00:00You are much more Neanderthal than you think, at least as far as your DNA is concerned.
00:06These ancient hominids were no more cunning and more robust than today's humans.
00:11They made stone tools, mastered fire, wore clothes, and practiced certain specific rituals.
00:18The official theory would like them to be extinct 40,000 years ago.
00:22However, a new study suggests that it is likely that the Neanderthals were never completely extinct,
00:28but rather merged with modern humans.
00:30It would seem that every current human being has about 3% of the Neanderthal genome in its DNA.
00:36If this is true, it would indicate that the Neanderthals were much more linked to our ancestors than we thought,
00:43sharing with them a long history of cohabitation.
00:46The Neanderthals were close relatives of modern humans,
00:50but our lines separated about half a million years ago.
00:53More than 10 years ago, scientists discovered that the Neanderthals formed families with the first humans who left Africa.
01:01As a result, the populations living today outside Africa have about 1 to 2% of Neanderthal DNA in their genetic heritage.
01:10To date, we have only three truly conclusive examples of complete genetic codes from these ancient hominids.
01:18The first comes from bones discovered in a cave in Croatia, dating from 50 to 65,000 years.
01:23The other two examples, aged about 80,000 and 50,000 years, were found in two caves located in Eurasia.
01:30Scientists are not yet sure how the DNA of modern humans entered the genetic alphabet of the Neanderthals
01:37due to the lack of material to study.
01:40However, by comparing the DNA of three Neanderthals with that of 2,000 modern humans,
01:45they discovered that this DNA could contain up to 3.7% of human genetic code.
01:51This would mean that in the ancient Neanderthal population, about 1 in 30 parents were a Homo sapiens.
01:59Researchers have discovered that the DNA of modern humans had integrated into the Neanderthal genetic heritage
02:04during at least two distinct periods of interbreeding between the two species.
02:09The first would have taken place 200,000 to 250,000 years ago,
02:13and the second, about 100,000 to 120,000 years ago.
02:16It is possible that other periods of interbreeding existed,
02:20but they are not observable in the DNA sequences we have today.
02:25Another recent study, which is not yet unanimous within the scientific community,
02:30suggests that the majority of the Neanderthal DNA present in modern humans
02:34would come from a single large period of interbreeding that occurred about 47,000 years ago
02:39and that would have lasted about 6,800 years.
02:42Cranes dating from almost 100,000 years ago were discovered in two caves in the Middle East.
02:46These cranes, which seem to belong to some of the first modern humans,
02:50have characteristics like more prominent archaic eyebrows,
02:54suggesting the presence of Neanderthal DNA.
02:57This could be explained by a genetic flow of Neanderthals
03:00that would be part of the period of interbreeding mentioned.
03:03The study also looked at the genetic divergences between the three Neanderthal genomes available,
03:09revealing that their population was even more reduced than previously believed.
03:13This observation could be a new proof that Neanderthals have not simply disappeared,
03:18but that they have actually merged into the genetic heritage of modern humans.
03:22Many Homo sapiens groups have left Africa
03:25and have mingled with the Neanderthals so much that they could not remain apart.
03:30In the future, researchers aim to explore the impact of modern human DNA on Neanderthals,
03:37which could shed light on the positive or negative consequences of such a mingling.
03:41Neanderthals are not our only distant ancestors.
03:45In the past, at least nine human species populated our planet.
03:49One of them, Homo habilis, nicknamed the Skillful Man,
03:53owes its name to the discovery of stone tools among its remains.
03:57This hominid lived in East and Western Africa 2.4 to 1.4 million years ago.
04:03Homo habilis was distinguished by a slightly larger brain than its predecessors
04:08and a face reminiscent of that of large apes.
04:10Homo habilis measured about 1.20 meters and had a varied diet.
04:15For a long time, scientists have considered it the oldest member of the human line.
04:20However, new dating methods have revealed that Homo erectus, another hominid,
04:26could be older and not be directly related to Homo habilis.
04:31Homo naledi, discovered in 2013 in a cave in South Africa,
04:35is an even more enigmatic member of our human family.
04:39It is the only region in the world where these remains have been found.
04:42Although they moved standing up, measuring about 1.40 meters for a weight of about 40 kilograms,
04:48they were also adept at climbing.
04:51Their brains were small and we know little about their way of life,
04:55because no stone tool or other cultural element has been discovered.
04:59However, some scientists hypothesize that they may have buried their dead and practiced the rupestre.
05:06In 2010, fossils were discovered in a cave in Siberia,
05:10but their belonging to a specific species remained uncertain.
05:13These fossils are those of the Denisovans,
05:16a group that lived between 1904 and 5,000 years BC.
05:21Although few Denisovan fossils have been discovered,
05:24DNA analysis has revealed that they were closely related to Neanderthals and modern humans.
05:30They even formed families with the first humans, especially in Southeast Asia.
05:35Due to insufficient fossils, the Denisovans did not receive distinct species names,
05:40but their genes are found in the DNA of current humans,
05:43suggesting that they could belong to our own species.
05:47As researchers deepen their studies on Denisovans and fossils discovered in Asia,
05:52our understanding of the different human species and their place in our genealogical tree could be refined.
05:59In 2003, fossils of a very small human species were discovered in a cave on the island of Flores, Indonesia.
06:07These individuals, belonging to the Homo floresiensis species,
06:12lived from 100 to 5,000 years BC.
06:15They only measured about 1 meter in height.
06:18Scientists think that they probably descend from the Homo erectus
06:22and that they have shrunk over time due to limited food resources on this isolated island.
06:28Because of their small stature, they are sometimes nicknamed the Hobbits.
06:33About 4,000 years ago, the Homo sapiens, that is, us,
06:37were the last representatives of a diversified line of human species capable of moving on two legs.
06:44The question then arises, what have become of the other species?
06:48And did we play a role in their disappearance?
06:51Some experts suggest that our survival would be due to the increased longevity of our offspring
06:58or to our better ability to adapt to climate change.
07:02Others think that we may have competed with these other human species,
07:06or even merged with them by sharing our genes.
07:09The first Homo sapiens, which appeared in Africa about 3,000 years ago,
07:13did not look like us exactly, but they were much closer to our appearance than the other hominids.
07:19They had high and rounded skulls with almost vertical foreheads.
07:24Unlike the Neanderthals, they did not have neither the thick eyebrows nor the sagging jaws found in the Homo naledi.
07:31Interestingly, they also had a chin, a unique feature among the first humans,
07:36although its function remains a mystery.
07:39Homo sapiens lived in larger groups and had a greater genetic diversity than other hominids.
07:46This extensive social organization offered many advantages, not only for health, but also for survival.
07:53The vast networks maintained across various regions acted as a net of security.
07:59In the event of a shortage, they could turn to other groups and the latter would assist them,
08:04because they would not be considered rivals, but as one and the same family.
08:09These extensive networks also facilitated the dissemination of new ideas and inventions.
08:14A large-scale simulation revealed that the later human species
08:18were able to colonize various environments thanks to these vast networks and their remarkable ability to adapt.
08:24Although the Neanderthals were very intelligent,
08:27Homo sapiens may have had a subtle intellectual advantage.
08:31Modest inventions, such as weaving and sewing needles,
08:35could have given us a decisive advantage.
08:38Scientists have discovered traces of weaving dating back 35,000 years
08:42and sewing needles dating back 3,000 years.
08:45Weaving allowed to make baskets and nets to catch food,
08:50while sewing needles allowed to make more efficient clothes and shelters,
08:55thus ensuring heat and protection, two crucial elements for survival.
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