the grasslands of the Rhodope mountains in Bulgaria, Guy Edwardes took this colourful picture of a spotted fritillary (Melitaea didyma) larva. It will eventually transform into a butterfly, whose wings – hints of which can already be seen along its back – will be bright orange with brown spots.

A majestic white-winged snowfinch (Montifringilla nivalis) braves a snowstorm in the Swiss Alps in this photograph by Mateusz Piesiak. They are relatively large, sturdy birds, measuring up to 19 centimetres tall. Their distinctive orange-yellow bills are seasonal, becoming black in the summer.

This bemused fruit bat is having its nose and throat swabbed as part of efforts in the Republic of the Congo to better understand how zoonotic diseases, such as Ebola, could jump to people. Around 100 fruit bats have had their blood and saliva samples taken by researchers from the Wildlife Conservation Society and the Congolese Foundation for Medical Research.