Maxine, Patty and Happy are in their mid-30s and likely to live a very long time. But someday, their deaths will precipitate the end of their habitat - the elephant exhibit at the Bronx Zoo. The three female Asian pachyderms are in good health, but the zoo will not replace them after they die, said Steve Sanderson, president of the Wildlife Conservation Society, which runs the Bronx Zoo. Once the Bronx Zoo closes its elephant exhibit - whenever that may be - New York City will be left with no pachyderm exhibits. The elephant exhibits at the Central Park and...