How Saber-tooth Cats Worked

Naturally, saber-tooth cats are known for their distinctive teeth -- two very long canines that extended well past the bottom of the jaw. These canines were about twice as thick from front to back as from side to side, so they resembled very thick, somewhat curved knife blades. In Smilodon fatalis, adults' saber teeth could measure up to 7 inches (18 centimeters) long. That's about as long as the average man's hand from the wrist to the end of the middle finger.

But the cats' teeth weren't always so big. Saber-tooth cats had deciduous baby teeth, just like people and many other mammals do. The cats lost their baby teeth, including a set of miniature saber canines, before they entered adolescence. In order to reach the necessary length, their adult canines grew at a rate of about 8 millimeters a month for more than 18 months. Today's tigers' teeth grow about this fast, but the canines of saber-tooth cats grew for a longer period of time than tiger teeth do.

The sheer size of a saber-tooth cat's canines can make it seem like eating or attacking prey would be a problem. But saber-tooth cats had the ability to open their mouths very wide to make up for the extreme length of their teeth. Smilodon fatalis could open its mouth up to 120 degrees wide. This let the cats take big bites, although, according to computerized tomography (CT) scans, they used those big bites for soft flesh, not thick bones. The cats' skulls weren't designed to handle the pressure of biting through bone. They also weren't designed to provide anchors for the amount of muscle needed to hang on to struggling prey for a long time. That's one reason why saber-tooth cats tended to aim for the throat or abdomen instead of the bonier parts of their prey.

What the saber-tooth cat lacked in jaw strength it made up in physical bulk and power. These carnivores were like sturdy, squat versions of modern lions. Their legs and bodies were short and powerful, and they had a lot of muscle mass, causing them to weigh a lot more than the average lion. While a lion might weigh up to 500 pounds (227 kilograms), saber-tooth cats weighed between 600 and 750 pounds (272 and 340 kilograms). Saber-tooth cats also lacked the long tail that today's lions use for balance. This may have made saber-tooth cats stronger but less agile than most of today's big cats. The lack of a long tail is also one reason why scientists don't call them saber-tooth tigers or saber-tooth lions.

Imagine a bulked-up lion that's lost its tail and been slightly compressed from head to rear and foot to shoulder, and you've got a pretty good idea of what the saber-tooth's body was shaped like. Its color is a whole other matter, though. So far, paleontologists haven't found any fossilized remains of saber-tooth skin or fur, so there's no solid evidence of their coloring. However, based on analysis of plant fossils from the last ice age, many paleontologists believe that Smilodon fatalis had the dappled coat of a cheetah or bobcat. This coloring would have helped the cat blend in with the vegetation that was common at the time.

Fossils have also given paleontologists a few ideas on how saber-tooth cats lived and behaved. We'll look at the evidence for a social structure among saber-tooths -- and arguments that they were solitary -- in the next section.

It's hard to know exactly how saber-tooth cats behaved because none are alive today. Paleontologists use two primary sources of information to draw conclusions about the cats' lives. One is the fossil record, and the other is the behavior of today's big cats, saber-tooths' closest living relatives.

As we discussed in the last section, fossilized bones have offered some clues about how saber-tooth cats hunted. Because of their stocky, powerful bodies, they were probably better at knocking animals down than chasing them over long distances. The shape of the cats' teeth also supports the theory that they ripped through the throats or abdomens of their prey, leading to death through loss of blood. Because of the variations in thickness, the cats' saber teeth were stronger from front to back than side to side. This meant that their teeth easily could have been broken while trying to subdue struggling prey. However, there aren't many broken saber teeth in the fossil record, it's likely that the cats killed through slashing and stabbing rather than holding on to struggling prey.

Evidence in the fossil record also suggests that the cats may have had a social structure. Some saber-tooth cat fossils have evidence of serious injuries, like broken bones and dislocated hips. However, the fossils also show that these injuries had time to heal or that the cats lived with them for a long time. Such injuries probably would have been fatal for solitary hunters. For this reason, some paleontologists suspect that healthy cats either actively provided injured cats with food or did not stop them from picking over freshly killed carcasses.

But not all researchers agree with this conclusion. Some argue that dehydration would have been a much bigger threat to injured animals than starvation, and there's no practical way for one cat to carry water to another. According to this theory, the cats may have lived off of stored fuel, like fats and proteins, while they allowed their injuries to heal.

Smilodon fatalis is probably the best-known saber-tooth cat in history, particularly in the Western hemisphere, where it lived. But it wasn't the only cat, or the only mammal, with saber teeth. Next, we'll look at some of the other animals with giant canines that have lived on Earth.

There are several reasons why many people think of the Smilodon genus when they think about saber-tooth cats, even if they're not familiar with the scientific name. One is the wealth of Smilodon fossils, which has given scientists and museums lots of material for study. Most of these fossils were found in the Rancho La Brea tar pits in California. Saber-tooth cats are one of the most common mammal fossils found in this naturally-occurring tar. However, in spite of the wealth of saber-tooth fossils found there, entrapment in the tar wasn't all that common. The fossils in La Brea accumulated over about 25,000 years.

Smilodon cats are also well known because they're the saber-tooth cats that lived on Earth most recently. They shared the planet with other familiar ice-age mammals like woolly mammoths, mastodons and ground sloths. All these animals were extinct by about 10,000 years ago due to a number of factors, including climate change, terrain change and human hunting. The Smilodon cats most likely became extinct because their primary source of food -- mammals that were larger than the cats themselves -- died out. The cats weren't fast or agile enough to catch smaller prey, leading to their eventual extinction.

Another genus of saber-tooth cat lived at the same time as the Smilodon variety. These were the Homotherium cats, which had shorter, flatter teeth. Some paleontologists describe them as scimitar cats. These cats had a slightly larger range than the Smilodon genus. Homotherium cats lived in Africa, Europe, Asia and North America. They became extinct about 11,500 years ago.

Researchers have found much older saber-tooth cats in several clay-lined caves near Madrid, Spain. Like the La Brea tar pits, these caves have provided scientists with lots of well-preserved fossil samples. The cats found there are from the genus Paramachairodus -- oldest genus of saber-tooth cats on the planet -- and the genus Machairodus. These were large cats, but their teeth were shorter than those of the Smilodon genus. These cats lived around 9 million years ago.

These are just a few of the many extinct carnivores that have evolved saber teeth. There are no saber-tooth cats alive today, but there are a few animals with dramatically long canine teeth. One example is the walrus, which uses its long tusks for everything from social displays to moving on ice. But although these are modified canines, they aren't quite the same as saber teeth because they're rounded rather than flattened from side to side. However, as living species go, they may be the closest thing you'll see to a pair of saber teeth.

Follow the links on the next page to find lots more resources on saber-tooth cats, fossils, dinosaurs and other extinct animals.

Saber-tooth cats, which are commonly yet improperly referred to as saber-tooth tigers, weighed up to 750 pounds and were built like compact lions. There are many different types of saber-tooth cats, and they existed in different time periods. Some saber-tooth cats lived 9 million years ago, while others lived on Earth up to the last ice age, which was 10,000 years ago. The more recent saber-tooth cats became extinct due to a loss of available prey. After the mastodons and other large mammals died out, there wasn't enough food to support the saber-tooth cats because they weren't fast enough to hunt the smaller animals.

Saber-tooth cats had very pronounced canines, which they used for ripping and slicing the throats and abdomens of their prey. Even though their canines were massive and intimidating, their jaws weren't strong enough to bite through bones. So, the cats had to use their canines like knives as opposed to crushing the spines of their prey. Saber-tooth cats had baby teeth, just like humans and other mammals have. After their baby canines fell out, the adult canines grew at a rate of 8 millimeters per month for 18 months. It would seem that having such enormous teeth would make biting and chewing rather difficult, but saber-tooth cats' jaws could open up to 120 degrees wide, enabling them to use the canines more precisely.

There are differing views regarding saber-tooth cats' social behavior, and, because they are now extinct, we may never know the truth. Some paleontologists believe that they were social cats that hunted in packs, while others believed them to be solitary stalkers of prey. Scientists have found saber-tooth cat fossils that displayed serious injuries, though the injuries appeared to have healed over time. Many scientists believe that such fossils could not exist unless healthy saber-tooth cats looked after the injured ones. However, other scientists believe that those fossils came from cats that lived off stored fats and proteins while their injuries healed.

Top 5 Saber-tooth Cat Facts

­­­­­Learn more about saber-tooth anatomy.

Learn more about saber-tooth anatomy.

Learn more about how saber-tooth cats worked.

Learn more about how saber-tooth cats worked.

­Click here to learn about the fossil evidence which indicates that there may have been social saber-tooths.

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