Prehistoric Mammals

Prehistoric Mammals
Woolly Rhino:

Coelodonta is one of the most commonly represented "ice age‭" ‬mammals,‭ ‬yet surprisingly it often only gets a name mention.‭ ‬Popularly known as the woolly rhino,‭ ‬Coelodonta resembled the large African rhinos that we know today,‭ ‬but with a complete covering of fur over its body.‭ ‬This was the main survival adaptation of the woolly rhino which inhabited most of Eurasia for over 2 and a half million years. It’s uncertain exactly what kind of herbivore the whoolly rhino was.‭ ‬Some people think that it was a grazer that cropped the grass plains like a cow,‭ ‬while others believe that it was a browser that fed from low growing plants.‭ ‬Either one is plausible, ‬although most lean towards the grazing idea as grasses would have been much more abundant than more complex low growing plants. Coelodonta had a covering of fur over its body,‭ ‬something which led to the name ‬woolly rhino.‭ ‬This was the main line of defense against the cold,‭ ‬and would have trapped layers of air near the skin.‭ ‬With these layers protected from mixing with the outer air, they would be warmed by the body ‬and ‬it would have been like a blanket that slowed down the rate of heat loss from the body.‭ ‬A similar effect to this is simply wearing clothes, as these layers of fabric trap pockets of air against your body to keep you warm.‭
Prehistoric Mammals
Woolly Rhino Size and Location:

Coelodonta was a large mammal that grew to lengths of about 4-5 meters. Like modern day rhinos, the woolly rhino was robust and weighed an estimated 2-3 tons. It lived in Europe, Russia and Asia during the late Pliocene era, around 3-4 million years ago.
Prehistoric Mammals
Amphicyon:

In popular culture Amphicyon is possibly the best known of the group known as "bear dogs"‬.‭ ‬This group was named because of the immensely robust build of the body that gave them the appearance of bears even though the ‬heads were more dog-like.‭ ‬Despite this more general name,‭ ‬Amphicyon was not a true dog,‭ ‬although it did live alongside animals that were more closely related to true dogs. Amphicyon was one of the larger examples of the bear dogs. ‬It’s thought that the arrival of bear dogs in North America replaced older carnivores like Hyaenodon as the dominant predators of the land until they themselves were replaced by a combined emergence of new feline and canine predators. Although Amphicyon is thought by many to have been an omnivore,‭ ‬it still had dedicated adaptations for hunting.‭ ‬Its sheer physical size meant that it was capable of overpowering many of the potential prey ‬items that it came into contact with,‭ ‬and the especially well developed forelimbs suggest it was capable of wrestling prey to the ground.‭
Prehistoric Mammals
Amphicyon Size and Location:

Amphicyon was a large mammalian predator that grew to lengths of about 3-4 meters and weighed in at about 1300 lbs. It lived in Europe,‭ ‬the Middle East,‭ ‬Asia,‭ ‬North America and Southern Africa during the early Miocene period, about 20-23 million years ago.
Prehistoric Mammals
Deinotherium:

The two things that make Deinotherium stand out from other elephants is the two downward pointing tusks that ‬are re-curved in an arc that sees the tips pointing towards the feet when the head is carried horizontally.‭ ‬Not only is this a different direction from the forward pointing tusks of other elephants but the tusks themselves actually emerged from the lower jaw as opposed to the upper.‭ ‬The reason and function of this arrangement has baffled paleontologists since the discovery of this animal,‭ ‬in fact early reconstructions often had the jaw placed upside down so that the tusks looked like they were pointing in the right ‬direction. In elephants and mammoths the tusks are usually used as tools for the purpose of obtaining food.‭ ‬Some popular theories concerning how Deinotherium could use their tusks include digging in the ground for nutritious roots and tubers,‭ ‬hooking the tusks around tree branches where they joined the trunk and snapping them down for easier access to the leaves,‭ ‬to running the tusks down the trunks of trees to strip off the bark.‭
Prehistoric Mammals
Deinotherium Size and Location:

Deinotherium was a giant! It was between 4-5 meters tall and measured about 7 meters in length. Weight estimates are around 11 tons. It lived in Africa, Europe and Asia during the Pliocene period, about 1-4 million years ago.
Prehistoric Mammals
Cave Hyena:

As can be guessed by the name, cave hyenas are associated with living in caves (thanks sherlock),‭ ‬although they may have also taken up dens in more open areas when climatic conditions were suitable.‭ ‬By taking up residence in caves,‭ ‬cave hyenas could have sheltered from the worst of the cold conditions of the Pleistocene ice ages.‭ ‬This would have been a safer environment for them to raise young,‭ ‬as well as drag bones back from scavenged carcasses which could be gnawed upon at their leisure.‭ ‬This explains the wide variety of different animal remains that can be found in caves that had regular hyena habitation. Cave hyenas were predators and scavengers of the open plains much like their spotted African cousins are today.‭ ‬While hyenas are better known as scavengers,‭ ‬they have been well documented hunting and killing their own prey.‭ Cave hyenas have a long association with ‬Neanderthals,‭ ‬early hominids that were closely related to the ancestors of modern humans.‭ ‬One area of conflict between cave hyenas and ‬Neanderthals was competition for cave space as both used caves for shelter,‭ ‬with some areas revealing that some caves that were inhabited by cave hyenas would be taken over by ‬Neanderthals,‭ ‬to then be taken over by cave hyenas again.
Prehistoric Mammals
Cave Hyena Size and Location:

The Cave Hyena was a large predator, roughly‭ ‬1‭ ‬meter tall at the shoulders and about ‬1.5‭ ‬meters in length.‭ ‬Weight estimates for the Cave Hyena are around 500 lbs. It lived in Europe and Asia during the Pleistocene era, about 500,000 to 2 million years ago.
Prehistoric Mammals
Hipparion:

Hipparion was one of the earlier grazing horses and ‬like other ‬horses of the Miocene,‭ ‬Hipparion supported its body weight upon a single toe that ended with a hoof.‭ ‬Other toes were also present upon either side of this toe,‭ ‬but they had become so reduced in size that they did not even touch the ground. The key to fame for Hipparion is the amazing success that this genus exhibited.‭ ‬Although perhaps nothing special in terms of appearance,‭ ‬Hipparion appeared at the start of the Miocene period and continued to thrive until well into the mid Pleistocene,‭ ‬surviving for some 22 million years.‭ Hipparion would have been a horse of open plains,‭ ‬a far cry from its browsing ancestors that would have lurked among the bushes hiding from predators.‭ ‬The key adaption that Hipparion had for these habitats were high crowned teeth that were better suited for processing grasses which would have formed the most abundant type of plant that also readily replenished itself. Despite its success after the Miocene,‭ ‬Hipparion was living in a world that saw the emergence of more advanced horses,‭ ‬all the way up to the point where the modern forms began to appear.
Prehistoric Mammals
Hipparion Size and Location:

Hipparion was on the smaller end for a member of the Horse family. It measured about 2 meters in length and weighed around 1000 lbs. It lived in North America, Europe and Asia during the Miocene and Pleistocene eras, between 700,000 to 20 million years ago.
Prehistoric Mammals
Entelodon:

This thing was terrifying! Along with Daeodon from North America and Paraentelodon from Asia,‭ ‬Entelodon is one of the largest currently known "pig-like" Entelodonts. The broad distribution of Entelodon species across Eurasia reveal that it was a successful animal.‭ ‬This success may have been down to an omnivorous diet which means that Entelodon had the capability to switch and adapt to different food sources.‭ ‬Additionally the large size of Entelodon not only meant that fully grown adults were unlikely to be attacked by predators such as Hyaenodon,‭ ‬but Entelodon may have also been in a position to physically drive these predators away from their kills and feed upon the carcasses of animals themselves. This thing is nightmare fuel!
Prehistoric Mammals
Entelodon Size and Location:

Entelodon was a large mammal that grew to about 3 meters in length, was about 1 and a half meters tall and weighed around 1000 lbs. It lived in Europe and Asia during the Paleogene era, about 28-41 million years ago.
Prehistoric Mammals
Megaloceros:

Cave art from early humans depicts Megaloceros as having a dark coat of fur with a white underside,‭ ‬quite similar to other deer today.‭ ‬The art also shows Megaloceros to have had a small hump above its shoulders which has been interpreted as being for the storage of body fat for survival in lean times.‭ ‬The presence of a hump is supported by observation of the forward dorsal vertebrae on Megaloceros which have enlarged neural spines (‬bony projections that point up from the vertebrae‭) ‬that would have granted structured support for a hump.‭ ‬This hump adaptation was not unique to Megaloceros however,‭ ‬as other large Eurasian mammals such as the woolly rhino,‭ ‬and even woolly mammoths also had enlarged neural spines for supporting humps. It was originally theorized that human hunting was the cause of extinction of Megaloceros but this has since been considered not plausible.‭ ‬This is because early humans did not just suddenly appear overnight and commence a wholesale slaughter of animals. They instead evolved and coexisted for several hundred thousand years before Megaloceros went extinct.‭ ‬Although early humans almost certainly hunted Megaloceros,‭ ‬it’s extremely unlikely that after all this time they would have wiped out the species all by themselves in just a few thousand years considering that there were also other animals to hunt.
Prehistoric Mammals
Megaloceros Size and Location:

Megaloceros is one of the largest deer species that has ever lived. At the shoulders, it grew to a little over 2 meters tall and was about 3 meters long. Its weight estimates are at about 1300 lbs making it very similar in size to the modern day Alaskan Moose. Megaloceros lived in Europe and Asia during the Holocene period, about 7700-100,000 years ago.
Prehistoric Mammals
Hyaenodon:

Although Hyaenodon translates as "hyena tooth" ‬the only similarities between Hyaenodon and hyenas are the fact that they are both mammals and they both eat meat.‭ Hyaenodon was the top predator of its day with the larger forms dominating the landscape.‭ ‬Key to this success was the large head that, compared to animals today, looks too large to fit on the body.‭ ‬The neural spines of the forward dorsal vertebrae are enlarged to allow for an increased surface are for the attachment of neck muscles powerful enough to support the enlarged skull.‭ Out of all its senses,‭ ‬smell seems to have been the most important to Hyaenodon due to CAT scans that reveal a well-developed olfactory bulb.‭ ‬Include the larger skull that would have meant a nasal area with a proportionately larger surface area than a smaller animal,‭ ‬and its reasonable that Hyaenodon tracked prey by scent,‭ ‬possibly identifying which animals were sicker and weaker than the others.‭
Prehistoric Mammals
Hyaenodon Size and Location:

Hyaenodon was a large predator that lived in North America, Europe, Asia and Africa during the Paleogene era, about 20-33 million years ago. It grew to lengths of about 2 meters long and weighed in at around 1000 lbs.
Prehistoric Mammals
Megatherium:

With the possible exception of the woolly mammoth,‭ ‬Megatherium is arguably the most famous of the giant mammals that once roamed this planet after the extinction of the dinosaurs.‭ ‬Megatherium was also one of the last to disappear with remains appearing in the fossil record until as recently as the start of the Hologene,‭ ‬the period that has seen the rise of mankind and the dawn of civilization. Continuing studies about Megatherium,‭ ‬have yielded a number of theories as to its diet.‭ ‬One thing which is absolute is that Megatherium would have eaten plants and would have used its large size to reach up into trees to pick out vegetation that was beyond the scope of smaller herbivores.‭ ‬This meant that competition for food between Megatherium and other herbivores was comparatively low,‭ ‬and is one of the reasons why giant ground sloths were able to spread upwards into North America when it became connected to South America during the Pliocene era. Megatherium is believed to have had the ability to walk on its hind legs and it used this ability to reach further up,‭ ‬where it could use its large claws to pull down branches towards its mouth.‭ ‬Megatherium is also thought to have had a long tongue which it could then use to wrap around the branches,‭ ‬stripping off leaves and soft fresh growth.
Prehistoric Mammals
Megatherium Size and Location:

Megatherium was a huge mammal that reached heights of about 4 meters and weighed an estimated 4 tons. It lived in South and later on, North America during the Pleistocene era, between 10,000-100,000 years ago.
Prehistoric Mammals
American Cheetah:

Often more popularly known as the American cheetah,‭ ‬Miracinonyx is actually thought to have been descended from cougar-like ancestors. The American Cheetah displayed specialist features for a high rate of respiration.‭ ‬This includes a short face,‭ ‬with an enlarged nasal cavity that allowed for a much greater volume of air being breathed in while running.‭ ‬This would reduce the amount of anaerobic respiration in the muscles which in turn would reduce the build-up of lactic acid, meaning that Miracinonyx could run faster for longer as it pursued prey. When you do a large amount of exercise, but have to stop because your muscles are tired, it is because of a build-up of lactic acid caused by your muscles not being oxygenated fast enough. Despite these adaptations for speed,‭ ‬Miracinonyx probably could not maintain these speeds indefinitely,‭ ‬and was probably more like a sprinter than a marathon runner with bursts of high speeds over short distances, just like its modern day African cousin. ‬The American Cheetah would still have had to rely upon stealth and cunning to approach a target,‭ ‬downwind to avoid its scent being detected and low among the long grass to avoid being seen.‭ ‬Only when it was sure it was close enough to its target would Miracinonyx launch an attack.
Prehistoric Mammals
American Cheetah Size and Location:

The American Cheetah was very similar in size to today's cheetahs. It was between 1-2 meters long and weighed about 200 lbs. It lived in North America during the Pleistocene era, about 10,000-100,000 years ago.
Prehistoric Mammals
Procoptodon:

During the Pleistocene Australia had a variety of animals that loosely resemble those still living today but on a much grander scale.‭ ‬From giant 3 meter long wombats like Diprotodon to 4 meter plus goannas like Megalania.‭ ‬Procoptodon for its part was essentially a giant kangaroo. Procoptodon seems to have been one of the more abundant members of the Australian Pleistocene wildlife and seems to have been active in different habitats wherever there was ample growth of plants to support the population.‭ ‬These areas included the growth of tall plants,‭ ‬shrubs and trees that would have been out of reach for many of the animals of the time,‭ ‬and this is where the large size of Procoptodon comes in. Despite its large size,‭ ‬Procoptodon would have been prey to the larger predators of the time such as Thylacoleo,‭ ‬better known as the marsupial lion,‭ ‬that is often envisaged as dropping down from trees to hit is prey from above.‭
Prehistoric Mammals
Procoptodon Size and Location:

Procoptodon stood at about 2 meters high,‭ and it could use its long arms to reach up to 3 meters high. It lived in Australia during the Pleistocene era, about 100,000-750,000 years ago.
Prehistoric Mammals
American Lion:

African lions can run at high speed but they are not built for prolonged chases,‭ ‬and will often give up on the chase if a prey animal quickly outpaces them.‭ ‬The American lion,‭ ‬although ‬larger than the African, still had proportionately short legs that would have enabled it to reach top speed fast,‭ ‬but would have limited its ability to keep pace with longer legged animals like horses which could use their wider striding distance to run even faster.‭ ‬This means that the only way the American lion could effectively hunt was to use ambush tactics to surprise its prey so that by the time the target realized the danger it was in,‭ ‬the lion was already making its strike.‭ Like with most predators the American lion probably approached its intended victim from downwind which means the prevailing wind would blow the lions body scent away from the prey so that it did not know the lion was there.‭
Prehistoric Mammals
American Lion Size and Location:

American lions seem to have been widespread across North America with remains known from Alberta Canada,‭ ‬past the great lakes to the east coast,‭ and ‬all the way back to the Pacific coast in California around 11,000 to 100,000 years ago. American lions also crossed the Isthmus of Panama to colonize South America,‭ ‬thus taking part in the great American interchange that began ‬during the Pliocene.‭ The earlier spread of large North American predators are thought to have been responsible for displacing the terror birds from their positions as top predators from the South American landscape. The American Lion is also arguably the largest feline to ever exist. It grew to about 2-3 meters long and weighed an estimated 800 lbs.
Prehistoric Mammals
Paraceratherium:

Initially only the skull of Paraceratherium was known to science and in form it led many of the paleontologists of the day to draw similarities between it and the skull of a rhino.‭ ‬Although the fossils were not yet known,‭ ‬the rest of the animal was assumed to be rhino like upon this observation.‭ ‬The earliest reconstructions were of a large rhino like creature,‭ ‬no horn as there was no attachment point for one,‭ ‬a large heavily built body with a tough hide supported by four squat legs.‭ ‬However further discoveries gradually allowed for a more accurate construction to be pieced together,‭ ‬with the most critical discovery being that of the legs which revealed a longer,‭ ‬taller build.‭ ‬Today Paraceratherium is reconstructed as a giraffe like animal,‭ ‬but with a substantially more robust build than that of the giraffes we know today.‭ ‬Despite this analysis Paraceratherium is still more popularly regarded as being related to rhinos. ‬The large size of Paraceratherium meant that it would have been quite comfortable living the life of a high browser,‭ ‬feeding from the tree canopy.‭
Prehistoric Mammals
Paraceratherium Size and Location:

Paraceratherium remains today as the largest terrestrial ‬mammal ever known to exist. It is estimated to have reached heights of about 5 meters and measured about 8 meters in length. The weight estimates for Paraceratherium are at around 15-20 tons.

Note: I did not include Smilodon (Sabertooth) or the woolly mammoth in this post as I believe they need no introduction. As in my other posts, I like to focus on the lesser known creatures.

Edit: Hello front page! I've loved making these prehistoric posts and I hope you guys keep enjoying them. This can be my late entry for Cat Day. Send the usually asked requests.

My Other Prehistoric Posts:

Large Theropods: https://imgur.com/a/oKGjI
Medium Sized Theropods: https://imgur.com/a/Epvid
Raptors: https://imgur.com/gallery/4CVWe
Sauropods: https://imgur.com/a/UUs9iva
Ceratopsians: https://imgur.com/a/U29NBik
Ankylosaurs: https://imgur.com/a/MHb8oJf
Pterosaurs: https://imgur.com/a/hD4tS2t
Hadrosaurs: https://imgur.com/a/EqpRMQa
Stegosaurs: https://imgur.com/a/uKvjLtt
Prehistoric Marine Life: https://imgur.com/a/QtroooW

Source for prehistoric pics: prehistoric_wildlife.com and google.