Sorry this took so long! I was hoping to get this done by Halloween,
but it took a week to get this one out. Next time I’ll do monster posts like
this one in installments. Today we’re going for another lighthearted one-yes,
we’re going to do a top ten list today. This one’s been inspired by the
documentary series Sea Monsters, where host Nigel Martin took the audience
through the “top 7 deadliest seas”. In the same spirit, I’ve chosen the top 10
Deadliest Terrestrial faunas, based on the number of large predators. If I
missed any that deserved to be on this list, please let me know. This isn’t
based on any particular grade, but based on the number of large predators
present in the fauna.
#10
First, we’ll go to Texas, in the Sakmarian age,
about 290 million years ago. The environment consists of low, open wetland,
like river deltas today. There’s a great variety of aquatic life and vegetation
that can support a large variety of wildlife. These were the first big land
animals. Now, in terms of predators ,you could divide them into three
areas-terrestrial, amphibious, and aquatic.
In the terrestrial realm, we’ve got Dimetrodon. Yep,
that classic pelycosaur that people think is a dinosaur. It’s got nasty teeth
and a huge sail on its back, but more related to whoever’s reading this (even
if it’s an office cat) than a dinosaur. They were calculated to get up to 500
lbs and 14 feet long. Body was fairly low to the ground, but that’s also true
of monitors and crocodilians, and they’ve killed people quite brutally.
Predator #2 is Sphenacodon, which is a smaller
version of Dimetrodon with a much lower sail. The distribution of fossils
suggests that the Dimetrodon preferred the wetter east while the Sphenacodon
was found in the drier west. The head’s very similar-slicing incisors, large
canines, and a battery of smaller slicing teeth along the side, a heterodont
dentition similar to modern mammals
In the amphibious realm, we’ve got a third big
pelycosaur (primitive ancestors of mammals). The body is long and heavy,
roughly the same as Sphenacodon and Dimetrodon, but the skull is deeper and
longer. What makes this animal different is the teeth-the name Ophiacodon is
Greek for snake teeth. These teeth weren’t
broad sabers like in Dimetrodon, but narrower and pointed for catching fish,
small reptiles amphibians, and large insects. Not quite as formidable as
Dimetrodon, but still a powerful predator
The other amphibian is actually an amphibian. You
should recognize this one-big broad head with eyes on the top, fat wide body
with armored skin and short tail, and many long sharp teeth, with huge curved
fangs on the palate. This guy is
Eryops-a bit of a combination of frog, crocodile, and salamander. Besides Dimetrodon,
it’s an iconic Permian predator. The chest and hips had evolved to support its
weight on land, but the small limbs point to a very slow gait and an aquatic
habitat, something like a snapping turtle or crocodile today. While half as big as the pelycosaurs, a
2-foot skull full of teeth is nothing to sneeze at.
In the water, things don’t improve. There’s
Archeria, a salamander-come-muskellunge the size of a sea lion related to my
old friend Diadectes. And there’s Orthocanthus, 10 foot, double-fanged
moray-eel-shaped sharks that prowled freshwater rivers, lakes and streams.
Neither would be a great white or saltwater crocodile in proportions, but if
you’ve seen an episode of River Monsters, you’d have a feeling of what kind of
big nasty aquatic predators existed in the Permian.
#9
Our second
fauna is South Africa, part of the Karoo beds. This is the Wuchiapingian era,
transitioning from the middle to the late Permian. In this period, it is therapsids (basal
synapsids, ancestors of modern mammals and their relatives) that rule the
earth.. The biggest is the tubby omnivore Jonkeria, up to 15 feet long. The
long skull has large canines and
incisors, capable of shearing off both flesh and plant material. Think of a
giant pig or hippopotamus. Pretty
formidable animal, but it isn’t the apex predator of the time.
There is a
faunal turnover at the time-big headed dinocephalian (like Jonkeria) predators was
being replaced by saber-toothed predators called gorgonopsids. Dinocephalian
predators include Anteosaurus and Titanosuchus. Anteosaurus has a long body,
short limbs, and a huge fanged head. Titanosuchus is slightly older and
smaller, but has the very similar body
plan. These animals have thickened skulls, suggesting head-butting as a social
activity.
A more
primitive but still large predator group is the Biarmosuchids. The last and
largest is present. The crest-headed Lophorhinus is smaller than the other
predators, but still the size of a bull terrier and a formidable, big-toothed
predator.
The most
successful group consists of newcomers. These are the gorgonopsians. They’re
big, long legged, short-tailed, saber-toothed, and long-snouted for scenting
prey. The smallest one is Aelurognthaus,
slightly bigger than Lophorhinus with a bigger head and huge fangs. Arctops was
slightly bigger in turn, with a low, foot-long skull. Still bigger was
Gorgonops, which had six species with different shaped and sized skulls. Some
were smaller than Arctops, others much bigger, the size of a Great Dane. Bigger
still is Dinogorgon, with a heavy, robust skull. Finally, the biggest is the
10-foot Rubidgea, with a 1.5 foot skull and
8 inch fangs. The gorgonopsids
had smaller heads and lighter bodies than the dinocephalians, but their saber
teeth, razor incisors, and long limbs made them even more dangerous.
#8
The Permian
extinction brought these guys down, though. They were replaced by all sorts of
archosaurs-scaly, fully erect, fast moving animals that lacked the saber teeth
but had batteries of broad, curved flesh-rending slicers. This particularly
dangerous one is Silesia, in the Norian, about 210 million years ago. The
Triassic period has allowed for the archosaurs to diversify into all sorts of
forms and by the end of the period, as we’ll see, there’s quite a few kinds of
predators. You should remember these from my Teratosaurus writeup.
I guess I’ll start with the
nastiest. This is a twenty foot predator with two foot skull filled with
four-inch curved serrated teeth, named Smok after the legendary dragon of
Warsaw. It had a long body and long tail with long front and very long back
feet, long enough for it to be reconstructed in a bipedal post. It has yet to
be completely described, so it’s uncertain whether it’s a rauisuchid, dinosaur,
ornithosuchid, or basal archosaur is. What definitely are rauisuchids, big
armored erect animals that look like a cross between a crocodile and a
predatory dinosaur, are Polonosuchus and Teratosaurus. These animals are only
subtly different, and probably inhabited different regions of Europe.
Smaller is the first large
predatory dinosaur, Liliensternus. This German theropod weighs 400 lbs compared
to the rauisuchids 700 lbs, but is much faster, with a long flexible neck and
two long hind legs perfect for running. They eat smaller prey, but that would
still include animals the size of humans. In a similar position is the slightly
smaller non-dinosaur cousin Ornithosuchus, from Scotland. This animal is more
basal, much more like a crocodilian, but still capable of bipedal running in
times of need. It’s shorter than Liliensternus, but more heavily built and with
a larger head on a short neck, so it would be an ambush predator of smaller
prey.
In the water, there are
phytosaurs-distant relatives to crocodiles that occupy the same ecological
niche. In Europe, the species Termatosaurus, Rileyasucuchus, Rutiodon,
Paleorhinus and Mystriosuchus swim the rivers, hunting mostly fish and
amphibians, but also preying on whatever ventures too close to their freshwater
streams. They share this niche with giant amphibians, similar to Eryops with
weaker limbs, much longer bodies and tails, and slightly narrower skulls. Like
the phytosaurs, they play the crocodile role as predators of the shallows,
lying in the mud until prey wanders too close. The two in Europe are frog faced
Metoposaurus and the more gator-shaped Cyclotosaurus, and they are not picky
eaters-if prey goes close enough, it’s gone in a quick powerful snap.
#7
Now we’re in more familiar times, the time of dinosaurs.
One of the richest fauna is the Morrison formation, in today’s Utah and
Colorado. Dinosaurs by this point diversified into big spiky stegosaurs,
ornithopods like Dryosaurus and Camptosaurus, and a whole plethora of huge
sauropods. With all this meat, the predators are likewise big and menacing. The environment consists of long rivers and
wide floodplains, interspersed with huge, dense forests. First things first,
let’s deal with some waterway predators. The amphibians and phytosaurs were
wiped out by the Triassic extinction, and now they’re replaced by
crocodiles. These crocodiles belong to
the genera Eutretauranosuchus and Goniopolis, and they’re roughly the same
physically as modern crocodiles and live the same way.
The land predators are all theropod dinosaurs. The
smallest is a Megalosaur, Marshosaurus. Marshosaurus is about 15 feet
long, the size of the rauisuchids and
early theropods of the Triassic, but far more advanced. The skull’s about two
feet long, and filled with the curved serrated teeth that make the hallmark of
the predatory theropods. Big enough to eat a human, but it’s a pygmy compared
to the other Morrison theropods and is very obscure and rare.
Bigger still
is Ceratosaurus, from its own group of theropods, the Ceratosauria. Ceratosaurus
is distinct for the small four-fingered hands, a long bony ridge on its back,
hornlets over the eyes, and a large flat horn on the nose. The horn is long and
deep, for social display. Ceratosaurus ranges from the size of Marshosaurus to
about twice the size at about a short ton in weight and 25 feet in length. It is rarer than the bigger Allosaurus (more
on him later), and has a distinct dentition of huge teeth in front of the
maxilla and shorter ones elsewhere.
Paleontologist Robert Bakker, in an essay in the book Feathered Dragons: Studies on the Transition
from Dinosaurs to Birds, speculates that Ceratosaurus might have been a
wetlands specialist, using its muscular tail to swim in the shallows hunting
fish, turtles and crocodiles but not above scavenging or attacking dinosaurs.
The most common predator in the Morrison is the famous Allosaurus. Allosaurus ranges from 25-40 feet long, big enough to easily overpower the ornithopods, menace the well –armed Stegosaurs, or even take on a sauropod. This dinosaur has powerful arms tipped with large curved talons, rows and rows of serrated, curved teeth and a deep head and a wide jaw gape. This suggests that it used not bone-crushing bites or claw slashes to dispatch prey, but instead struck using its open mouth as a weapon. The teeth would create long, deep bloody wounds, and the prey would go into shock from blood loss. This is ideal for taking down giant sauropods-too big to overpower, so bleedout would be the best chance to take them down.
Even bigger than the Allosaurus is Torvosaurus, a
megalosaur similar to Marshosaurus. Torvosaurus is very likely a descendant of
Megalosaurus, and a rival to Allosaurus. Two species live in the Morrison
Formation, and like Ceratosaurus, both are rare and associated with riverine
parts of the ecosystem. It would probably avoid going too far inland or risk
confrontation with the other predators., but would easily be Allosaurus’ match
in a confrontation, or be able to take down a small sauropod. Torvosaurs, Allosaurs, and Ceratosaurus also
lived in Portugal’s Lourinha Formation as well, in a similar environment and
eating the same kind of prey.
The largest of the Morrison predators is no doubt a
sauropod hunter, and the first in a long line of giant carnosaurs specializing
in bringing down huge prey. This is Saurophaganax, sometimes considered a species of Allosaurus, and a truly formidable
predator. It is even larger than Allosaurus and Torvosaurs, at about 40 feet or
more, the size of a Tyrannosaurus rex. This animal is the state fossil of
Oklahoma, but much rarer than Allosaurus fragilis. Perhaps Allosaurus is more
versatile a predator, or perhaps it compensates for smaller size with social
behavior. Nonetheless, it is the top predator, the largest in the world for
millions of years, and the first of a long, terrifying legacy of giant
allosaurs.
#6
This next fauna, however, has only the giant allosaur. The megalosaurs
and ceratosaurus are extinct in North America, and the allosaurs with follow
them, but there is one last monster. This is Acrocanthosaurus. At 40 feet and 7
tons, it would not be surpassed by other theropods on the continent until
Tyrannosaurus itself. Instead of lacrimal crests like Allosaurus, it has a
2-foot sail along the neck, back, and tail. Like Allosaurus, it’s armed with
large claws and teeth and also specializes in hunting sauropods. There have
been tracks found showing Acrocanthosaurus chasing down sauropods. Sauropods would be the ideal prey, as Acrocanthosaurus
is bigger than any of the iguanodonts, even the huge Iguanocolossus, and
Gastonia was an armored dinosaur covered with nasty spikes.
Iguanodonts like Hippodraco, Eolambia, and especially Tenontosaurus
would be prey for the next largest predator. At the Morrison formation, the
only maniraptoran dinosaur was the tiny Palaeopteryx. However, by this time,
they’ve spread, diversified, and grown to formidable size. The largest of these
dromeosaurs is Utahraptor. Remember the “Velociraptors” from Jurassic Park?
Remember that big one that seemed to be in charge? She was roughly the size of
a smaller Utahraptor. Utahraptor are the
size of bears, armed with the usual teeth, claws, and a huge curved talon on
each foot. To make matters worse, dromeosaur footprints have been found in
groups, suggesting that they are social hunters as well. The large claws on the hands and feet could
be used to slashing or stabbing blood vessels, grappling to subdue, or just
hanging on while tearing at the prey with its teeth. A human would be simple
prey.
Human-sized prey would be vulnerable to Deinonychus, roughly half the
size of Utahraptor. A group of subadult Deinonychus has been found with the
body of a Tenontosaurus-scavenging turned feeding frenzy? Teenage gangsters
biting off more than they can chew? Attempt at scavenging from adults or bigger
predators gone horribly wrong? If they were pack hunters, they could take on
larger prey. Deinonychus is faster and more agile than Utahraptor, but still an
ambush predator, too slow to outpace most of its small prey.
About the same size is Nedcolbertia, a long but slimmer coelurosaur
that must be a specialist in small prey, but a faster runner than the
dromeosaurs. There’s also Geminiraptor,
a slightly smaller relative of Deinonychus. Finally there’s the troodont
Yugovectia. Troodonts are smaller and more gracile than dromeosaurs, but faster
and smarter. They must have the best claw-eye coordination, and probably eat
small, fast prey but their sickle toe claws also suggest hunting larger prey.
#5
Our next fauna is across the Atlantic and a few million years later. No
dromeosaurs here, but some old tribes in new forms. This is the wet delta of
North Africa, stretching from Morocco and Niger to Egypt. The environment, and the fauna, is not too
different from the Morrison. No stegosaurs, but they’ve been replaced by
iguanodonts. While the sauropods are not as diverse as before, they’re just as
abundant and huge. The armored sauropod Paralititan weighs over 60 tons. Even
the fish are big-the coelacanth Mawsonia, sawfish Onychopristis, the bichir
Bawitus, and lungfish Neoceratodus all reach sizes of almost 20 feet.
The smallest predator is a ceratosaur, and fulfills a similar role as
its ancestor. Rugops has a lightly built skull with a short snout, wide curved
teeth, and a number of crests and rugosities on its face for display. The small
size, light skull, stubby claws, and short teeth make it less of a sauropod
hunter and more of fisher, scavenger, and chaser of baby dinosaurs. The
environment’s wetness provides plenty of crocodiles, fish, frogs, and carcasses
for Rugops.
Rugops would have to give way to one crocodile rival, however. Kaprosuchus,
the boar crocodile is the same size as Rugops, but more than a match. Armed
with a horned 2-foot skull and an array of teeth growing up to 5 inches, it can
a meal out of any ornithopod or small sauropod that wanders to close to its
place of ambush. The eyes in most crocodiles are laterally situated so they
have a wide field of vision, but Kaprosuchus has eyes oriented forward like a
dinosaur for judging depth. Unlike the conical teeth of its relatives, its
teeth are flattened to form sharp edges and long enough to pierce deep into the
flesh of dinosaurs. This animal lurks by waterholes, ambushes prey, and with a
rush, tears them apart with its powerful jaws.
The next bigger theropod was also a ceratosaur. Deltadromeus’s skull is
as of now unknown, but the arms and legs are long and powerful, and the animal
is about 25-30 feet in length. That suggests that it hunts the faster iguanodonts
rather than sauropods, and so doesn’t compete with either the fish-eaters or
the giant predators. Unfortunately, teeth or skull material associated with the
known remains are yet to be found, so the specializations are yet to be
entirely established.
Another mysterious predator which may be the same as Deltradroemus is
Bahariosaurus. So far, only the ribs and vertebrae have been found. To make
matters worse, the material was destroyed by Allied bombers in the total war of
mutual extermination called World War 2. The material suggests a huge but
gracile animal, possibly a ceratosaur or carnosaur the size of Tyrannosaurus
itself. No teeth or claws have been found, so only the vertebral form and pubis
suggest that it’s a theropod in the first place. I would bet on it being a big
ceratosaur myself, but it’s one of those mysterious dinosaurs. Perhaps someday
we’ll find the rest.
Fortunately, we do have existing material for the next three giants of
the fauna. This next one is a relative of Allosaurus but only known from the
top of the skull. ThThe piece is high and thick, but recognizably allosaurian.
Allosaurs all had tall ridges on top of their eyes, but this one is
particularly thick. This feature on the eye led to the brilliant name
Saurinops, after the restless eye of Tolkien’s Sauron. Like other allosaurs, it
would be a specialist in ripping open sauropods with its teeth. The
aforementioned adaptation is evolved probably for head-butting, suggesting a
kind of social structure. These features, along with trackways of carnosaurs
moving in groups, leads to a terrifying conclusion: they hunted in groups.
What did the rest of Saurinops look like? Fortunately, we have a
relative from the same formation. Like Bahairiosaurus, it was discovered by
Ernst Stromer in the 1930s and the holotype lost in the war. Unlike Bahariasaurus, additional material has
been found, and now we have a very good idea of it. Carcharodontosaurus weighs
in at almost 10 tons, more than 40 feet, and with a 5-foot head. Everything I
said about Saurophaganax is true here, except that Carcharodontosaurus has much
smaller, weaker forelimbs. Like its allosaur predecessors, Carcharodontosaurus
has a large head armed with broad, serrated teeth for inflicting bloody wounds
on giant sauropods. This dinosaur is a giant-killer.
The biggest theropod here, in fact the largest of all time, is a
bizarre one. You see, since the rise of the allosaurs, the megalosaurs
declined, and from their stock came a new group of giant predators-the
Spinosaurs. These animals have long limbs and huge claws, long narrow snouts,
tall vertebral spines, and long conical teeth. They’re also huge.
Spinosaurus is the most spectacular-more than 12 tons and more than 50
feet, bigger than any other theropod. Like Bahariasaurus and
Carcharodontosaurus, its holotype was destroyed in the same bombing, and only recently has been known well. Now, the
freakish size is odd enough, and if it looked like the carnosaurian
reconstruction used for years, it would be even stranger for the 6-foot tall
fin on its back. However, recent discoveries have shown the head is just as
strange- almost 6-feet long, narrow, and armed with smooth, sharp, and conical
teeth. If you looked at the skull, you would immediately think of a crocodile.
Indeed, the connection based on morphology has been supported recently by an
isotope study showing a similar diet to crocodiles. Remember the giant fish I
told you about? Spinosaurus would be ideal for their predation. In addition, it
could easily overpower the small ornithopods, or scare off all but the largest
and most determined rivals from kill sites with sheer size coupled with the
size-magnifying fin. It probably would
never be able to bring down a sauropod, but it didn’t have to-just let a
carcharodontosaur or abeliosaur do it for it and then chase them off. The other, smaller theropods seem to be
specialists, but Spinosaurus’ unspecialized teeth and huge size suggest a jack
of all trade, preferring aquatic fare but easily subsisting on smaller
dinosaurs.
#4
Spinosaurs never made it to Asia and North America, though. Our next
fauna shows the triumph of the coelurosaurs. This is Mongolia, 77 million years
ago. The Bayan Shireh, Iren Dabasu, and Djadochta Formations show streams and
lakes only miles away from barren desert, much like Egypt or Texas today. No sauropods-ornithopods like Bactrosaurus,
therizinosaurs like Erlikosaurus and Segnosaurus, and ankylosaurs like
Pinacosaurus and Talauurus were the main herbivores, with amphibians, lizards,
birds and mammals providing a rich small-animal fauna.
The largest predator here is a theropod, but not a strict carnivore.
You see, one of the many coelurosaur lines of the Cretaceous are the beaked
oviraptors, perfectly capable of shearing through flesh or plant material with
their powerful jaws. This is the largest oviraptor-Gigantoraptor. 2 tons of
feathered fury, with a two-foot beak and foot-long hand claws, this is the
grizzly bear of Cretaceous Mongolia. It can easily overpower most of the
smaller animals of the day, and the beak would equally be suited for breaking
the back of a Protoceratops, tearing into the corpse of a hadrosaur, or
stripping a tree to the bare wood.
Nearly as big is a Tyrannosaur, a smaller version of the late
Cretaceous titan. Alectrosaurus was smaller and more primitive than
Tyrannosaurus, but still a fast-running, powerful-jawed predator. All that has
been discovered is a leg, foot, and some body elements, but not the skull.
Still if it’s anything like the other Tyrannosaurs, it’s a truly formidable
predator.
The Dromeosaurs are still here. Remember Utahraptor? A slightly smaller
relative, Achillobator, is here, big enough to bring down most of the prey
dinosaurs in the area. Three dog-sized relatives share the fauna-the infamous
Velociraptor and its sister taxa Tsaagan and Linheraptor. If they were social
predators, they could take down larger prey. They certainly consider
Protoceratops a food item-the ceratopsian has been found in a fossilized death
struggle, fighting to the death with a hungry Velociraptor. Gigantoraptor, too, has smaller relatives
here. While Citipati is not nearly as big as Gigantoraptor, it’s almost the
size of a human being and no doubt a formidable animal. Finally, there’s Troodonts-they’ve
been successful little predators. The largest one here is the nasty
Saurornithoides.
#3
While the next 60 million years have had their share of predators, from
Tyrannosaurs to Hyeanodonts to big predatory birds to terrestrial crocodiles to
giant omnivorous pseudo-pigs. However, carnivore diversity finally reached its
apex in the Miocene epoch. Where we’re
looking at is France in the Asteracian age, about 16 million years ago. The
huge array of bovids, horses, apes, rodents, and pigs led to a similar
flourishing of predator diversity.
Cats have finally evolved. There are two species here-the lynx-sized
Pseudaelurus loreti and the puma-sized Pseudaelurus quadritentatus. By now,
cats have evolved their winning characteristics: powerful muscles, short jaws,
long canines, amazing eyes and ears, long whiskers for hunting by touch, and
fast reflexes for ambushes. P. quadritentatus probably hunts the local apes the
same way leopards do…including humans.
There’s also false cats, the nimravids. There is only one now, the
leopard-sized Prosansanosmilus, but it will soon be followed by the bigger,
burlier Sansanosmilus and almost bearlike Barbourofelis. They’re almost
identical to big sabertooth cats, but they have much lower, longer bodies and
shorter legs.
There’s a very old group here. The creodonts, distant relatives of
Canivorans, used to be the main predator for 20 million years. This is the last
of them- Hyainailuros. Like all Hyaenodonts, it has a long body, short legs, and
a huge head armed with large bone-crushing teeth. It’s also one of the largest,
the size of a grizzly bear. Only in Africa and Western Europe has the once
great order survived, being succeeded by false cats, true cats, bears, dogs,
and bear dogs.
Bear dogs are the top predators of the day, combining doglike predation
with bearlike strength and size. They range from the dog-sized Pseudarctus and
Cynelos to the massive Amphicyon and Pseudocyon, both reaching the size of a
brown bear or a Siberian tiger. In between are Euramphicyon and Agnotherium.
These six genera dominate the middle Miocene as apex predators, being bigger
and more formidable than any other predator. Ambush predators, they can quickly
run down and overpower prey with lionlike forelimbs and huge powerful jaws.
They do have rivals, though; the late Miocene is one of the most
diverse periods in mammalian prehistory, both in prey and in predators. The big
hyenas have made their debut with Percrocuta, larger than a spotted hyena today
and just as deadly a predator. There are
also some primitive bears, Hemicyon and Plithocyon-they resemble their
amphicyonid neighbors, but are bears that are still doglike in form and more
carnivorous than modern bears. They would share the same roles as the cats,
false cats, and bear dogs. At the size of black bears, they’re powerful
predators but still overshadowed by Amphicyon and Hyenailuros.
#2
Fast forward 8 years and go back to North America.
It’s the Hemphillian age, and it’s a period of faunal turnover. Species are
going extinct, some are arising and some are arriving from Asia. The natives include bear dogs and true dogs,
but bears and sabertooth cats are coming to displace them.
The biggest, baddest predator of the age is
Agriotherium. Agriotherium is a bear, but a super bear as well. Big an as
Alaskan grizzly, its skull has evolved to withstand incredible stress,
especially around the carnassials and canines. This suggests that unlike modern
bears, it eats more meat than vegetables. Agriotherium has been found on every
continent but Australia and South America, dispossessing the bear-dogs and
finishing off the hyeanodonts. The species will only die out with the onset of
the ice ages.
There is another intruder, Machairodus. This is the first of the sabertooths,
and the first big true cat. The sabers are shorter and studier than later
saberteeth, but still powerful enough to pierce flesh and sever arteries. Machairodus is as big as a tiger, and like
Agriotherium has conquered most of the world and will last until the ice age.
These two predators have cut down the bear dogs and nimravids, and forced the
dogs and hyenas to secondary roles.
There is still some of the old guard left, however.
Barbourofelis is the last and largest of the Nimravids; as long as a leopard
but built like a bear and bearing huge saber canines. This predator has been
fine bringing down tapirs, horses, and rhinos for the past 5 million years, but
its time have come to an end with the invasion of Machairodus.
Likewise, the bear dogs are displaced. The last
American bear dog is Ischyrocyon, the size of Machairodus but lacked the
powerful sabers. Ischyrocyon has always kept Barbourofelis in its shadow, but
against these two new predators, it’s obsolete and will not survive for much longer.
The dogs are not beaten yet, however. About 16
million years before the present, dogs became big predators, placing pressure
on the nimravids and bear dogs and even overmatching them with their social
hunting. They adapted to hunting large prey by developing bone-crushing jaws,
making them very much the hyenas of America.
The oldest and most successful genus, Aelurodon, is down to its last
species, and it’s almost extinct. The largest, in fact the largest dog that
ever lived, is Epicyon Haydeni. This dog
is the size of a St. Bernard or Newfoundland, and armed with massive jaws and
bone-shattering teeth. In packs they are unstoppable. Only Machairodus and
Agriotherium now bring its downfall.
There’s a smaller species of Epicyon, E. saevus, and
this species is always found alongside its giant cousin. Right now, it’s doing
poorly, being replaced by the new species of bone crushing dog, Osteoborus.
Epicyon will linger on, but it will perish along with Barbourofelis as
Machairodus takes over. The dogs are
falling, but not out. The coyote sized Canis lepophagus is the first of its
kind, but it will grow and rise and conquer. By the end of the ice age, Canis
will have reached every continent., and when it is paired with a new social
predator of African descent, it will rule the world.
#1
Now, originally I was going to do Pleistocene Australia,
but then I realized I already covered that. Here’s the link-http://davidsamateurpalaeo.blogspot.com/2013/10/heres-something-i-made-before-i-started.html
So instead I’m going to Los Angeles around 100,000
BC. While humans are inventing culture and technology across the Old World, the
Americas are full of powerful predators.
Cats by now have spread and diversified to an
extreme extent. By now, America has lynx and bobcats and all sorts of big cats.
Pumas have already evolved, and by now they’ve covered both North and South
Americas and become a very successful midsize predator. Jaguars have likewise spread, ranging from Philadelphia
to Seattle to Buenos Aires. Both of these are present at La Brea, but they were
shadowed by the bigger, stranger cats.
Miracinonyx is a close puma
relative evolved to become a cheetah. While being the size of a puma, the
spine, tail, skull and limbs have all evolved to a cheetahlike lifestyle.
Pronghorns today are by far the fastest mammal outside of Africa, begging the
question why considering how easily they can outpace even wolves and cougars.
This is why-antelope-eating cheetahs require the antelope to speed up in turn.
There’s also a relative of the lion here, Panthera
atrox. Lions and tigers have spread from Africa to every continent but
Australia and Antarctica, competing and eventually succeeding the sabertooths.
This particular species ranges from Alaska to Peru. Up to 800 lbs, they are
much bigger than their African relatives. The lion is more common than jaguars and
pumas, but less common than the sabertooth at the Tar Pits, and lives in small
groups of 4 to 2, much smaller than African lion prides. The brain is larger than the sabertooths,
suggesting it was smarter. It’s also
more of a cold weather cat as well.
Another cold-weather cat that is also rare in the
Tar Pits is Homotherium, the scimitar tooth cat. Homotherium weighs as much as
a lion, but a meter at the shoulder and less than two meters long. The front
legs are long and high, while the back legs are much shorter but very powerful.
They share every habitat that lions do, but target very different prey. Lions
hunt horses, deer, antelope and bovids. Scimitarteeth , however , specialize in
picking off elephant and rhino babies. They will take whatever they can find,
but they prefer to run in small gangs to surround herds of mammoths and
mastodon, and quickly strike down and kill vulnerable infants.
Of course, the biggest sabertooth and by far the
most common feline at the pits is Smilodon. This is a North American species,
ranging from Oklahoma to Peru, smaller than its southern relative. The northern
sabertooth is shorter and smaller than the lions, but incredibly heavily built
and reaching 600 lbs. They take horses and camels as prey, but also big
dangerous animals like sloths and bison. Isotopes show a preference for camels
and bison. Hunting in packs, they surround and ambush prey. They don’t run as
fast as scimitars or cheetahs, but gang up on the herds, overpower them with
their incredibly muscular and heavy forelimbs and claws, and then cut their
prey’s throat with a bite. The fact that
the sabers are so long shows the size of their targets.
Cats aren’t alone. There are dogs-red fox, coyote
and wolves live the same way they do during the human occupation of the
continent. There is one particular species of wolf, however, that is unique to
the time and to the American continent.
Dire wolves are big-the size Canadian and Russian wolves today or
larger. The brain is smaller than the grey wolf, but the skull is sturdier and
legs are shorter. The teeth are big, and carnassials have long blades. While
the grey wolves hunt deer and smaller prey, dire wolves hunt bison, camels,
horses, and other megafauna. The skull is adapted for crushing bone, and they
compete with sabertooth cats the same way Hyenas do with lions in Africa. Big bad wolf, indeed.
Finally, there are bears. Now, this area is
relatively flat, so black and brown bears are uncommon. Instead, the bear of
the plains is Arctodus simus, the northern short-faced bear. This bear is the
size of an Alaskan brown bear, but with a shorter snout and longer front
legs. Ranging from Alaska to Texas, this
bear ate more meat than vegetation, unlike its extant spectacled bear cousin. There are three opposing theories in paleontology
on how it gets its meat. One postulates that its gracile build makes it a fast
runner to chase down horses and deer. The second argues that it’s too heavy to
run and instead overpowers slower sloths and bison with brute strength.
Finally, there’s a party that argues that it’s too slow to run and too weak to
fight, and so is a scavenger that uses sheer size to intimidate other
predators. I’m of the opinion that it does all three to some extent. It can’t
outfight a mastodon or outrun a pronghorn, but it can bring down most animals
in between. And, like all carnivores, would never hesitate to take a carcass,
and a long-distance giant (remember Spinosaurus?) could quickly find and take
whatever dead meat is available. With
its size and strength, it can win a fight against most adversaries, even
sabertooth cats.
No comments:
Post a Comment