The Mammals that Lived Alongside the Dinosaurs

mammals have been around for a really long time predating birds snakes and possibly even lizards however it wasn't until 65 million years ago they started to get any larger than a dog or branch out into very diverse niches this is because they lived in a world dominated by dinosaurs and wouldn't be able to get a foothold until they died out despite this mammals have lived alongside dinosaurs for a huge swath of geological history in fact they have lived in dinosaur habitats for the majority of their existence they would go on to adapt into many niches making them arguably just as diverse as the dinosaurs they shared their habitat with the most widely used classification for the first true mammal is the common ancestor of the three groups of mammals alive today monotremes marsupials and placentals there were animals that exhibited the mammalian traits of producing milk and at least partial warm-bloodedness since the late triassic but they are known as Mammalia forms the common ancestor of monotremes and placentals and the first true mammal is unknown it probably existed right at the end of the Triassic or right at the beginning of the Jurassic about 200 million years ago during the Triassic the ancestors of mammals called cynodonts occupied many niches with some of them being the size of dogs however pressures caused by the proliferation of dinosaurs and their relatives forced the ancestors of mammals to get smaller because they were unable to compete for the larger niches because of this by the time mammals evolved they were rarely larger than a rat and we go on to fill many niches that small animals fill and dinosaurs didn't dominate in addition they would adapt to many lifestyles such as being nocturnal that allow them to avoid the large predators that were patrolling during the day a theory called the nocturnal bottleneck argues that these adaptations may explain many common features seen all across the mammalian group to this day mammals more often than not have superior hearing and smell than birds and reptiles which are useful traits for finding prey or food in the dark their fur offers the better insulation for living in the holder environment of the night finally with the exception of primates mammals usually lack color vision and have less accurate eyesight than birds and rats cause which are unnecessary for living in the dark during some point to the Mesozoic mammals were almost unanimously forced into nocturnal niches causing a genetic bottleneck for these adaptations as the mammals today are descendants of nocturnal ancestors they've retained these features and less selective pressures caused them to evolve in an opposite direction so the notes our bottleneck theory argues that mammals are still shaped by living alongside the dinosaurs at one point by a hundred and sixty-five million years ago during the mid Jurassic agility codon was pioneering a new method of life that would help avoid the dinosaurs being one of the first mammals to make home in the trees the specimen of this creature showed key similarities with the current tree dwelling mammals specifically in their limbs pointing towards an arboreal lifestyle some have argued that a few dinosaurs may have had climbing abilities but by and large dinosaurs don't seem to have mastered a poriyal lifestyles the same way that mammals have this shows that evolving to live in the trees would have been very beneficial in keeping them out of harm's way as mammals were known to have evolved for life in the trees pretty early on the next step would seem to have to be taking to the skies and amazingly just like sugar gliders or flying squirrels today there were ancient gliding mammals that lived alongside the dinosaurs the most well-preserved of these was known as valachia to theorem that lived in the Late Jurassic 164 million years ago I had Griffing hind legs suggesting a head evolved from a boreal ancestors and was a tree dweller itself interestingly all the gliding mammals today are herbivorous the velociter theorem was thought to be insectivorous making them truly unique animals however some scientists have pointed out their insect every may have meant they were not glide as a tool and were actually capable of powered flight in addition to that diet they had specialized femurs similar to bats that would help them deal with flying stresses and their membranes stretched across their digits as well as their limbs all of these features pointing to a capability of powered flight a relatively close relation of illicit etherium called egg theory Connaughton has also been suggested as a flying animal rather interestingly their remains have been found in marine deposits found near the remains of sharks and sea turtles suggesting they perhaps lived in a marine environment and their teeth show similarities with vociferous creatures meaning they may have fed on fish although the evidence to know for sure is lacking if these creatures could indeed fly it would mean there is a fifth lineage of flying animals down to the bats pterosaurs birds and insects the latest of theory in a minute Theo con Adan belonged to a whole group of gliding and possibly flying mammals called filitosa tyranny that have been found in several continents throughout the world living for about 40 million years this shows that gliding mammals could have possibly played an important role in many dinosaur habitats around the world some animals also have some uniquely mammalian defenses on their body that they were able to adapt specifically from being covered in fur as one small creature called spinal estie's had hairs on their body that had been reinforced with keratin spinal estie's was the first perkily mammal it wouldn't have looked like a modern-day Hedgehog or porcupine and probably resemble a bristly rat however these adaptations would have made them less appetizing and harder to eat framing mammals is nocturnal burrowing animals or tree climbers avoiding their saurian oppressors may not always be fair though as there were many that did not live like this for instance there was at least one mammal that fed on dinosaurs Reaper named Amos lived about 125 million years ago in what is modern day China and one of the specimens was found with a small theropod dinosaur in its stomach Reaper named Amos was about the size of a badger making it one of the largest Mesozoic mammals so it could have been quite capable of hunting small dinosaurs however it could not be known if they actively hunted them or they were discouraged as mentioned there were many mammal like animals they existed in the wider Mammalia form group that lived before the common ancestor of the currently living mammals some of these non mammal Mammalia forms survived went into the Jurassic and although most of them lived similar to the mammals at the time some had diversified into some new territory cast Eric Alda was a semi-aquatic animal highly specialized to this lifestyle sharing characteristics with beavers and authors its most obvious feature was as large beaver looking tail and in fact his name means beaver tail there was also a semi-aquatic mammal that lived during the Cretaceous called stafford on stereo tom was a very distant ancestor of monotremes the egg-laying mammals which is very identifiable as they probably look very similar to the platypus monotreme evolution and in particular when they split from other mammals is hotly debated but it is known to have happened really long time ago perhaps even in the triassic five of the Mesozoic mammals I have talked about agility code on the latest etherium ik Thea canard on spinal estis and repin amoebas belonged to a large group of mammals that have no living Representatives called Utrecht owner dontoh the central mammals and marsupials are more closely related to this group than they are to monotremes showing how distant the relation is these differences are also shown in their anatomy as monotremes have many primitive features like reptilian esque sprawling limbs and although they are warm-blooded their metabolism and body temperature is lower than most mammals it's not to mention the egg-laying although it is poorly understood exactly when it happened one group of mammals split into the two groups met atheria and youth area about 160 million years ago minta theory would eventually go on to become marsupials a new theory would eventually go on to become for central mammals in contrast to today during the Cretaceous in North America and perhaps other continents metatheory actually outnumbered the placentals and were more successful metatheory ins occupied many niches including one small cat-like animal called died alfred on the probably specialised in eating freshwater prey like mollusks and crabs they lived right up to when the dinosaurs died out and even shared a habitat with t-rex died out for don't want true marsupials though they would have reproduced in a similar way to modern-day marsupials who were not closely related to any living species these non marsupial metatheorem survived the extinction that wiped out the dinosaurs and lives alongside all the other mammal groups only dying out fairly recently one of the last surviving groups being the spirited ons that lived in South America and only died out a few million years ago true marsupials are categorized as being the last living common ancestor of the living marsupials the vast majority of living marsupials live in Australia of course but a smaller number of them live throughout the Americas and these two groups separated before the dinosaurs died out both the surviving lineages the opossum is the only marsupial found north of Mexico however opossums have remained virtually unchanged for almost 70 million years so you ever see opossum remember that very similar creatures once lived alongside the dinosaurs the earliest eutherian or the earliest mammal table percenter was probably Jeremiah although this is not set in stone as there are other contenders and is an adaptation that is difficult to spot from looking at fossils huge numbers of mammal species went extinct during the KT extinction however they did fare better than nearly all the other animals whereas only a handful of lineages survived from each of the other groups of animals many different mammal groups survived the KT extinction an addition to these a few other mammal groups survived the KT extinction event to then go on to go extinct during the Cenozoic so perhaps the adaptations that mammals evolved to live alongside the dinosaurs helped them to survive when the non-avian dinosaurs did not a massive thank you to korean for their support and patreon if you'd like to join them in supporting me then you can go to patreon.com/scishow and consider subscribing thank you for watching [Music]

Channel: Moth Light Media

Views: 573,815

Keywords: dinosaurs, dinosaurs mammals, mesozoic ammals, mammals, prehistroic mammals, evolution of mammals, eveolution, cute, cute mammals, placentals, marsupial, monotreme, reponamamus, volaticotherium, ichthyoconodon, agilodacodon, mammalian, basal mammals, mammaliaform, genetic bottle neck

Id: CaPVvSgU7ko

Length: 9min 54sec (594 seconds)

Published: Sun May 19 2019