Polar Bear

Twin polar bear cubs stand with their mother Giovanna in their enclosure at Tierpark Hellabrunn in Munich...Twin polar bear cubs stand with their mother Giovanna in their enclosure at Tierpark Hellabrunn in Munich, March 19, 2014.  The 14 week-old cubs, who made their first public appearance on Wednesday, have yet to be named.      REUTERS/Michael Dalder (GERMANY  - Tags: ANIMALS SOCIETY)

Michael Dalder/Reuters

Twin polar bear cubs stand with their mother Giovanna in their enclosure at Tierpark Hellabrunn in Munich. The 14-week-old cubs, who made their first public appearance on Wednesday, have yet to be named.

A polar bear named Nanuq is seen through the glass wall of the basin of his enclosure diving for an ice cake made of frozen fish, meat and fruit in the zoo in Hanover, Germany.

Christophe Schmidt/EPA

A polar bear named Nanuq dives for an ice cake of frozen fish, meat and fruit in the zoo at Hanover, Germany.

Luka, almost two-year-old male polar bear, swims in his new home at the zoo in Wuppertal, Germany. He was born in the Netherlands and is meant to be the play partner for female polar bear Anori who is the same age.

Roland Weihrauch/EPA

Luka, an almost two-year-old male polar bear, swims in his new home at the zoo in Wuppertal, Germany. Born in the Netherlands, Luka has moved to Germany to be a companion for female polar bear Anori, who is the same age.