A Cook Inlet beluga whale and calf head out in this undated photograph provided by NOAA Fisheries Service in Alaska April 8, 2011. Over 3,000 square miles of Alaska marine area will be protected as critical habitat for a population of endangered beluga whales, the National Oceanic and Atmospheric Administration's Fisheries Service announced on April 8. [Photo/Agencies]

A clouded leopard cub is pictured in this handout photograph, taken on March 31, 2011 and released on April 7, 2011, at the Smithsonian Conservation Biology Institute in Front Royal, Virginia. The cub is one of two born at the facility on March 28, 2011. [Photo/Agencies]

Members of the Household Cavalry take part in a dress rehearsal for the Major General's review, in Hyde Park in London April 14, 2011. The event took place in front of the Barracks, and involved displays of ceremonial manoeuvres, including those to be used for the Royal Wedding. [Photo/Agencies]