Morley Read / Slow motion clip of a Linnaeus' sipo snake (Chironius exoletus) with open mouth, part of threat display, Amazon rainforest, Orellana Province, Ecuador. (non-ex)

Pete Oxford / Sipo Snake (Chironius exoletus) head against a white background. Captive. Endemic to Mindo Cloud Forest, Ecuador.

Doc White / Arctic Grey wolf (Canis lupus linnaeus) curled up asleep, Calfiornia Wolf Centre, San Diego County, California, USA, captive

Doc White / Arctic grey wolf (Canis llupus linnaeus) California Wolf Centre, Captive, San Diego County, California, USA, October.

Doc White / Arctic grey wolf (Canis llupus linnaeus) California Wolf Centre, Captive, San Diego County, California, USA, October.

Melvin Grey / Murine Opossum (Marmosa murina) adult, Mindo area, Ecuador

Paul D Stewart / Illustration of Monitor lizard (Lacerta monitor) now known as the Nile monitor (Varanus niloticus) from J. Frid Gmelin and Carl Linnaeus (posthumous). 'A Genuine and Universal System of Natural Histo...

MYN / Andrew Snyder / Linnaeus's sipo (Chironius exoletus) Parabara, Guyana. Meetyourneighbours.net project

MYN / Andrew Snyder / Whipsnake (Chironius cf. exoletus) Parabara, Guyana. Meetyourneighbours.net project

Roland Seitre / Southern Two-toed Sloth (Choloepus didactylus) mother and young hanging in tree, Singapore Zoo, Singapore

Roland Seitre / Southern Two-toed Sloth (Choloepus didactylus) young on hanging mother, Singapore Zoo, Singapore

Daniel Heuclin / Amazonian Whipsnake (Chironius exoletus) in tree. Kaa-Lia National Park, Bolivia, August.