A middle aged, usually single or recently divorced male who has let his peer group surpass him in terms of relationship progression (i.e. his friends have found mates and settled down) while he still continues his bachelor collegiate antics of binge drinking, hitting on freshmen on Thursday's college nights at local bars and keeps a steady stocked supply of low-caliber light beers in his "beer fridge" (i.e. his college dorm room 3x3 refrigerator). Often referred to as a less-respectable, male version of a cougar.
Man, our buddy Sam is such a wildebeest. When I want to relieve the glory days and get away from family stress, I head over to his place where we pound Busch Light and eat leftover pizza- eventually heading out to the bars where he usually comes strolling home with a young 20-something at closing time.