Stefan Christmann / Emperor penguin (Aptenodytes forsteri) footprints on sea ice. Atka Bay, Antarctica. August.

Konrad Wothe / Firefly (Lamprohiza splendidula) light tracks in forest, Bavaria, Germany

Nick Garbutt / Wolf (Canis lupus) male on rocky snow covered slopes. Ulley Valley in the Himalayas, Ladakh, India.

Pal Hermansen / Aerial shot of field with tractor tracks, Ski, Akershus, Norway, November 2017.

Ingo Arndt / Rear view of Horseshoe crab (Limulus polyphemus) with trail in sand, Delaware Bay, Delaware, USA, May

Ingo Arndt / Brown / Grizzly Bear (Ursus arctos horribilis) tracks on tidal flats, Alaska, USA

Ingo Arndt / Dwarf puff adder / Sidewinder snake crossing sand {Bitis peringueyi} Namibia

Ingo Arndt / Desert chameleon crossing sand leaving tracks, Namibia {Chamaeleo namaquensis}

Juan Carlos Munoz / Gemsbok (Oryx gazella) aerial view of herd on sand, Namib Desert, Namibia.

Juan Carlos Munoz / Gemsbok (Oryx gazella) aerial view of herd on sand, Namib Desert, Namibia.

Adrian Davies / Cicada turret, or chimney, formed by underground larva. Sabah, Borneo.

Anup Shah / Eastern chimpanzee (Pan troglodytes schweinfurtheii) male 'Faustino' aged 22 years walking along a track preparing to display. Gombe National Park, Tanzania.