Jami Tarris / Caribou (Rangifer tarandus) entering teepee for food, Khovsgol, Mongolia

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) swimming close to surface. Brothers Islands, Egypt.

Shane Gross / Caribbean reef shark (Carcharhinus perezi), two from below, one close up. Caribbean Sea off Gardens of the Queen National Park, Cuba.

Mark Raycroft / Woodland Caribou (Rangifer tarandus caribou) mother nursing calf, Newfoundland, Canada

Mark Raycroft / Woodland Caribou (Rangifer tarandus caribou) male, Newfoundland, Canada

Tony Wu / Blacktip reef shark (Carcharhinus melanopterus) beaching itself to catch sardines. Tonga South Pacific.

Alex Mustard / Blacktip reef shark (Carcharhinus melanopterus) swims through schools of fish. Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean.

Ann & Steve Toon / Photographer Ann Toon photographing Cape ground squirrels (Xerus inauris) Kgalagadi Transfrontier Park, South Africa, January 2016. Model released.

Nick Upton / Forest caterpillar hunter (Calosoma sycophanta) feeding on a Gypsy moth caterpillar (Lymantria dispar) it has killed in a Holm oak tree, Bacu Goloritze ravine, Baunei, Sardinia, Italy, May.

Nick Hawkins / Blue shark (Prionace glauca) with a pair of pilot fish (Naucrates ductor) off Halifax, Nova Scotia, Canada. July.

Nick Hawkins / Blue shark (Prionace glauca) off Halifax, Nova Scotia, Canada. July.

Nick Hawkins / Overhead view of a blue shark (Prionace glauca) off Halifax, Nova Scotia, Canada. July.