 Cougars can be almost as large as <unk> , but are less muscular and not as powerfully built ; where their ranges overlap , the cougar tends to be smaller on average . Besides the jaguar , the cougar is on average larger than all felids apart from lions and tigers . Despite its size , it is not typically classified among the " big cats " , as it cannot <unk> , lacking the specialized <unk> and <unk> apparatus of <unk> . Compared to " big cats " , cougars are often silent with minimal communication through vocalizations outside of the mother @-@ offspring relationship . Cougars sometimes voice low @-@ pitched <unk> , <unk> , and <unk> , as well as chirps and whistles , many of which are comparable to those of domestic cats . They are well known for their screams , as referenced in some of their common names , although these screams are often <unk> to be the calls of other animals . 
