Michael W. Richards / Domesticated Indian elephants (Elephas maximus) being walked to forest at end of the working day, Pench Tiger Reserve, Madhya Pradesh, India

Nick Garbutt / Close-up of foot of chained domestic Asian Elephant (Elephas maximus) Royal Chitwan National Park, Nepal.

Georgette Douwma / Pigtail macaque (Macaca nemestrina) chained as pet. Indonesia Imported from Borneo.

Thomas Mangelsen / Polar Bear (Ursus maritimus) investigating chained sled dog, Churchill, Manitoba, Canada

Roger Powell / Old Goldeneye Nestbox crafted from a log and chained to the side of a lodge to protect it from Wolverines. Kaalimaa, Pokka, Inari, Lapland, Finland

Roger Powell / Old Goldeneye Nestbox crafted from a log and chained to the side of a lodge to protect it from Wolverines. Kaalimaa, Pokka, Inari, Lapland, Finland, June.

Cyril Ruoso / Southern pig-tailed macaque (Macaca nemestrina) trained to pick coconuts, with owner, Malaysia.

Roland Seitre / Tourists posing with chained Tiger (Panthera tigris) Thailand. Captive, occurs in Asia. Endangered species.

Thomas Lazar / Ice covering old rusty chain & stone barrier, Lake Superior, Gooseberry Falls State Park, Minnesota, December.

Thomas Lazar / Ice covering old rusty chain & stone barrier, Lake Superior, Gooseberry Falls State Park, Minnesota, December.

Roland Seitre / Bearded Capuchin (Cebus libidinosus) chained up, Sajou barbu. Coquinal, Beni, Boliva.

Roland Seitre / Celebes Black Macaque (Macaca nigra) chained up and held by owner, native to Asia