Polar bear cub Knut walks in an enclosure in Berlin zoo April 9, 2007. Knut, born on Dec. 5, 2006, had to be hand fed by a zoo employee after its mother Tosca refused the baby. The deadline for deciding whether to list the big white bears as threatened under the Endangered Species Act is Wednesday but Dale Hall, head of the U.S. Fish and Wildlife Service, told reporters on January 7, 2008, it would take as much as a month more to analyze all the information. Environmentalists vowed to sue for quicker action. [Agencies]