Did sabertooth tigers growl or purr?

For as long as history has been recorded, the enigma of the mighty sabertooth tiger has fascinated us. A predominant question: what sound did this majestic creature make? Was it a powerful roar that resonated through prehistoric landscapes, or a throaty purr reminiscent of its domesticated descendants?

Scientists from North Carolina State University dove deep into the anatomy of these feline ancestors and found that the answer might not be as straightforward as previously believed.

The world of modern felines is divided between the pantherine “big cats” – the roaring lions, tigers, and jaguars – and the Felinae “little cats” that include purr-friendly species like lynxes, cougars, ocelots, and our beloved domestic cats.

Divergence from the cat family tree

Drawing the evolutionary tree, Adam Hartstone-Rose, a professor of biological sciences at NC State, points out an interesting divergence. He says, “Evolutionarily speaking, sabertooths split off the cat family tree before these other modern groups did.” Elaborating further, he remarks, “This means that lions are more closely related to housecats than either are to sabertooths.”

The vocalization debate has its roots in anatomy. Specifically, in a series of tiny bones located in the throat.

Hartstone-Rose provides some insight into this. He emphasized, “That’s important because the debate over the kind of vocalization a sabertooth tiger would have made relies upon analyzing the anatomy of a handful of tiny bones located in the throat. And the size, shape, and number of those bones differ between modern roaring and purring cats.”

While vocal sounds arise from the larynx and soft tissues, anatomists observed that the anchoring bones for these tissues, the hyoid bones, exhibited size and number variations between the roaring and purring feline groups.

Hyoid bones may be the answer

Ashley Deutsch is a Ph.D. student at NC State and a central figure in the study. She explains, “While humans have only one hyoid bone, purring cats have nine bones linked together in a chain and roaring cats have seven. The missing bones are located toward the top of the hyoid structure near where it connects to the skull.”

This observation has led to a widely held belief: given that sabertooth tigers had only seven bones in their hyoid structure, they must have roared. However, as Hartstone-Rose points out, this assumption is based on a shaky foundation.

“But when we looked at the anatomy of modern cats, we realized that there isn’t really hard evidence to support this idea, since the bones themselves aren’t responsible for the vocalization. That relationship between the number of bones and the sound produced hasn’t ever really been proven.”

Discovering the sounds of the sabertooth tiger

In their quest for clarity, the team examined the hyoid structures of nine modern felines and compared them with the 105 hyoid bones from the iconic sabertooth tiger, Smilodon fatalis.

Hartstone-Rose provides a nuanced perspective. “The anatomy is weird. They’re missing extra bones that purring cats have, but the shape and size of the hyoid bones are distinct. Some of them are shaped more like those of purring cats, but much bigger.”

One might presume that the missing bones, termed the epihyoid bones, would be the key to different vocalizations. However, the research revealed that the bones closest to them were similarly shaped across purring and roaring cats.

Intriguingly, it was the bones nearer the vocal apparatus – the thyrohyoid and basihyoid bones – that showed more variations in shape. This leads to an intriguing possibility. With these critical hyoid bones resembling those of purring cats, sabertooths might have purred rather than roared.

What the researchers learned

Despite conventional wisdom, Hartstone-Rose highlights a gap in understanding. “We found that despite what history has told us about the number of bones in the hyoid structure, no one has validated the significance of that difference.”

Based on their findings, he suggests, “If vocalization is about the number of bones in the hyoid structure, then sabertooths roared. If it’s about shape, they might have purred. Due to the fact that the sabertooths have things in common with both groups, there could even be a completely different vocalization.”

Deutsch surmises, “It is perhaps most likely that the size of the hyoids plays a role in the pitch of vocalization. Although Smilodon wasn’t quite as big as the largest modern cats, its hyoid bones are substantially larger than those of any of their living relatives, so potentially they had even deeper vocalizations than the largest tigers and lions.”

This intriguing study, featured in the Journal of Morphology, not only challenges pre-existing notions about the vocalizations of the sabertooth tiger but also reminds us of the vast mysteries of the animal kingdom that are yet to be explored.

The research was supported by NC State’s Office of Undergraduate Research, and contributions were made by Brian Langerhans, an associate professor of biology at NC State, and former undergraduate Deanna Flores.

More about sabertooth tigers

Sabertooth Tigers or Sabertoothed Cats, are iconic prehistoric predators. They are often depicted in art and movies due to their unique and impressive appearance, notably their elongated upper canine teeth. Here’s an overview of what is known about these creatures:

Not actual tigers

Despite the common name “sabertooth tiger,” these creatures are not direct ancestors of the modern tiger. They belong to a subfamily called Machairodontinae within the Felidae family.

Many species

When we speak of sabertoothed cats, we’re referring to a variety of species, not just one. The most famous of them is Smilodon fatalis, but there were others, including Homotherium and Megantereon.

Distinctive teeth

The most recognizable feature of these cats is their long, dagger-like canine teeth. These teeth could grow up to 11 inches in some species. They were likely used to deliver a fatal bite to the throat or belly of their prey.

Habitat and range

Fossil evidence shows that various sabertoothed cat species inhabited a wide range of environments across the Americas, Europe, Asia, and Africa. Smilodon fatalis, for instance, was found largely in North and South America.

Diet

These predators primarily hunted herbivores. In the Americas, Smilodon might have preyed on large mammals such as bison, young mammoths, and ground sloths.

Extinction

Sabertoothed cats went extinct around 10,000 years ago. The exact cause of their extinction is debated. However, it’s generally believed that a combination of climate change and the disappearance of large herbivores, which were their primary food source, played a role. Human hunting might have also been a factor.

Physical attributes

Apart from their teeth, many sabertoothed cats had robust builds with strong forelimbs, which they might have used to pin down prey. This physical structure suggests they were ambush predators, relying on close proximity rather than long chases.

La Brea Tar Pits

One of the most significant discoveries of Smilodon fossils is in the La Brea Tar Pits in Los Angeles. The tar pits have provided a wealth of information about these creatures, including insights into their age, diet, and injuries.

Not the only sabertoothed creatures

It’s worth noting that the sabertoothed morphology – that is, the development of elongated canines – is not unique to these cats. It’s a good example of convergent evolution, where unrelated species develop similar features. There were also sabertoothed marsupials and even a sabertoothed fish.

Social behavior

Some evidence, particularly from the La Brea Tar Pits, suggests that Smilodon may have lived in social groups. Frequent discoveries of multiple individuals together, along with healed injuries indicating individuals lived long after being seriously hurt (suggesting they were cared for), provide some hints towards social behavior.

It’s essential to approach our understanding of sabertoothed cats with a bit of caution. While we’ve learned a lot from the fossil record, there’s still much we don’t know, and some aspects of their biology, behavior, and ecology might remain a mystery.