The major difference between a martingale collar and a normal collar is that the former has two loops. One of the loops is for adjustment purposes, and the other one provides extra control when a lead is attached. Also, a martingale collar is wider and thicker than a normal one. There are differences in the way the two collars function as well. While a normal collar slackens when a dog pulls away from it, a martingale collar will hold on tight in an almost-chocking manner until the pet relaxes.