Four words have been given, out of which three are alike in some manner and one is different. Select the word that is different.

Prowl Growl Howl Yowl

Prowl

Except 1(prowl) all are related to sounds Prowl - an act of moving restlessly in search of prey Growl - make a low or harsh sound Howl - weep and cry out loudly Yowl  - make a loud cry