Cheetahs Can’t Roar. What They Do Instead Is More Interesting.

There is a sound a cheetah makes that most people have never heard, because it does not appear in wildlife documentaries often enough. It is called a chirp, and it sounds almost exactly like a bird call. A high, clear, repetitive note that carries across open grassland. Mothers use it to call their cubs. Cubs use it to find each other. It is the sound of a big cat that communicates like a songbird, and it is one of several ways in which Acinonyx jubatus is unlike every other large felid on Earth.

The cheetah cannot roar. The ability to roar in big cats depends on a partially ossified hyoid bone in the throat that allows the larynx to vibrate at low frequencies. Lions, tigers, leopards, and jaguars have this structure. Cheetahs do not. Instead, the cheetah’s hyoid is fully ossified, like a domestic cat’s, which is why it can purr continuously on both the inhale and exhale, something lions cannot do. The cheetah traded the roar for the purr, and in doing so it traded one kind of communication for another.

The Speed and Its Cost

Acinonyx jubatus is the fastest land animal on Earth, reaching speeds of 112 kilometers per hour in short bursts. This is well established and widely known. What is less well known is the physiological cost of that speed and the constraints it places on the cheetah’s ecology.

A high-speed chase lasting 20 to 60 seconds raises the cheetah’s body temperature to levels that approach the threshold for brain damage. After a successful hunt, the cheetah must rest for 15 to 30 minutes before it can eat, allowing its temperature to drop. During this recovery period, it is vulnerable to kleptoparasitism, having its kill stolen by lions, leopards, hyenas, or even large groups of vultures.

Researcher Sarah Durant at the Zoological Society of London, who has studied cheetah ecology in the Serengeti for decades, has documented that cheetahs lose a significant proportion of their kills to other predators and scavengers. In areas with high lion and hyena density, this loss rate can reach 50%. The cheetah’s speed, which makes it an extraordinarily effective hunter, does not protect it from losing what it catches.

This loss rate has shaped the cheetah’s hunting strategy in ways that are not immediately obvious. Cheetahs hunt primarily during daylight hours, when lions and leopards are less active, specifically to reduce the probability of encountering competitors at a kill. They also tend to move their kills quickly after catching prey, dragging carcasses into cover before beginning to eat. Durant’s research has shown that cheetahs in areas with fewer large competitors have higher kill retention rates and better body condition, confirming that competition with other predators is a significant ecological pressure.

The Genetics Problem

In the 1980s, researcher Stephen O’Brien at the National Cancer Institute made a discovery about cheetah genetics that has shaped conservation thinking about the species ever since. Analyzing genetic samples from cheetahs across Africa, O’Brien found that the species had extraordinarily low genetic diversity, lower than virtually any other large mammal studied. Skin grafts between unrelated cheetahs were accepted without rejection, something that normally only occurs between identical twins, because the animals were genetically so similar that their immune systems could not distinguish self from non-self.

O’Brien’s hypothesis was that cheetahs had passed through a severe population bottleneck, possibly multiple bottlenecks, in the past 10,000 to 12,000 years, reducing the species to a very small number of individuals and eliminating most of the genetic variation that had previously existed. The current global population, estimated at around 7,000 individuals, is descended from that bottlenecked group.

The conservation implications are significant. Low genetic diversity means reduced ability to adapt to new diseases, environmental changes, and novel stressors. Cheetahs show high rates of sperm abnormalities, reproductive difficulties, and susceptibility to infectious disease, all of which may be consequences of their genetic uniformity.

More recent research has refined O’Brien’s original findings. Researcher Pauline Charruau and colleagues published genetic analysis in 2011 suggesting that the bottleneck may have been less severe than originally estimated, and that some genetic structure exists between African and Asian cheetah populations. But the fundamental finding, that cheetahs are genetically impoverished relative to other large felids, has held up.

The Asiatic Cheetah

Most people are unaware that cheetahs once ranged across a vast territory from Africa through the Middle East and into India and Central Asia. The Asiatic cheetah, Acinonyx jubatus venaticus, was once widespread across this range and was famously used by Mughal emperors and other rulers as hunting animals. Akbar the Great reportedly kept over 1,000 cheetahs during his reign.

Today, the Asiatic cheetah survives only in Iran, with a population estimated at fewer than 50 individuals, making it one of the rarest mammals on Earth. Conservation efforts by the Iranian Department of Environment, supported by international organizations, have attempted to stabilize the population, but the small size and fragmented distribution of the remaining animals makes recovery extremely difficult.

In Africa, cheetah populations have declined by approximately 90% from their historical range. The species has been eliminated from 91% of the countries it once occupied. Durant’s long-term research in the Serengeti, combined with range-wide assessments by the Cheetah Conservation Fund, paints a picture of a species under sustained pressure from habitat loss, human-wildlife conflict, and the illegal wildlife trade, in which cheetah cubs are captured for the exotic pet market in the Middle East.

A cat that chirps like a bird, that must rest after every kill it makes, that is genetically almost identical to every other member of its species, is running out of room. The speed that defines it cannot outrun the pressures closing in around it.