What's a Creodont?
Evolution
is seldom linear and the blue-prints for life includes rough drafts, evolutionary dead ends, and parallel development.
The earliest meat-eaters were not carnivores as we know them today.
The creodonts started in the early Paleocene and went extinct during the Miocene. It is theorized that they had smaller
brains, couldn't run as fast, and were less successful in hunting as the nimravids and felines that succeeded them.
The most cat-like of the creodonts were the Oxyaenids.
Oxyaenids
- Creodont "Cats"
The first oxyaenids appear in North America during the late Paleocene.
Unlike true cats which walk on their toes, the Oxyaenids were plantigrade. They had short, broad skulls, deep jaws,
and teeth designed for crushing rather than shearing.
Often compared to martens or cats, the Oxyaenids tended to have long bodies and tails with short legs. They most likely
relied on their sight and hearing for hunting.
Oxyaenids were specialized carnivores feeding on birds, small mammals, eggs and insects, and their paw structure suggest
they were capable of climbing trees.
Although often
described as "cat-like" creodonts, not all Oxyaenids resembled cats all that closely. The species below ranged from
weasel-like to bear-like! In other words, these primitive meat-eating mammals weren't nearly as cat-like as the later
nimravids and machairodonts. We've included them here just so our readers can get an appreciation of these early feline
"first drafts."
Oxyaena
resembled a modern civet
Oxyaena
A
lithe predator hunted in the trees, its body slung low to the trunks. During the late Paleocene to the early Eocene,
the creodont Oxyaena was the top forest meat-eater.
Looking like a very large civet "cat", Oxyaena had a fairly long, flexible body with short legs and five toed paws.
Unlike true cats, Oxyaena walked on the entire bottom surface of its feet. Its skull was broad with a long muzzle and a massive
lower jaw. The jaws were made for crushing bone, an adaptation often found in scavenging mammals.
The estimated weight of the various Oxyaena species range from about 6-17 pounds. Its body was about 3
1/4 feet long, not counting its long tail.
Oxyaena wasn't a fast runner, but could have easily used the trees for hunting arboreal animals or nesting birds.
Perhaps, like a leopard, it could have dragged scavenged kills up to the safety of the boughs.
Most Oxyaena fossils have been found in Colorado, USA.
Malfelis
- "Bad Cat"
During the
middle Eocene (49 to 37 million years ago), the largest meat-eating mammal from what would become of the Wind River Formation
of Wyoming was Malfelis badwaterensis.
The skull
recovered from actually from a juvenile animal since it still had its milk teeth when it died. The premolars of Malfelis
didn't have the robust, bone-crushing structure of the other creodonts. Also, the skull was relatively long and
narrow. These characteristics suggest that Malfelis had been a pursuit predator.
The skull
was under a foot long (remember, it was a juvenile), but it still indicates that Malfelis was the largest predator
in that territory for that era.
Malfelis
badwaterensis was added to the ranks of North American creodonts in 2007. Further studies need to be done
- hopefully with more fossil remains - to determine more about the possible habits of this "bad cat" of Wyoming.
.
Patriofelis
vorax
Patriofelis
In North America during the Miocene, some 45 million years ago, the cat-like creodont Patriofelis
hunted in the conifer forests. About the size of a modern-day jaguar, Patriofelis had short legs, a long tail, and
broad paws. The paws suggest that the creodont may not have run fast, but could have been a good swimmer.
Modern jaguars often hunt in the rivers. At the very least, Patriofelis was probably an ambush hunter.
Game in Nevada and Oregon was plentiful. Small horses started to travel in herds, taking advantage of the receding
forests. Could
Patriofelis lay in wait near watering holes, picking off unwary prehistoric horses and other herbivores?
One theory about Patriofelis' habits suggest that it led a semi-aquatic life. A specimen found in the
Bridger Lake sediment had very well-worn teeth. Bridger Lake once swarmed with turtles. If so, the turtles
may have been a staple part of Patriofelis' diet! To support this theory, coprolites containing fragments of
turtle shells have been found in the Bridger Lake sediment. Patriofelis definitely had jaws robust enough to
dine on turtles.
Patriofelis' predecessor Oxyaena, was a good climber but it looks like Patriofelis preferred
the water to the trees. If Patriofelis continued in the water, it may have evolved into modern pinnipeds.
So, the "father of cats" may actually have been more like the "father of seals!"
The largest Patriofelis - Patriofelis ferox - was about the size of a small black bear, with a disproportionately
large skull. The skull is also broad and short and have some aspects similar to that of a sea lion's skull. However,
unlike a sea lion, Patriofelis had a small brain case inside its huge, thick skull. Patriofelis ulta was
about a third smaller. Both species had broad, plantigrade feet and long bodies and tails. Some of the sketches
of Patriofelis resemble an otter on steroids more than a feline.
In the USA, fossils of Patriofelis have been found in Oregon , Wyoming, and Nevada.
The bear-like Sarkastodon
Sarkastodon - The Giant
About 35 million years ago, a giant meat-eating mammal stalked through Central Asia. Built along the lines of a modern
bear - but larger - Sarkastodon hunted large animals during the Eocene. With its massive size, Sarkastodon
may have even hunted brontotheres. Fossils of these great beasts have been found in Mongolia.
Sarkastodon mongoliensis stood about 6 feet tall at the shoulder when on all fours.
It had a large, raccoon-like tail, but no one is sure if it was bushy like a raccoon's. Its powerful, stocky
body was about 10 feet long. While on its hind legs, it could have touched an object 19 feet off the ground with its front
claws. It would have weighed in about 1.5 tons, about as heavy as a small rhinoceros!
Why so large? Central Asia during the Eocene was home to huge mammals, such as rhinoceroses, brontotheres and chalicotheres.
Sarkastodon needed to be large to hunt such gigantic prey. The fossilized teeth of Sarkastodon
show that it ate a variety of foods and probably led a lifestyle similar to that of modern brown bears. Unfortunately
for Oxyaenids in general, their teeth were not as suited for as wide a variety of foods as later Carnivora.
A possible example of how true carnivores eventually replaced the huge creodonts like
Sarkastodon is the hypothetical competition between Sarkastodon and the slightly smaller carnivore
Agriotherium. The two bear-like predators were very similar in appearance and
habits. Both animals possessed crushing jaws, but Agriotherium may have outlasted its creodont competitor
due to its ability to eat plant material and small animals because of advanced teeth present in the Carnivora. Also,
unlike Sarkastodon, Agriotherium was digitigrade (walked on its toes) and could run faster. An encounter between
Agriotherium and Sarkastodon could have gone like this:
The immense Sarkastodon heard the sounds of flesh being rent long before he saw the cause. He followed the sounds,
aware of the hunger in his own belly. Ere long, he came upon an Agriotherium voraciously chowing down on a fallen Brontotheres.
The Agriotherium
regarded him briefly with one piggy eye, then buried its muzzle into its kill. The Sarkastodon sized up the situation.
The Agriotherium was just as big as he was but much faster. If he tried to fight it for the Brontothere, he would wind
up badly wounded or dead. All he could do was wait until the Agriotherium left and hope there was some meat left to
scavenge.
"I'm not sharing!"
growled the Agriotherium between wet mouthfuls.
"And Agriotheriums
are known for their generousity, too," mused the Sarkastodon calmly. "I'm not even hungry. I just want to stare
at you eating all day and take in your savage beauty."
The Agriotherium
stopped chewing and actually raised its head to stare at the Sarkastodon. It probably wouldn't leave, but it was definitely
rattled.
"Sarkastodons
are just weird," it snorted. "You're slow and stupid and my kind are going to bury you all."
"Well, thanks,
darlin'. It'll be such an honor being driven to extinction by a swell, intellectually advanced mammal like you," beamed
the Sarkastodon toothily. Although the bloody Brontothere smelled delicious, he managed not to drool.
In reply, the
Agriotherium tore out a huge piece of haunch and waddled off down the path, grumbling to itself. As soon as it retreated
out of sight, the Sarkastodon threw himself upon the tasty remnants of the Agriotherium's feast.
Whew! That
time the Sarkastodon's tactic worked, but sooner or later the Agriotherium (or maybe some smart primates) would figure it
out. Then the Sarkastodon would become extinct, but its legacy would live on...
Sarkastodon died out around 30 million years ago while Agriotherium persisted until as recently
as 1.5 million years ago.
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