1. Placental Carnivores: Past and Present
Ilse Kotzee
Student #
Landscape Ecology and People
University of the Western Cape

2. Placental Carnivore Definition:
Placental refers to a mammal who gives birth to live young, which is nourished throughout the pregnancy by placenta; a specialized organ attached to the uterus wall. (
Carnivore refers to any animal whose diet consists mainly out of meat. ( )
Presently there are about 260 placental carnivores (

3. Creodonts and Carnivores
Placental carnivores represented by two orders:
The now extinct Creodonts
The very successful true Carnivores
By the start of the Paleocene to Eocene two major groups had made the transition from insect eating insectivores to specialized meat eating carnivores. The two groups of mammals known as Creodonta followed closely by Carnivora, is believed to have evolved to fill the ecological niche left open after reptiles became extinct in the Cretaceous period allowing herbivore numbers to increase exponentially. Due to the rapid evolution and specialization of the carnivores, no other group was able to compete with the existing Creodonts and later true Carnivores.

4. Creodonts Primitive carnivorous mammals
Long and low scull with primitive brain
Head large in proportion to body
Short and heavy limbs; long tail; sharp clawed toes
Hyeanodon gigas

5. Carnivores Dominated from late Eocene up to present day
Large brain case
Good sense of smell
Well developed canines
Shearing and crushing teeth
Strong body capable of powerful movement
Lion

6. Adaptations
Differ from insectivores in having special pairs of upper and lower carnassials
Dagger like canines used for stabbing, main weapon for killing prey
Strong incisor teeth used for nipping
Carnassials are specialized cheek teeth which are able to cut meat like a scissors, makes swallowing easier and facilitates quick assimilation in digestive system

7. Carnivore evolutionary timeline
The more primitive of the two groups the Creodonts enjoyed dominance in the early Paleocene to Eocene which is MYA ( Very early in their evolutionary history the creodonts branched off into the Oxyeanides and the Hyaenodontids. The Miacids which are believed to be the earliest true carnivores enjoyed dominance in the Paleocene and in the Eocene before evolving into the carnivores which exists today. Carnivora is a large order and is divided into two suborders; The Fessipedia and the Pinnipedia The Fessipedia (also known as terrestrial carnivores) includes Canoidea (wolf, bears raccoons and the weasel families and Feloidea (cat like carnivores) represented by cats, civet and hyena families. The Pinnipedia your marine or fin footed carnivores which includes seal, sea lion and walrus families.

8. The Oxyaenids Characteristic long body, short limbs and very long tail
Can be compared to martens and cats of today
Diet consisted out of birds, eggs, small mammals and most likely still insects
Capable of climbing trees
Occurred in late Paleocene in North America. First definitive creodonts.
Reconstruction of the cat-like creodont Oxyaena

9. The Hyaenodontids Resembled hyena's and dogs of present time
Reached very large sizes
Had longer limbs, so were better runners
Active predators, able to compete with true carnivores for short time
Much more abundant than Oxyaenids
The Oxyaenids differed from the Hyaenodontids in that they had carnassials situated in the first upper molar and second lower molar, whereas the Hyaenodontids had theirs in the second upper and third lower molars. ( Largest Hyanodontid Megistotherium lived 20 million years ago in the Sahara and weighed 800 kilograms. (

10. Extinction of Creodonts
A change in temperature may have favored the early carnivores
No match for the true carnivores with greater intelligence and more specializations
During the end of the Eocene period temperatures gradually decreased by 12 degrees centigrade replacing evergreen tropical rainforest by deciduous trees. ( The creodonts were not highly specialized for the catching of prey, and had rather archaic adaptations, which meant with the appearance of the carnivores they were steadily replaced.(

11. Miacids Seen as most primitive representative of True Carnivores
Still had primitive features such as; a low scull, elongated body and tail, and short limbs, but larger brain
Diet consisted of small animals living in dense undergrowth or in trees
Resembled modern day weasels
Differed from the creodonts in that it had a larger brain which put them to a great advantage when it came to hunting. Seen as the most primitive representative of carnivores, because unlike the earlier creodonts their carnassials where much more toward the front and consisted out of the fourth upper premolars and first lower molars.

12. The Fessipeds Dominated from late Eocene till present time
They are the familiar and well known dogs, cats, raccoons, bears, wolves etc.
Order divided into two groups; Cannoids and Feloids
Division based on anatomical differences
Members of this order has molars along with carnassials which allows them to have a more varied diet.

13. Super family: Canoidea
The early Cannoids kept much of their primitive characteristics
Did show some elongation of limbs and feet
Carnassials more specialized for shearing then in Miacids
The brain case was also bigger
In the time period between the late Eocene and Oloigocene they showed no change or loss in the functioning of dentition, so still fairly primitive. Elongation of limbs showed the starting of evolution towards faster running, and sharper carnassials and a larger brain increasing their predatory abilities.

14. Canidae Has long legs, of all carnivores most adapted for running
They are social hunters that rely on speed to chase and pin down prey
Possesses an elongated muzzle and bushy tail
The muzzle has a convoluted spiral bone which enables it to run for longer distances and helps to conserve moisture and cools or warm the air before it reaches the lungs. (
Has a long nose with an acute sense of smell to track down prey and scent posts left behind by other animals.

15. Ursids
In the Miocene dogs started evolving into larger heavier carnivores
This could be where the ancestry of bears can be traced
Like dogs bears are very adaptable and widely distributed
Dentition more suitable for omnivory
The increase in size can be as a result of the decrease in temperature during the winter season.
The change in diet to include a large proportion of plant matter led to the carnassials becoming less developed and the molars flat and broad to accommodate crunching and grinding which makes the mastication of plant matter easier. With this the need to catch prey declined and as a result their limbs became more reduced, and their tails more stubby. By the Pleistocene the Ursids enjoyed their peak numbers. Bears can be found across South America strangely enough they are not found in Africa.
Panda

16. Procyonids The Oligocene gave rise to yet another Cannoid
A small, climbing carnivore with hand like forepaws, and flexible limbs
Differs from dogs in that they walk on the soles of their feet
Like dogs they have 5 toes ending in non retractable claws
With the Ursid family already starting the evolutionary trend away from the chase and kill, the Procyonids along with having a more omnivorous diet also became more adapted at climbing. Unlike the Ursids all the members of this family remained relatively small. They are represented by raccoons, ringtail, coatis, kinkajous,oningos and the lesser pandas. All of them are forest living, and spends majority of their time in trees or along river banks.
Kinkajou

17. Mustelids
Of all carnivores this group shows the widest range of adaptive radiation
Group consists out of primitive mustelines, the mellivorines, melines, mephitines and the lutrines
Can be identified by their tapering body and short legs
Each group’s diet and behavior is equally diverse
The primitive mustelines includes the weasels, the martens, the minks and their relatives as well as the wolverines. Mellivorines represented by the ratel or honey badger. The melines are represented by the badgers. The fourth group the mephitines are represented by skunks. The lutrines are the aquatic mustelids represented by the Lutra and the Otters. Diet ranges from small animals, insects, worms, berries, plants ,carrion and garbage.
Skunk

18. Viverridae
Included in the Feloid carnivores , is one of the oldest carnivores still living today; the civets
They first made their appearance in the Eocene and lower Oligocene age
The small, forest living genet ‘s ancestry can be closely linked with that of the civet’s
The Civets are in many ways like the Miacids only with a few modifications. ( Seen as the ancestors for the Feliods because they lost their last molars paving the way towards true carnivory.
Genet

19. Herpestidae
Recently split from the civet stock due to technical details in anatomy
Least known and studied of all carnivores
Small carnivore, with short legs and a long tail
The structure of the auditory bulla and anal sacs differs from that of the Civets and therefore the Herpestidae forms a group of its own. (
Mongoose

20. Hyaenidae Very large and heavy descendant of the civet
Hyena has heavy skull, with strong enlarged teeth for cracking bones
Legs are elongated for faster running.
Highly specialized carnassials with almost no molars
Included in this group is the hyena and aardwolf. Members of this group’s fore limbs are longer then the hind limbs. The Aardwolf has a lighter built and skull is not as heavy, the dentition is also more reduced with very simple conical cheek teeth.(
Hyena

21. Nimravidae
The evolution of cats mirrors that of the Hyena only occurring earlier
A very successful group that very rapidly evolved into the modern day cats we know today
The Nimravids showed many of the features copied by modern day felids. ( This means that the felids did not undergo many physiological changes and kept true to their original form. The Nimravids were the first to sport saber toothed carnivores.

22. Felidae: Cats
Includes the lynxes, lions, leopards, jaguarundi, tigers, bobcats, mountain lions, ocelots and cheetahs
Members of this group are the ultimate carnivores
A distinguishing feature is their four toes ending in retractable claws
Top class hunters, with acute sense of smell, hearing and excellent balance
Although the felids can be traced from the Miocene they did not start deviating until the late Miocene. ( Unlike the Canoids who has molars along with the carnassials, the Feliod cats has only carnassials and their diet consist completely out of meat. Without the option of eating vegetable matter the Feliods had to adapt to sustain themselves with the sometimes very unreliable meat source. As a result Felliods are excellent hunters with larger eyes then most mammals capable of binocular vision and depth perception. Hunting after sunset is not a deterrent as they have excellent night vision and their highly sensitive whiskers makes moving around at night a cinch. They are also of the few mammals with the ability to distinguish between different colors. Their excellent sense of balance ensures that they always land on their feet. (

23. Felidae: Cats contd.
Two groups separates the Felidae into the big cats (genus Panthera) and the small cats (genus Felids)
The ability to purr distinguishes these two groups
Unable to run for long distances they are excellent sprinters
Big cats includes true lions, tigers. Leopards and jaguars, the small cats are represented by the bobcats, ocelots, lynxes and mountain lions. The small cats has the ability to purr, whereas the big cats does not purr but roar. Catches their prey with stealth and are able to catch prey twice their size with their muscular physique sprinting capabilities. (

24. The Pennipeds Includes the sea lions, walruses and seals
First appeared during Oligocene to Miocene
Made the move from land to water
Four feet are transformed into paddles with webbing between toes
Large size, with thick blubber
It is believed that pinnipeds evolved from a arctoid “bear like” carnivore. ( They made the move from land to water to take advantage of the abundant food in the South Pacific Ocean and to avoid predators. Ubandance of food due to major global change in climate about thirty six million years ago that cause a relatively abrupt cooling of ocean waters and altering oceanic patters (Repenning 1980) (
Although the Pennipeds became more stream lined for swimming they are not fully aquatic and are still able to move on land or ice flows. They wil move onto land in order to bear their young, sunbathe and molt. ( ) Some adaptations for life in the water includes, nostrils that close under water, and eyes adapted to see in the darkness that envelopes the underwater.(

25. Ottaridae Represented by eared seals and sea lions
Males larger then females
Able to dive and remain submerged for extended periods of time
Fur has even black color
Dentition specialized for eating fish
Males can be up to four times larger then the female. Specialization of lungs, heart and circulatory system makes it possible for seals to dive to great depths. Molars specialized for gripping and grasping slippery fish. A very sociable and vocal group.
Seal

26. Odobenidae Represented by walrus
A strong carnivore with little to no hair and no external ears
Diet consists out of mollusks taken from sea bottom with lips and tusks
Sociable and with groups of 1000 and more also polygamous
In order to aid locomotion on land the flippers can be moved backwards and forwards. The walrus has a distinctive feature a tusk which aids in
A characteristic feature of the walrus is it’s tusks which it uses during feeding, to defend it self and as ice pics for climbing .( ) Diet also includes small marine animals and fish. Once found as far as south of Gulf of St Lawrence and Massachusetts coast, today it is only found on the edge of the arctic ice sheet.(

27. Phocidae Of all the aquatic carnivores this group is most abundant
Known to be monogamous as well as polygamous
Hind limbs specialized for swimming cannot be used on land
Mottled fur that is spotted or banded
Represented by the earless seals. The seals are not able to move their flippers, and remains in a forward position so it moves around on land by wobbling on their stomachs. This strange movement is known as gulluphing. (

28. Newly discovered carnivores
This order is very progressive, and even today new members are being discovered
The cat-fox is a potentially new carnivore
Discovered in Indonesia (Borneo)
“The mammal is slightly larger then a cat, with red fur, a long tail and hind legs longer then the front legs” (
As the name implies the proposed carnivore is a cross between a cat and a fox.

29. References:
Colbert E.H., Morales (M) (1991) Evolution of the Vertebrates, 4th Ed. New York Wiley-Liss (Chapter 25)

30. References: http://www.kidcyber.com.au/topics/seals.htm