A baby saber-toothed tiger from 30,000 years ago was discovered! It still had whiskers and claws

Produced by: Science Popularization China

Author: Guo Dingge (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences)

Producer: China Science Expo

Editor's note: In order to understand the latest developments in cutting-edge science and technology, the China Science Popularization Frontier Science Project has launched a series of articles titled "Understanding Top Science Journals", which selects outstanding papers from authoritative journals and interprets them in plain language as soon as possible. Let us broaden our scientific horizons and enjoy the fun of science through the window of top journals.

In 2020, in the Sakha (Yakutia) Autonomous Republic in the northeastern corner of Russia, an archaeological team accidentally discovered a well-preserved saw-toothed tiger cub mummy specimen (DMF AS RS, no. Met-20-1).

The frozen carcass of the sawtooth tiger is about three weeks old and has short, thick, soft dark brown fur, about 20-30 mm long. The hair on the back and neck is longer than on the legs. Two rows of tentacles on the upper lip are clearly visible in the corners of the mouth, and the hair grows significantly. The skull of the specimen is moderately deformed, and the right side of the skull is well preserved. The complete skull shape is reconstructed based on the right side of the skull.

Baby Sawtooth Tiger Mummy Appearance

(Image source: Reference 1)

The ancient remains, believed to be the first soft-tissue fossils of a sawtooth tiger, have been buried in permafrost for more than 30,000 years (about 31,808 years), revealing jaw-dropping prehistoric mysteries.

On November 14, 2024, the research team published their research results in Scientific Reports under Nature, which shocked the academic community.

How was the saber-toothed tiger baby mummy discovered?

The saber-toothed tiger baby mummy was found in the permafrost in the Badiyarikha River basin in the Yakutia region in northeastern Siberia, Russia.

Yakutia is an extremely cold region, where the permafrost not only has a temperature below 0°C all year round, but also has extremely low oxygen and water content, which can inhibit the activity of microorganisms, thereby slowing down or preventing the decay of corpses. In this region, animal corpses can be quickly frozen in a short period of time, thus preserving their original physiological structure.

Frozen soil in Yakutia

(Photo source: provided by the author)

In the past, geologists working in the Yakutia region discovered frozen bodies of mammoths and woolly rhinoceroses in the permafrost, which caused a sensation.

Mammoth tusks found in the frozen soil of Yakutia

(Photo source: provided by the author)

In recent years, with the strengthening of international animal protection efforts, the control of ivory poaching has gradually strengthened, and mammoth ivory has gradually been developed into a commodity as a substitute for living ivory. A large number of mammoth ivory in the Yakutia region has been commercially mined. In this process, more and more animal carcasses have been gradually discovered, such as cave lions and brown bears discovered in recent years. The frozen carcass of the sawtooth tiger discovered this time was also discovered in this process.

Are saber-toothed tigers related to today's tigers?

Smilodon refers to the members of the Machairodontinae subfamily, which were once very prosperous, with dozens of species discovered, and were once the main body of the cat family. They parted ways with the feline subfamily of the living big cats: lions, tigers, leopards, etc. as early as 20 million years ago, so they have no direct evolutionary relationship with today's tigers.

The common feature of members of the subfamily Smilodon is that they have saber-shaped canine teeth, which includes the genus Homotherium.

Phylogenetic relationship between the subfamily Smilodoninae and the tribe Smilodon

(Photo source: Jiang Zuoqigao, 2022)

The Sawtooth Tiger was the most widespread member of the Smilodontidae subfamily during the late Pliocene and Pleistocene, and was found in Eurasia, Africa, and even the Americas. The Sawtooth Tiger was one of the saber-toothed tigers that survived to the latest stage (the other one was the very famous Smilodon, and the character Diego in the "Ice Age" movie series was this type of saber-toothed tiger), and it once met our ancestors. They got their name because of their flat, long, serrated canines, and their relatively slender body structure, with significantly elongated forelimbs and a short tail.

Restoration of a sawtooth tiger sculpture

(Photo credit: Julio Lacerda)

The saw-toothed tiger discovered in the Yakutia region is called the broad-toothed tiger (Homotherium latidens), which mainly lived in Eurasia during the Middle and Late Pleistocene.

What new discoveries did scientists make this time?

The researchers compared the young saw-toothed tiger mummy discovered this time with the same three-week-old lion cub mummy (ZMMU S-210286) and made many new discoveries.

The head shape of the sawtooth tiger specimen (A) and the head shape of the lion specimen (B)

(Image source: Reference 1)

The body size of the sawtooth tiger is larger than that of the same-age lion cubs, and the skull morphology is wider, with an enlarged premaxilla and an increased size of the mouth cleft (about 15.3%) to accommodate a wider mouth.

Sawtooth tiger skull specimen side view (A) and back view (B) and lion skull specimen side view (C) and back view (D)

(Image source: Reference 1)

The neck and forelimb muscles are hypertrophic, and skull morphology reconstruction shows a larger and longer neck than that of a lion cub;

The forelimbs are longer than those of lion cubs, but the body length is slightly shorter than that of lion cubs. This configuration of long limbs and short body means that they have the ability to move in open environments.

The front paws of a sawtooth tiger (A, B, C) and the front paws of a lion (D)

(Image source: Reference 1)

The front paws are round and almost as wide as their length, rather than the long and narrow front paws of a young lion. The wrist pads are missing, which is an adaptation to walking in the snow and low temperatures. The small and low ears are also adaptations to the cold climate.

Conclusion

The discovery of this unique specimen provides scientists with the first direct opportunity to observe the appearance and muscle structure of the saw-toothed tiger, helping to unravel the mystery of their lifestyle on Earth.

These findings not only refresh our existing understanding of the distribution range of saw-toothed tigers, but also provide us with valuable information about their early growth and development, which further confirms that saw-toothed tigers existed in Asia during the Late Pleistocene.

References:

1. Lopatin AV, Sotnikova MV, Klimovsky AI, et al. Mummy of a juvenile sabre-toothed cat Homotherium latidens from the Upper Pleistocene of Siberia [J]. scientific reports, 2024, 14: 1-10.

2.Jiangzuo QG, Werdelin L, Sun Y L. A dwarf sabertooth cat (Felidae: Machairodontinae) from Shanxi, China, and the phylogeny of the sabertooth tribe Machairodontini [J]. Quaternary Science Reviews, 2022, 284.