The Evolution of Modern Elephants

elephants are one of the most iconic animals to currently inhabit our world and they're fascinating anatomies and behaviors makes them a favorite amongst many people but how did these creatures come to be the way they are today and just how many living species of elephant are there elephants are members of a mammalian super order called afrotheria which includes other organisms such as odd fox hyraxes and manatees and dugongs as well as several other lineages the close relationships between all these creatures is supported by both physical and genetic evidence and within afrotheria the elephants are included in a smaller grouping the order for boskie deer there are many extinct families of robust guardians such as the Dino fears the mammoths and the Gulf Affairs but here we'll be focusing on the one remaining family the elephant heads the extinct mammoths are also members of the elephant Adama Lee but there are only two general in this grouping that are actually still alive today elephants and Locke Siddhanta elephants is the genus name given to the Asian elephant as well as numerous other extinct forms such as the silhoue sea dwarf elephant and the single surviving species within elephants is elephants Maximus this species is widely distributed across the Asian mainland as well as on several islands though historically the range used to be larger physically smaller than their African relatives these animals are able to achieve lengths of up to six and a half meters as well as height of about 3 metres of the shoulder and around five tonnes in weight other characteristics that distinguish them from the elephants found in Africa include the size of their ears which are far smaller the shape of the forehead and the number of nails on the feet since Asian elephants have five on the fore feet and four on the hind feet as opposed to the African bush elephant which generally have four nails on the front and three on the back though the forest elephant can have the same arrangement as the Asian elephant Asian elephants also possess just one finger like process on the tip of the trunk whereas African elephants have to going down to even smaller taxonomic rankings there are three subspecies of Asian elephant and one population that may be a distinct subspecies though it has not yet been officially recognized as such the largest of these subspecies the sri lankan elephant elephants Maximus Maximus today only inhabits various fragmentary areas on the island of Sri Lanka these animals can be distinguished from other subspecies by the overall darker coloration as well as the larger more distinctive areas of deep pigmentation which appear as pink patches of skin then there's the Indian elephant elephants Maximus indicus which is a very widespread subspecies spanning across many mainland Asian countries including India China Vietnam and down into the Malay Peninsula Indian elephants are lighter skins than the Sri Lankan subspecies and have smaller patches of deep pigmentation these creatures are also fairly generalist animals living in both grasslands and forests and herds move over very large areas of land the next subspecies is the Sumatran elephant elephants Maximus Sumatran owes a critically endangered tax on that today survives in fragmented populations on the island of Sumatra and numbers no more than 3,000 individuals the coloration of this subspecies is lighter than the others and has the least amount of deep pigmentation finally there's the Borneo elephant or the Borneo pygmy elephant the origin of which is currently not fully agreed upon there is some evidence to suggest that these animals may be descended from a captive population of perhaps Indian or Sumatran elephants that was released on Borneo sometime in the 18th century whereas another idea supported by 2003 DNA analysis suggests that the elephants are actually native to Borneo arriving there in the Pleistocene and subsequently being isolated from other populations for around 300,000 years or an alternative ideas that they may be a relict population of Java elephants that were introduced at some point since they are so genetically distinct so how did all these Asian elephant subspecies evolve and what is the overall species closest relative the genus elephants actually had its origin in Africa with the African elephants splitting off from the Asian lineage about 7.6 million years ago interestingly there was a great deal of DNA evidence demonstrating that Asian elephants are in fact more closely related to the extinct mammoths than they are to the African elephants genus and once elephants had originated in the Pliocene of Africa they moved out of the continent and into Eurasia eventually colonizing the southern part of the Asian continent and Islands and evolving into all the subspecies we can see today meanwhile the very closely related mammoth genus mammoths us spread out of Africa - moving into Europe northern Asia and eventually into North America and then down into Central America speciated into the famous forms such as the woolly mammoth and the enormous Columbian mammoth as they colonized new areas some members of the genus also found their way to various islands and dwarf species appeared as a result such as the Channel Islands mammoths descended from the Columbian mammoth and the cretan dwarf mammoths found on Mediterranean islands so what about the African elephants for a long time it was thought that the animals that inhabited Africa were all members of the same species but more recently evidence has mounted that suggests there are in fact two very distinct species of African elephant in the genus loch Siddhanta the largest of the living elephant species is the african bush or savannah elephant loch Siddhanta Africana which can achieve heights of more than 3 meters and sometimes almost 4 meters as well as a weight of over 10 tonnes in the very largest males while females are generally quite a bit smaller the bush elephants can be found all across the grass Plains and bushland of central and southern Africa though they are threatened by the continued habitat fragmentation they're facing tusks are present in both males and females of the species unlike the Asian elephant in which most females either lack tusks or may have very small ones and throughout the lifetime of the animal these structures continue to grow these organisms have many adaptations to the hot environments they live in such as wrinkly skin to increase their surface area and their famous ears which are said to resemble the continent of Africa that have a large number of blood vessels close to the skin this allows for easier regulation of body temperature by cooling the blood and when the elephants get too hot they will fan their ears to increase the airflow over them Bush elephants are relatively well studied due to the more open environments they tend to favour and they stick together in a family units of about ten females with their calves led by a single matriarch the family units can sometimes combine into huge clans numbering several hundred elephants male elephants will only join the groups during periods of meeting and are usually more loosely associated in groups of just males the other kind of African elephant is the African forest elephant suggested to be named Lok Siddhanta psychosis and they differ from the bush elephant in a number of ways perhaps most obviously these animals are generally smaller than the other African elephants reaching heights at the shoulder of around two and a half meters and 2.7 tonnes in weight though the largest individuals can approach six tonnes another distinction that can be made between the bush and forest elephants is that forest elephants have ears that are a lot more rounded and their tusks are in general much straighter thinner and shorter than the bush elephants however these structures are still incredibly strong and they're used to push through the thickly vegetated regions where these animals live forest elephants inhabit areas of Central Africa - and as the name suggests can be found living in jungle and forested environment as well as out on open plains the more diminutive size of these animals enables them to be better adapted than Bush elephants would be moving through the dense jungles but unfortunately the forest habitats they live in are under severe threat as deforestation and the effects of climate change result in these regions becoming increasingly fragmented now not only are there physical and behavioral differences between African bush and forest elephants but there's also accumulating genetic evidence suggesting that they should be classed as distinct species support for this separation properly began in 2001 when a study examines tissue samples from multiple populations of elephants and found that the genes or forest elephants are actually very different compared to those of Bush elephants the recognition of two African species gained further support in 2010 when another study which looked at the nuclear DNA sequences of all the living elephants as well as mastodons and mammoths found that bush and forest elephants are at least as distinct as asian elephants and mammoths and possibly more so with the two species having diverged from one another anytime between two and seven million years ago even more developments to do with the distinction of these animals occurred in 2016 when it was discovered that an extinct elephant it known as the straight tusked elephant paleo L'Occitane antiquus is in fact more closely related to the African forest elephant than the forest elephant is to the bush elephant before this study it was thought that the straight tusked elephant was a closer relative of the Asian elephants since its morphology more closely resembled those animals however by analyzing the genome of this species from two samples of paleo L'Occitane aged 120,000 years old it was found that they were much closer to African forest elephants on the evolutionary tree than to any other living species in this study the genomes of four woolly mammoth individuals were also used in addition to the genome of a Columbian mammoth and two American mastodons through the use of these other species genetics the study also reveals that elephant head evolution was not exactly quite as simple as had been previously thought there was a lot of interbreeding amongst all these species at various times in the distant past for example the Strait tusked elephant although being closely related to the modern-day forest elephant had actually also made it with Asian elephants and mammoths at some point since its genome contained traces of these other organisms not only that but African bush and forest elephants also appear to have interbred with one another in the past even after they had already diverged from their common ancestor genetic admixture is the name given to the presence of DNA from distinct lineages in a certain organisms genome as the result of interbreeding between different species and it's likely that this took place once Paleo laksa Don had moved out of Africa and into Eurasia where the animal would have then mated with Asian elephants and woolly mammoths this study therefore showed that elephant evolution has been a very messy complicated process with a lot of gene flow between species in the past but importantly it also states that in more recent times since about 500,000 years ago there has been almost complete isolation between forest and bush elephants and despite gene flow occurring between them at some point in their evolutionary histories and the fact that hybrids do sometimes appear today the data provides even more compelling evidence that these are distinct organisms so all this is to say that there's a lot of pretty good support for the classification of two species within Loch Siddhanta Africana and psychosis however the forest elephant is not considered a separate species by everyone the International Union for Conservation of Nature is the organization that composes the red list which is a collection of the conservation statuses of every assessed species on earth the list is used by governments and organizations across the entire world in their conservation efforts and so it's an incredibly important tool for securing the future of our planets biodiversity but the IUCN currently does not recognize the forest elephant as a unique species this is because in the African elephants lost assessment in 2008 the Assessors decided that premature allocation into more than one species may leave hybrids in an uncertain conservation status basing this statement on what a specialist research group had determined in 2003 however as is now clear from all the evidence and data that has been gathered since then the IUCN ready should update their assessment with the new science by classing these creatures into a single species it heights the true vulnerability of the forest elephant especially since work published in 2016 revealed that poaching has a more devastating effect on this species compared to the bush elephant as the populations increase at a slower rate forest elephant numbers have decreased alarmingly in recent years with an estimated 62 percent of these animals having been wiped out by poaching for ivory between 2003 and 2013 and there is a very real possibility that we could lose these animals within the next decade the forest elephant needs to be officially recognised as a separate species before it's too late and these animals with their unique genetics that tell of rich history of elephant evolution become extinct there are of course ongoing conservation efforts to preserve this species with organizations such as the African forest elephant foundation working to prevent further poaching and save the animals forest habitats and hopefully we are able to stop the decline of this unique lesser-known elephant before they are lost forever [Music] now before I end this video I just need to let you know that for the next two or three months we will be switching the Sunday videos to an every other week schedule since we all have exams coming up and we need more time to concentrate on them we didn't want to completely abandon the channel for so long though and so by doing videos every other week it allows us to still be able to make content over the exam period although the videos may end up being selected shorter than usual we'll also try to continue making seven days of science every week for as long as we can but animal of the week will probably go on hold for a while - anyway I really hope you enjoyed this video and to learn something new if you would like to find out more about our world its history and the wonderful life that surrounds us all please feel free to subscribe to the channel if you think we deserve it and if you would like to see more from us you [Music]

Channel: Ben G Thomas

Views: 218,247

Rating: 4.9461312 out of 5

Keywords: Biology, Science, Paleontology, Palaeontology, Dinosaurs, Animals, Nature, Wildlife, Ben, Thomas, Prehistory, Anatomy, Fossil, Bones, elephant, bush elephant, forest elephant, asian elephant, sri lanka, borneo, india, indian elephant, proboscidea, elephantid, mammoth, mastodon, columbian mammoth, woolly mammoth, african elephant, iucn, conservation

Id: dJQaBNTQRU8

Length: 14min 17sec (857 seconds)

Published: Sun May 05 2019