Ever wonder, while cats can purr, they can never roar. And lions can roar but can they purr?
Lions, Tigers, Leopards, and Jaguars all belong to the same cat family like the very ubiquitous domestic cat but while the tame iteration can purr its way to sympathetic glory, it can't so much as let out a whimper of a roar, like its bigger avatars. Interestingly, while the ferocious cats mentioned at the top can instil fear with their bone-chilling roar, they are not blessed with the ability to generate even a faint happy purr.
Family Division
As per the main scientific classification, all the cats belong to the animal family of Felidae. It is further divided into two sub-families depending on whether they roar or purr.
Those that can purr but cannot roar are part of the sub-family called, Felinae. In fact, all the cats belong to this category except the four species mentioned at the beginning. And the — lions, tigers, leopards, and jaguars — are slotted under the sub-family of Pantherinae.
Vocal Division
All the theories that the scientists who have been studying cats — yes, that is a genuine job! – have conjured so far point to a small bone called the hyoid, situated near the larynx — the vocal cords.
Mechanism Of The Roar
It is the suppleness of the hyoid bone in conjunction with folds in the vocal cords that shape the voicing.
The cats that can roar have flexible hyoid bone as they have not ossified or hardened completely. They also have a specialized ligament which results in developing the deep roaring sound. The further this ligament stretches down, the deeper is the pitch of the roar.
It has also been seen that the roaring cats have a flatter and more square-shaped vocal cords than the usual triangle shaped ones. The square cords use lesser lung pressure and thus, project a louder voice.
All of these can power a lion's roar to register a high of 114 decibels, which is close to a human's auditory discomfort.
Mechanism Of The Purr
Cats, on the other hand, have their hyoid bone completely ossified in tandem with vocal folds that allow for air vibrations both during inhalation and exhalation, producing a soft, gentle sound that is comforting to the humans.
Contrasting the lion's register, cats can only manage thereabouts of 25 decibels at most.
Large Cats That Purr
Bobcats and cheetahs also purr, owing to their vocal anatomy being similar to that of cats, despite their size.
Vocal Exception
Flexible hyoid of snow leopards neither help them to truly purr nor to truly roar. Their softer, semi-roar is known as 'chuffing'.
