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Child’s tooth discovery provides clues to extinct, mysterious group of humans

Donna Coutts, May 25, 2022 7:00PM Kids News

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The discovery of a Denisovan tooth in Laos shows they lived across a much wider area than previously known and adapted to different climates, as illustrated by this Kids News map. Picture: Abi Fraser media_cameraThe discovery of a Denisovan tooth in Laos shows they lived across a much wider area than previously known and adapted to different climates, as illustrated by this Kids News map. Picture: Abi Fraser

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Scientists have found a child’s tooth from a prehistoric*, extinct type of human cousin called Denisovans.

The molar* is thought to have belonged to a girl probably aged three-and-a-half to eight-and-a-half years old. The tooth hadn’t yet erupted, or broken through her gum.

It was found in a cave in Laos in Southeast Asia, nearly 4000km from where other Denisovan (pronounced den-eess-e-ven) remains* have been found.

Ancient human tooth discovered in Laos cave

Because Laos is humid* it’s difficult to get DNA* from the tooth. Scientists knew it was from a Denisovan from its enamel* coating and because it is short and has lots of wrinkles on its surface.

A close up of the tooth from a ‘birds-eye’ viewpoint. Picture: Fabrice Demeter (University of Copenhagen/CNRS Paris media_cameraA close up of the tooth discovered in a Laos cave. Picture: Fabrice Demeter/University of Copenhagen/CNRS Paris

Studies of other objects (such as teeth of ancient animals including giant elephants) found in the same level of sediment* in the cave led scientists to believe the girl lived between 164,000 and 131,000 years ago.

Very little is known about Denisovan people. Before the Laos find, evidence of the Denisovan people was from just three teeth and a little piece of bone from a pinky finger found in a cave in Siberia in 2010 and a lower jaw found in Tibet. The teeth have been dated as between 195,000 and 52,000 years old and the jawbone as 160,000 years old.

Inside Ngu Hao 2 cave showing the concreted remanent cave sediments adhering to the cave wall. The overlying whitish rock is a flowstone that caps the entire deposit. Picture: Fabrice Demeter, University of Copenhagen/CNRS Paris media_cameraThe inside of the cave shows remnant sediments adhering to the cave wall. The overlying whitish rock caps the entire deposit. Picture: Fabrice Demeter/University of Copenhagen/CNRS Paris

Both these places are freezing, whereas* Laos has a tropical climate.

The Laos find shows these people could adapt* to a range of climates and that they lived across a larger area than previously known. The Laos cave is about 3800km from the Siberian cave.

The Laos tooth was found and studied by a team of Australian and international scientists. The results of their research are published in the journal Nature Communications.

Mike Morley, who leads the Flinders University Microarchaeology Laboratory, holding a slice of sediment on a slide. Picture: Mike Morley, Flinders University media_cameraThe Laos tooth was found and studied by a team of Australian and international scientists, including Flinders University Associate Professor Mike Morley, seen here examining a slice of sediment on a slide. Picture: supplied

MEET THE DENISOVANS
Denisovans are named after the Denisova cave where the first remains were found in Siberia, in Russia.

Like modern humans, they are part of the Homo genus. Genus is the level of scientific naming above species.

Three Homo species are known to have lived in the Denisova cave: Homo sapiens (modern humans), Homo neanderthalensis (Neanderthals, pronounced nee-anger-thals)) and Denisovans, which doesn’t yet have a scientific name. The three species have the common ancestor* called Homo erectus.

Top, bottom and side views of the tooth discovered in Tam Ngu Hao 2. Picture: Fabrice Demeter, University of Copenhagen/CNRS Paris media_cameraTop, bottom and side views of the tooth discovered in Tam Ngu Hao 2, called “Cobra Cave” by locals. Picture: Fabrice Demeter/University of Copenhagen/CNRS Paris

Denisovans lived at the same time as Neanderthals and were in the cave during the same time in history. Scientists know from DNA from a bone found in the Denisova cave that Neanderthals and Denisovans mated.

Scientists also know from studying modern humans’ DNA that all three species are related. There is Denisovan DNA that has been passed down through generations to some modern humans. Denisovans became extinct about 20,000 years ago.

media_cameraMeet the Denisovans! Not much is known about this species, but DNA shows modern humans, Neanderthals and Denisovans are all related. Our Kids News map shows the location of the different remains recovered so far. Picture: Abi Fraser

IN THE COBRA CAVE
Locals call Tam Ngu Hao 2 cave where the tooth was found Cobra Cave.

The cave is in northeastern Laos in the Annamite mountains.

FAST FACTS

  • The tooth belonged to a Denisovan girl thought to be aged between three and eight years old
  • Denisovans are an extinct species related to modern humans and Neanderthals
  • Testing of animal teeth and sediment found around the molar helped scientists date it as between 164,000 and 131,000 years old
  • It was found in a cave in the Annamite mountains in northeastern Laos, in Southeast Asia
  • Before this tooth was found, the Denisovan species was only known from finds in Siberia and the Himalayas

GLOSSARY

  • prehistoric: before recorded history
  • molar: a grinding tooth at the back of the mouth
  • remains: a body or parts of a body after death
  • humid: warm and wet weather
  • DNA: the carrier of genetic information in living things
  • enamel: hard shell of a tooth
  • sediment: material that settles to the bottom of liquid
  • fragment: small piece
  • whereas: in comparison with the fact that
  • adapt: change over time to suit the conditions
  • ancestor: a relation who lived a long time before
  • sedimentary: describing rock that has formed from sediment settling to the bottom of liquid
  • evaporates: liquid that turns into a vapour; dries up
  • artefacts: human-made items from history

EXTRA READING

Ancient jawbone solves mountain puzzle

Meet our mysterious lost ancestors

First look at humans’ ancient cousin

Oldest fossil of early human species is discovered

QUICK QUIZ

  1. What is a Denisovan?
  2. What type of tooth was found?
  3. Why is it difficult to get DNA from the tooth?
  4. How far was the tooth discovery from other known Denisovan remains in Siberia?
  5. How old are the Siberian teeth and jaw estimated to be?

LISTEN TO THIS STORY

CLASSROOM ACTIVITIES
1. Describe a day
What do you think a typical day for a Denisovan kid living in Laos would have been like? Use your imagination and information in the story to write your description.

Time: allow 25 minutes to complete this activity
Curriculum Links: English; Science; Critical and Creative Thinking

2. Extension
What do scientists need to find to learn more about Denisovans? List five things that you think could help us to understand important facts about their way of life. Next to each item in your list, write sentences explaining why each one would be an important find.

Time: allow 15 minutes to complete this activity
Curriculum Links: English; Science; Civics and Citizenship

VCOP ACTIVITY
To sum it up
After reading the article, use your comprehension skills to summarise in a maximum of three sentences what the article is about.

Think about:

What is the main topic or idea?

What is an important or interesting fact?

Who was involved (people or places)?

Use your VCOP skills to re-read your summary to make sure it is clear, specific and well punctuated.

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