Good daytime vision, enhanced cardiovascular and respiratory systems and strong bones indicate the scimitar-toothed cat was adept at driving its prey to exhaustion before making the kill.
(CN) — Scientists have successfully mapped a complete nuclear genome of the prehistoric scimitar-toothed cat Homotherium latidens — more famously known as a saber-toothed cat — and have gained vital genetic insight into the evolution of this species.
Details of this study are published Thursday in the journal Current Biology, where scientists from the University of Copenhagen discuss their findings on these notorious hunters from the Pleistocene Epoch.
“Their genetic makeup hints toward scimitar-toothed cats being highly skilled hunters. They likely had very good daytime vision and displayed complex social behaviors. They had genetic adaptations for strong bones and cardiovascular and respiratory systems, meaning they were well suited for endurance running,” said co-author Michael Westbury, Postdoc at the Section for Evolutionary Genomics, GLOBE Institute, University of Copenhagen, in a statement accompanying the study.
“Based on this, we think they hunted in a pack until their prey reached exhaustion with an endurance-based hunting-style during the daylight hours,” Westbury continued.
This time period is known to have had an abundance of predatory big cats, but the Homotherium was slightly different from other saber-toothed cats. It had the signature long upper canine teeth, but they did not reach past the bottom jaw, making them longer than a tiger’s but shorter than the infamous smilodon’s — the saber-toothed tiger. Their teeth had serrated edges for ripping into prey, but they were laterally compressed, meaning they were relatively thin and prone to breakage.
Furthermore, the Homotherium had longer front legs than the back, giving them a side profile similar to that of a hyena, and they had large nasal openings for greater respiratory capacity. This would have made them efficient hunters with impressive stamina, capable of wearing down and consuming much larger prey. They were also known to roam colder environments at high latitudes, and had flat paws adapted to provide them excellent traction in the snow.
Recently, the researchers discovered a Homotherium fossil preserved by Pleistocene permafrost outside Dawson City, Yukon Territory, Canada, and were able to obtain a DNA sample. They found that it had to be at least 47,500 years old since the commonly used radio-carbon dating method was unsuccessful, so to date the fossil they turned to genomic sequencing to piece together the creature’s genome.
The analysis showed the prehistoric feline to be very genetically diverse, as they compared the fossil’s genome with that of modern big cats like lions and tigers.
“We know that genetic diversity correlates to how many of a given species that exists. Based on this, our best guess is that there were a lot of these big cats around. This also makes perfect sense given that their fossils have been found on every single continent except Australia and Antarctica,” said Westbury.
They found the scimitar-toothed cat was so genetically diverse it is a distant relative to all living cat species today, beginning to diverge around 22.5 million years ago. This would have meant that the species was more abundant than previously thought and was able to increase its population size despite sure competition between other saber-toothed cats in the region.
The authors speculate the Homotherium’s success might also be from avoidance of other predators, the way that leopards will avoid lions despite sharing the same landscape. Regardless, their genomic analysis showed that the most favored traits, including exceptional vision, intelligence, stamina, and capacity for social behavior would have shaped them into avid hunters.
“This was an extremely successful family of cats. They were present on five continents and roamed the earth for millions of years before going extinct. The current geological period is the first time in 40 million years that earth has lacked saber-tooth predators. We just missed them,” said co-author Ross Barnett in the statement.
The authors add their study is a prime example of the benefits of interdisciplinary research and encourage future studies to utilize different areas of expertise. They were able to gain a more complete picture of the scimitar-toothed cat’s lifestyle and legacy by combining fossil data with molecular studies, and note that they hope to see this method replicated in the study of other extinct animals.
“Modern advancements within medicine and genetic research means that the sequencing methods are a lot better for us now than they were just a few years ago. On top of that, we know what specific genes are associated with in animals and humans from medical research,” said professor Tom Gilbert in the statement. “This means that we can infer a lot of things about extinct animals as we have done here. You could say that the fast progression of medical research has made this study possible.”
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