One of the most iconic sounds of the African bush is a lion’s roar. Waking up in the early morning hearing a lion calling close by conjures up high levels of excitement and the immediate urge to get out there and find whichever one was calling, hopefully while it is still calling.
Being the “King of the jungle”, it is quite fitting that his call is so impressive. However a slight correction is needed there, lions are generally not found in the jungle but rather in the slightly more open savanna.
The roar of a male lion is often a territorial call, something that is used to advertise status and whereabouts of a dominant male, should there be a rival wishing to challenge him. It may also be used as a means of communication between two members of a coalition of as to where each other are. Females reaching out to find a male to mate with or females getting in touch with members of the pride that may have been separated are also fairly common roars to hear.
Many people might have had their only exposure to a lion roaring at the beginning of any film by MGM (Metro-Goldwyn-Mayer). They start their movies with the iconic Leo the Lion roaring. Initially the lion in the motion picture just stood there and looked around, but throughout the years and the development of technicolour and audio advancements a separate audio clip was overlaid giving Leo a roar.
I’m unsure if this is true or not, but there are rumours that the sound was in fact from a tiger and not a lion in an effort to make it more fierce and captivating. Either way, if it is true, it is still difficult to the untrained ear to tell the difference between a lion and tiger call. This is due to lions and tigers being grouped into the same genus, Panthera, based on the anatomical similarities of their vocal structure and the presence of a ligament in the hyoid apparatus.
This apparatus consists of a chain of small bones, collectively called the suspensorium. These bones pass from deep in the ear on either side to further small bones at the root of the tongue and enclose the top of the windpipe. In most other cats the suspensorium is ossified, thus holding the larynx firmly to the base of the skull and limiting its movement. In Panthera, the suspensorium is unossified and elastic , allowing the larynx freedom of movement. The result is vocalisations that are much louder and in essence gives them the ability to roar.
As a lion vocalises it contracts muscles that run from the larynx to a position near the base of the rib cage. Thanks to the ligamentous epihyoideum, the free-moving larynx is pulled down the trachea towards the lungs. This ligament can stretch up to 22cm as the larynx slides back and forth during the vocalisation, lengthening the pharyngeal passage (distance from the mouth to the larynx) and allowing sound to resonate and reach much lower, deeper tones.
However this is not the only mechanism that produces the intense amplification of the sound called ‘roaring’.
Panthera vocal folds (the sound generating elements) have a large mass and therefore low frequency and when vibrating have a high acoustic energy. This resonates down the pharyngeal passage and out the wide mouth giving off the distinctive deep call that we all know so well.
Being lucky enough to see or hear a lion call, you will agree that it appears as though it requires a lot of energy. The massive contractions in the abdomen pulls the larynx down, lengthening the passage and therefore changing the pitch – just how a trombonist shifts the slider on a trombone increasing the length the sound has to travel before exiting the bell. Lions often call late at night or early morning when the air is still and cool, allowing the sound to travel much further.
Not to take anything away from the rest of the Panthera genus’ calls, I’d happily go out on a limb and claim the lion has the most distinctive of the lot.