Two-week-old white lion cubs at Circus Krone in Darmstadt, Germany, May 24, 2013. (AP Photo/dpa,Fredrik von Erichsen) ( Germany Lion Cubs )
Seals "Peer," left, and "Angie" at the seal station in Friedrichskoog, Germany, on May 27, 2013. AFP PHOTO / CARSTEN REHDER ( 520103712 )
Two of seven new squirrel monkeys at the zoo in Dortmund, Germany, on May 7, 2013. AFP PHOTO/ DANIEL NAUPOLD ( 519527897 )
Singer Justin Bieber's capuchin monkey "Mally," at a home for animals in Munich. German customs authorities confiscated the monkey in March 2013 after Bieber entered the country without the animal's health documents. AFP PHOTO / CHRISTOF STACHE ( 519685159 )
Tacari the mandrill, at the zoo in Dresden, eastern Germany on May 22, 2013. AFP PHOTO / MATTHIAS HIEKEL ( 519989529 )
A mongoose lemur at Bristol Zoo Gardens on May 22, 2013 in Bristol, England. (Photo by Matt Cardy/Getty Images) ( 169233507 )
A ring-tailed lemur at Bristol Zoo Gardens on May 22, 2013 in Bristol, England.(Photo by Matt Cardy/Getty Images) ( 169233329 )
Bartek, a one-year-old male Amur tiger, at the Royev Ruchey zoo, Krasnoyarsk, Siberia, May 18, 2013. REUTERS/Ilya Naymushin ( RUSSIA/ )
A two-month-old snow fox at the Royev Ruchey zoo in Krasnoyarsk, Siberia, May 15, 2013. REUTERS/Ilya Naymushin ( RUSSIA/ )
A black-bellied salamander (Desmognathus quadramaculatus) in the Citico Creek Wilderness, Cherokee National Forest, Tennessee. (NPS Handout) ( USA-AMPHIBIANS/ )
Mice peer from a loaf of bread which they hollowed out at the Inokashira Park Zoo in suburban Tokyo. YOSHIKAZU TSUNO/AFP/Getty Images ( 519592175 )
Two recently hatched cygnets sit with their mother at Abbotsbury Swannery on May 23, 2013 near Weymouth, England. (Photo by Matt Cardy/Getty Images) ( 169326314 )
Hen and chicks, Guizhou province, China, May 20, 2013. REUTERS/Jason Lee ( CHINA )
An albino baby kangaroo peers out of the pouch of its mother on May 29, 2013 at the zoo in Duisburg, western Germany. ROLAND WEIHRAUCH/AFP/Getty Images ( 520137908 )
A week-old shire foal with her mother at Cornwall's Crealy Adventure Park on May 24, 2013 near Wadebridge, England. Once a common sight in the UK, shire horses are now classed as "at risk" by the Rare Breed Survival Trust. (Photo by Matt Cardy/Getty Images) ( 169402656 )
A 100-day-old baby elephant at Budapest Zoo and Botanic Garden on May 24, 2013. ATTILA KISBENEDEK/AFP/Getty Images ( 520027496 )
Kankay cleans one of her three 6-week-old cubs at the Zoo and Botanic Garden in Budapest on May 24, 2013. AFP PHOTO / ATTILA KISBENEDEK ( 520027121 )
Tbilisi Zoo director Zurab Gurielidze with a 10-week-old white tiger cub next to the cage of its mother, Cameron, on May 29, 2013. AFP PHOTO /VANO SHLAMOV ( 520137597 )
Bengal tiger cub Tily, age 2 months, at the animal refuge La Fundacion Refugio Salvaje in La Libertad, El Salvador, May 23, 2013. REUTERS/Ulises Rodriguez ( EL-SALVADOR/ )
A shorn alpaca walks at Alpaca-Land farm in the Austrian province of Salzburg, May 14, 2013. The annual shearing is done in the spring to make the animals more comfortable for the summer months. (AP Photo/Kerstin Joensson) ( Austria Alpaca )
Month-old warthogs in Berlin on May 24, 2013. AFP PHOTO / ODD ANDERSEN ( 520024395 )
Dachshunds at the World Dog Show in Budapest, Hungary, May 15, 2013. REUTERS/Laszlo Balogh ( HUNGARY/ )
Rabbit "Tom" jumps over an obstacle during the Kanin-Hop (rabbit jump) event of the Brandenburg agricultural fair in Paaren/Glien, northeastern Germany, on May 10, 2013. AFP PHOTO / MARC TIRL / ( 519610492 )
Inuka at the Singapore Zoo on May 29, 2013, his first day in his new exhibit. The 22-year-old polar bear was the first one born in the tropics. AFP PHOTO / ROSLAN RAHMAN ( 520134593 )