12 April 2012 Last updated at 02:37

Big picture: Rare Mediterranean monk seal released

After nearly two months recovering from a life-threatening illness in a rehabilitation centre in Greece, a young Mediterranean monk seal is returned to his natural environment. Fokionas, seen here just after being freed into the crystal-clear waters off the Greek Islands, is one of just 600 Mediterranean monk seals remaining in the wild. The species is one of the world's most endangered mammals.