It may be tempting to say that tigers roar because they are big, scary cats and big, scary cats don’t meow, they roar! Well, basically that is the truth. Large cats, such as tigers and lions, use their roar for a couple of very important reasons. In the natural world they inhabit, tigers need to communicate with others in the group. They must also communicate with potential competitors, so they use their roar as a warning signal.
But tigers and their roars have one other interesting element that doesn’t seem to apply to most of the large cats of the world. Scientists have studied tiger roars very closely, using not only their own ears but also sensitive electronic equipment. Studies have focused on the pitch of the roar (frequency) as well as the loudness (mistakenly called volume) and on the length of time a big cat roars.
One of the most curious things these scientists have uncovered when studying tigers and their roars is that there are parts of the roar that humans cannot hear. This is similar to some of the high-pitched sounds that dogs hear that are outside the range of human hearing. Basically, humans can hear only a part of the tiger communication that takes place on a regular basis.
Apparently tigers have a roar that is so low in the range of sound it escapes the hearing of some other animals, including humans. Yet one study shows that this sound can penetrate solid masses such as heavy forested areas and even the hills surrounding a tiger’s area of hunting and living. In addition, this sound frequency seems to travel long distances.
So, with both the roar that humans can hear and the low-frequency sound that only other tigers may hear, the question still remains: Why do tigers roar?
We first mentioned communication between tigers. The study of low-frequency sound indicated that other tigers reacted to this level of sound, even when scientists didn’t hear it. The scientists were only able to capture the sound on sensitive instruments. But the roar, in general, is a warning to other tigers. It is one of the ways that big cats protect their territory. (They also mark territory with urine and body scent.)
Studies have also shown that a certain type of roar might be used to bring another tiger into the immediate area. This could be used to call in members of the tiger’s primary group or family. Certain types of growls have been shown to warn off competing tigers while other types of sounds are used by mother tigers to communicate with cubs.
Tigers also use some types of roaring when they court and mate, at particular times of the year. This might be combined with specific body language – ways of standing, holding the ears etc. The bottom line with tigers is that their roaring is not as random as we might believe. In fact, scientists who have studied both the lion and tiger closely believe that the tiger has a “vocabulary” of distinct sounds and levels that even the lion does not use.