Hedgehogs great and small – in pictures

A hedgehog crossing the road … increasingly busy roads are one of the main reasons for the falling numbers of hedgehogs in Britain Photograph: Kirsty Wigglesworth/PA

Gardeners' use of slug pellets is another threat Photograph: Alamy

A hedgehog hibernating … hogs that weigh under 600g might not survive the winter Photograph: Arterra Picture Library/Alamy

Whereas this overweight hedgehog had to be put on a diet Photograph: Solent News/Rex Features

Hedgehogs have been known to scale walls and even appear in first-floor bedrooms Photograph: Niall Benvie/Corbis

Hedgehogs have around 5,000 spines to protect them Photograph: Julian Stratenschulte/AFP/Getty Images

Some claim that hedgehogs can travel 12 miles in one night – though this pygmy hedgehog probably wouldn't make it so far Photograph: David Northcott/Corbis

It is not a good idea to give hedgehogs milk – they are lactose intolerant Photograph: Nils Jorgensen/Rex Features

Apparently it is illegal to drive hedgehogs through the state of Pennsylvania Photograph: Juniors Bildarchiv/Alamy

A baby lesser hedgehog tenrec at Edinburgh zoo Photograph: David Cheskin/PA