The animal kingdom is organized using taxonomy, a scientific classification system, which groups organisms based on shared characteristics and evolutionary relationships. At the level of the family, the Felidae stands out as a specific grouping of carnivorous mammals. This family encompasses all species commonly referred to as cats, ranging from the smallest wild species to the largest apex predators.
Defining the Family Felidae
All members of the family Felidae share distinct anatomical and behavioral traits. Every cat species is an obligate carnivore, meaning their natural diet consists almost entirely of meat, driven by their unique digestive physiology. This specialized diet is supported by a highly adapted dental structure, including prominent canine teeth for seizing prey and specialized cheek teeth called carnassials for efficiently shearing flesh.
The physical structure of a cat is built for stealth and precision hunting, featuring muscular, flexible bodies and a digitigrade stance, meaning they walk on their toes. A defining feature across the family is the ability to retract their claws, which keeps them sharp by protecting them from wear during normal movement. Cats also possess acute senses, including exceptional night vision and highly developed hearing, which aid in locating prey in low-light conditions.
The Big Cat Lineage
The group commonly known as the “big cats” is defined by the Panthera genus, which belongs to the subfamily Pantherinae. This lineage includes the four species known for their ability to produce a powerful roar: the Lion (Panthera leo), Tiger (Panthera tigris), Leopard (Panthera pardus), and Jaguar (Panthera onca). This distinctive vocalization is possible due to a specific anatomical feature in the throat.
Unlike other cats, these four species possess a hyoid apparatus—a set of bones that supports the tongue and larynx—that is not fully ossified. Instead, part of this structure is a flexible elastic ligament, which allows the larynx movement to create the low-frequency, resonating sound of a roar. This anatomical compromise prevents these cats from achieving the continuous, rumbling purr that characterizes most other felids. The Snow Leopard (Panthera uncia) is also a member of the Panthera genus, but it can purr and cannot produce a true roar.
The Remaining Cat Lineages
The remaining cat species belong to the subfamily Felinae, often referred to as the “small cats.” This group includes the Domestic Cat (Felis catus) and the vast majority of all other wild cat species. The key biological distinction for this subfamily is a fully ossified hyoid apparatus, a rigid bone structure that anchors the larynx closer to the skull. This solid structure allows for the rapid vibration of the vocal folds to produce a continuous purr, a sound made both on the inhale and the exhale.
This subfamily contains some of the largest, most powerful cats, yet they are still grouped with the small cats because they cannot roar. The Puma (Puma concolor), also known as the cougar or mountain lion, is a prime example, being the fourth-largest cat species overall but a member of the Felinae. The Cheetah (Acinonyx jubatus) also belongs to this group, distinguished by its unique claws, which are semi-retractable and function as permanent traction spikes for high-speed chases.
Other diverse members of the Felinae include the four species of the Lynx genus, such as the Bobcat and the Eurasian Lynx. These are characterized by their short tails and tufted ears. The Felinae subfamily encompasses over 30 species, representing the evolutionary breadth and ecological success of the cat family across the globe.