a group of meercats is called a mob or gang.
http://www.wildkingdom.com/games/meerkatmunchies.html

The most commonly accepted phrase for a group of ferrets is
"a business of ferrets". Some people spell it "busyness" instead

A group of ferrets is called a business, fesnyng or fesynes.

http://www.americanhumane.org/kids/groupnames.htm

http://www.funtrivia.com/en/Animals/Animal-Groups-5340.html
A dray is a group of squirrels