A group of Alligators is called a pack or congregation

A group of Armadillo is called a fez

A group of Barracuda is called a battery

A group of Bears is called a sloth or sleuth

A group of Beetles is called a possi

A group of Clams is called a bed

A group of Coral is called a reef

A group of male Dolphins is called an alliance

A group of female Dolphins is called a party

A group of frogs is called an army, colony or froggery

Lots more here
http://en.wikipedia.org/wiki/List_of_animal_names