Alex Mustard / A young California sealion (Zalophus californianus) uses a starfish as a toy. The playful pups pick up a variety of objects as toys, including starfish, shells, and feathers, often dropping them and c...

Ernie Janes / English Springer spaniel running over beach at low tide, chasing a terrier carrying a ball, August, UK

Ernie Janes / Jack russell terrier with two teddy bears

Petra Wegner / German Boxer with puppy, 3 months, with toy

Petra Wegner / Little girl playing with Mixed Breed Dog, puppy

Petra Wegner / German Boxer with puppy, 3 months, playing tug-of-war

Petra Wegner / Two Cavalier King Charles Spaniel, puppies, blenheim and tricolour, 9 weeks, one play biting the other in ball pool

Petra Wegner / Three Cavalier King Charles Spaniel, puppies in ball pool, two blenheim and one tricolour, 9 weeks

Petra Wegner / British Shorthair Cat, kitten, 11 weeks, cream, playing with toy

Petra Wegner / Cavalier King Charles Spaniel, puppy, blenheim coated, aged 10 weeks, standing with toy

Petra Wegner / Cavalier King Charles Spaniel, puppy head portrait, blenheim coated, aged 10 weeks

Petra Wegner / Cavalier King Charles Spaniel, puppy, blenheim coated, aged 10 weeks, standing with toy

Petra Wegner / Cavalier King Charles Spaniel, puppy, blenheim coated, aged 10 weeks, playing with toy

Alex Mustard / Male Grey seal (Halichoerus grypus) playing with an orange chew toy offered by a diver, Lundy Island, Devon, England, UK. July 2010

Alex Mustard / Diver playing with a Grey seal (Halichoerus grypus) Lundy Island, Devon, UK. July 2010

Jane Burton / Baby girl aged 6 months, sitting with a Labrador Retriever, and a basket of toys. Model released

Bryan and Cherry Alexander / Dogon boy with toy gun. Mali, West Africa, 1981.

Petra Wegner / Two mixed breed dogs sittting together, both with toy ropes in their mouths.

Bryan and Cherry Alexander / Inuit boy in American t-shirt playing with toy gun. Pond Inlet, Nunavut, Canada, 1999.

Aflo / Domestic dog, Toy poodle with a cuddly toy poodle

Aflo / Domestic dog, Dalmatian jumping to catch a frisbee

Aflo / Domestic dog, Dalmatian jumping to catch a frisbee

Aflo / Domestic dog, Dalmatian with frisbee in its mouth

Aflo / Domestic dog, Labrador Retriever with frisbee in its mouth

Aflo / Domestic dog, Corgi running to catch a frisbee

Aflo / Domestic dog, Border Collie jumping to catch a frisbee

Aflo / ic-02706 Domestic kitten plays with toy under sofa {Felis catus}

Aflo / ic-04904 Golden retriever holding ball in mouth.

Jean E. Roche / River theatre, education tool for teaching for children about river conservation, France, June 2008

LYNN M. STONE / Hungarian Vizsla dog running out of surf with tennis ball, Southern California, USA

LYNN M. STONE / Hungarian Vizsla dog running out of surf with tennis ball, Southern California, USA

Mark Taylor / Brown Roan Italian Spinone puppy, Riley, 13 weeks, chewing a rawhide shoe

Mark Taylor / Jack Russell Terrier puppy, Ruby, 9 weeks, with soft toy fox

Mark Taylor / Blue-and-white Jack Russell Terrier puppy, Scamp, chewing a rawhide shoe.

Mark Taylor / Blue-and-white Jack Russell Terrier puppy, Scamp, with a rawhide shoe chew.

Niall Benvie / Two boys playing with soldiers in an allotment garden, Carnoustie, Angus, Scotland, September

Juan Carlos Munoz / Colourful macaw gifts for sale at Parque Nacional Chapada dos Guimarães, Mato Grosso, Brazil

Mark Taylor / Silver tabby chinchilla Persian male cat, Cosmos, wearing a Father Christmas hat and trying to swipe a hanging snowman toy.

Jane Burton / Young sandy lop-eared rabbit gnawing at wood nibble

Eric Baccega / Vendor at the gift shop of the Chengdu Research Base of Giant Panda Breeding and Conservation

Eric Baccega / Vendor at the giftshop of the Chengdu Research Base of Giant Panda Breeding and Conservation

Jouan & Rius / Vezo child playing on the beach with model pirogue, West Madagascar

Jouan & Rius / Young Bushman San with model car, Bushmanland, Namibia

Jouan & Rius / Young Bushman San with catapult, Bushmanland, Namibia

Eric Baccega / Group of Giant panda babies (Ailuropoda melanoleuca) aged 5 months in Wolong's nursery, Wolong Nature Reserve, China, Captive

Petra Wegner / Parson Russell Terrier running with a ball in its mouth

Petra Wegner / Blenheim Cavalier King Charles Spaniel, 5 months, playing tug-of-war

Petra Wegner / Leonberger sitting holding toy in its mouth

Colin Seddon / Hungarian Wirehaired Viszla, lying down and chewing plastic toy, UK

Colin Seddon / Hungarian Wirehaired Viszla, lying down and chewing plastic toy, UK

Jane Burton / Skewbald Mouse {Mus genus} family in a nest box

Jane Burton / Young domestic Ferret {Mustela putorius furo} playing with catnip mouse toy

Jane Burton / Two Rats {Rattus sp} playing on a flower pot (the flowerpot is used as a nest box, the coloured wedges are for gnawing)

Jane Burton / Agouti tame Rat {Rattus sp} climbing in exercise wheel

Pete Oxford / Young child learning to use a home-made walker, Daraina, northern Madagascar 2005

Jane Burton / Two Yellow Labrador Retriever pups, 6 weeks old, one sitting behind another lying and chewing on toy

Jane Burton / Golden retriever pup, 10 weeks old lying on teddy bear

Jane Burton / Ginger and white kitten lying on teddy bear between two sleeping Yellow Labrador Retriever pups, 8 weeks old

Jane Burton / Jack Russell Terrier x Collie puppy standing on hind legs playing with a toy.

Jane Burton / Sable Border Collie, 5-month pup, batting toy with her paw to make it squeak

Jane Burton / Blue tricolour Border Collie, 7-week pup, portrait with blue rope knot toy

Jane Burton / Lakeland Terrier x Border Collie puppy chewing rope knot toy

Jane Burton / German Shepherd Dog / Alsatian, 11 years old, chewing a squeaky toy

Jane Burton / Mastiff walking with rope knot toy in mouth

Jane Burton / Mixed breed dog guarding food from puppy and growling.

Jane Burton / Two Lakeland x Border Collie pups next to a brown shoe

Jane Burton / Border Collie x New Zealand Huntaway pup, play-bowing with toy, 18 weeks old

Jane Burton / Lakeland x Border Collie pup chewing the laces of a pair of shoes

Jane Burton / Border Collie pup, 10 weeks old, playing with a ball

Jane Burton / Brown Shih-Tzu cross pup with a ball and rope, 8 weeks old

Jane Burton / Lakeland Terrier x Border Collie bitch, catching a ball

Jane Burton / Two Collie pups looking out of dog basket bed, with teddy bear and brown pot

Jane Burton / Miniature Jack Russell Terrier bitch, 20-week puppy, tugging a rope knot toy

Jane Burton / Blue eyed tricolour Border Collie, 6 months old, with ball and rope toy

Jane Burton / Tricolour Border Collie lying down, head up, with a paw on a multi-coloured ball

Jane Burton / Yellow Labrador Retriever pup chewing a pink ball, 6 weeks old

Jane Burton / Dachshund-cross 12-week pups, playing with rope and ball toy

Jane Burton / Tough toys for older pups to play with and chew

Jane Burton / Sable Border Collie pup, 11 weeks old, chewing on toy in his bed in puppy crate, with toys and a chew

Jane Burton / Lakeland Terrier x Border Collie bitch, catching a ball

Jane Burton / Stray mongrel pup in his basket lying on soft toy puppy, 9 week old

Jane Burton / German Shepherd / Alsatian dog holding a ball.

Jane Burton / English Springer Spaniel dog carrying a Christmas cracker

Jane Burton / Border Terrier sitting in his crate (indoor kennel)

Jane Burton / Lakeland Terrier x Border Collie bitch, catching a ball

Jane Burton / Two Dalmatian pups playing with a toy Father Christmas

Jane Burton / Marmalade cat in defensive posture meeting Sable Border Collie pup in his puppy crate

Jane Burton / Saluki lurcher play bowing with toy between its paws.

Jane Burton / German Shepherd dog / Alsatian catching a ball

Jane Burton / Dogue de Bordeaux dog pup, 15 weeks old, lying down with paw on toy.

Jane Burton / Sable Border Collie pup, 14 weeks old, walking and carrying a ball

Jane Burton / Brown Shih-Tzu cross pup with ball and rope, 8 weeks old

Jane Burton / Two Yellow Labrador Retriever pups, 6 weeks old, one playing with a ball watching the other yawning.

Jane Burton / Two Yellow Labrador Retriever pups side by side with toy, 6 weeks old

Jane Burton / 11 month old boy playing with Patterdale x Jack Russell Terrier pup, 12 weeks old

Jane Burton / Two Yellow Labrador Retriever pups sleeping with teddy bear, 8 weeks old