All cats are predators whether domestic or wild, but despite being hunters most members of the family are shy and secretive. They prefer to keep away from human presence and are rarely seen. All cats have brilliant mix of remarkable stealth, astonishing agility and powerful but awfully supple muscles making them superb hunters. Man has always drawn awe and inspiration, envy and sometimes chilling fear from the above qualities of these extremely fine creatures. Except Australia and Antarctica wild cats are found on every continent, in almost every environment — world’s highest mountains like Himalayas, thickly forested swamps, lands bordering snowy Arctic, open wide plains, conifer jungles, savannahs, dense forests and even scorching deserts.
No evidence is available to prove when and how these graceful animals originated, but there is also no difference of opinion that they have been here for millions of years, however, the initial forms were very different from the present ones in physical characteristics. Fossil records of the ancestors of present-day wild cats come from a period of just about 10 million (1 crore) years ago. Despite the fact that there is no clear-cut clue to establish how and when these cats came into being, a study published in 2010 in Molecular Phylogenetics and Evolution has given insight into the precise evolutionary relationships of the big cats. According to the study tiger and Snow leopard are sister species, whereas the jaguar, leopard and lion are more directly related to each other. Snow leopard and tiger deviated from the ancestral big cats nearly 3.9 Ma (Megaannum, one million (1,000,000) years ago. Out of these tiger evolved into a distinctive species towards the end of the Pliocene age, around 3.2 Ma. Ancestors of leopard, jaguar and the lion diverged from other big cats from 4.3-3.8 Ma. Between 3.6 and 2.5 Ma jaguars moved away from the ancestors of leopard and lions, while lions and leopards separated from one another about 3.1-1.95 Ma.
Early big cats are divided into three basic categories on the basis of fossilized teeth found at different places. One group, which is represented by Nimravus, had long-limbed body built for speed and extra-long canine teeth and is known as the “false saber-tooth.” Second, “true” saber-tooth included tough beasts with really big upper canines. Third category is comprised of big cats with “normal” teeth with looks more or less that of the modern cats.
For quite a long time, experts believed that today’s cats evolved from the false saber-tooth, possibly even from something like Nimravus. While true saber-tooth, considered as a freakish evolutionary experiment by nature that failed. This hypothesis has been challenged quite recently. On the basis of remains other than teeth, some experts advocate that the true saber-tooth and the “normal” cats were directly related. They claim, the group characterized by Nimravus was an independent branch of the family tree that sprang very early and died away after a while. If we accept this theory then Nimravus has been inappropriately credited as a prototype of modern cats.
Whatever evidences are available they are insufficient to pinpoint the lineage through which felines have evolved. Cats are among the seven living families belonging to the order of mammals and are known as carnivores; others are dogs, bears, hyenas, aardwolves, raccoons and their relatives, weasels and their relatives and a group called viverrids, which include civets, mongoose and the odd fossa (cat-like, carnivorous mammal found in Madagascar). It resembled so much with a cat that biologists once classified it as one.
All Cats came from viverrids?
The animals that evolved into cats are thought to have come directly from viverrids, or from the creatures that were the relatives of both cat and civet clans. However, the cats evolved the qualities that characterize them were being put together in animals that lived at least 25 million (2.5 crore) years ago or possibly existed much earlier.
It is said that hints of what the early cats may have been like can be understood, with a little imagination, in a few types alive today. One of them is clouded leopard, which has more elongated skull like those of the earlier felines, in contrast to the rounded heads of most other modern cats. Furthermore, no other living cat has such large canines compared to the body size. They are almost as long in relation to the skull as the saber-tooth used to have. Another such example is Iriomote Cat whom some experts claim no more than an isolated but a close relative of small leopard cat. Others claim it is only one of its kinds, similar to the primitive ancestors of modern day cats. Reason is it seems to share some peculiarities, including external anal scent glands, with the viverrids. It is presumed, such glands may have been present in the early cats, or in their direct predecessors, and might have gradually vanished through evolutionary changes.
According to the believers of the cats’ primitive status it is similar in some respect to a fossil cat, Pseudaelurus. Though it was larger than the Iriomote cat, the two seem to have a similar structure of bones. Pseudaelurus, whose fossils point out that it was about the size of modern clouded leopard, but with longer legs, is yet another of those cats whose place on the feline family-tree has been widely debated. Experts believe that the length of the animal’s limbs is most likely an indication that it hunted primarily on the ground; however, there is no reason to believe that it did not climb trees as well.
Modern studies suggest this primitive cat is an early representative of the line that shaped modern cats – the earliest fossil found so far dates back to at least 25 million (2.5 crore) years. Fossil finds suggest there were numerous types of Pseudaelurus roaming during those days both in the Old and New Worlds of today, and all of them were definitely members of the ancestral house of modern cats. True saber-tooth came out quite early out of this house. Cheetahs (Acinonyx jubatus) also branched off early. After this the main line produced cats ranging in size from the cougar (Felis concolor) down. Members of Panthera group form a major offshoot, probably sprouting from the animals much like the clouded or snow leopard. They seem to have characteristics of Panthera, the cougar, or Felis group.
Prehistoric cats’ body structure had a lot to do with their hunting techniques. For instance, Nimravus with long limbs must have sprinted after its victims on the open plains. There is possibility that it might have preyed mainly on herbivores of modest size. Same seems true about an early contemporary of Nimravus, another lightly built false saber-tooth Dinictis.
Besides these sleek speedsters there were also huge-bodied cats that most likely hunted game that was big and slow moving. They must have relied on creeping close to the prey, taking advantage of the cover available to them, and then rushing the prey from short distance, and bringing it down in a short but violent fight. Typical example of these cats was Eusmilus, a bulky false saber-tooth. It stood out because it was lantern-jawed, which means its lower jaw protruded far downwards and outwards, like a heavy flange. This peculiar adaptation served a highly practical purpose. Covered by cheek, it sheathed the cat’s huge upper canines while the mouth was shut
Unevenly proportioned cats
The true saber-tooth lived long after the arrival of our own species. It was during the Pleistocene era, the great ice ages over and over again gripped the earth, with long warm periods between big freezes. Saber-tooth of this era was barrel-chested animal, with enormous shoulders, huge neck and back sloping toward the rear. Their front legs were muscular and long, but the hind ones were short and rather slight with bobtail. Some of these beasts looked so disproportionate that they seemed almost awkward, leading to speculation that they were scavengers that fed on the carcasses of dead animals rather than a fierce predators. Now the prevailing view is perhaps they were slow, but exceptionally powerful hunters lacking agility and swiftness. Their massive shoulders, chest, and front legs were so powerful that they could pin down creatures much larger than they, as their long canines repeatedly stabbed into the vital spot. The preys preferred by these cats seem to have been some of the largest mammals that ever walked the earth, like young mammoths.
Majority of these cats disappeared before the last of the ice ages. One, named Smilodon, survived until the end of glacial times, as recently as 10,000 year ago. It roamed the placid valley in the shadow of the Santa Monica Mountains, where modern city of Los Angeles stands today. This stump-tailed, lion-sized saber-tooth possessed canines of extreme length. Groups of these beasts swarmed about the famed La Brea Tar Pits – a waterhole during the Pleistocene, now a magnificent source of fossils and the centre of Los Angeles’ Hancock Park. Till now bones of more than 2,400 savage cats have been found here.
Smilodon wasn’t the most dreadful cat to be found in the region around La Brea. There was another beast, which was even bigger and more awe-inspiring, and was the ruler of the countryside in the real sense. Foreshadowing the future, it was not a prehistoric variety, but a feline of somewhat modern type, indeed, a member of the group Panthera.
Biologists are of the view that this huge cat used to inflict multiple stabbing wounds on the vital points resulting in the victim bleeding to death rather than killing it by biting on throat or neck. This strategy was to protect its gigantic canines. There are evidences that suggest it was a social animal and used to hunt in groups like the modern lions do. Though the appearance of this cat is still not very certain, it’s full skeleton has been recovered. It is claimed by the experts that it could have been as big as the biggest living tiger, may have been either an oversized lion, as obvious from certain skull features, or a gigantic jaguar. Since nothing more specific is available, it has been named the “great cat” Panthera atrox.
Panthera atrox had combination of well-proportioned legs with a huge body, and steel-like jaws that, although lacking dagger-like sabers of its contemporary, possessed incredible strength and biting power. It used to live in the open savannah habitat and roamed almost whole of North America at one time or the other during the Pleistocene. Its close relatives of equal size populated the Old World, which included the huge cave lion. It was a lot larger than the lions of today, but most probably the same species.
The emergence of felines such as the ‘great cat’ and cave lion lead the dominance of modern cats. By the ice ages they had spread all around the world and were taking shapes of animals we know today. Experts claim that even before the time of the glaciers, some cats similar to those of the present had evolved. Two million (20 Lakh) years ago, there were lynxes and cougars, but they were little different from those in existence today. Lynx’s early descendants appeared around 4 million (40 lakh) years ago for the first time and are given the name Issoire Lynx (Lynx issidorensis). This feline was larger than what we have in existence at present and is said to have more resemblance to those species belonging to the genus felis, notably in having shorter legs than the lynx of today.
Given the chaos and confusion over the origin of modern cats there is lot of variation in the scientific nomenclature of wild cats. Felines of one type or another are found in most parts of the world, except for Madagascar, Australia and its environs, cold desert of Antarctica, West Indies, and some islands.
Introduced on several islands including West Indies, domestic cat (Felis catus) has the ability to live on its own. This indicates its close relationship with its ancestors, supposed to be the African wildcat (Felis libyca) and possibly the European wildcat (Felis silvestris). They are from a large group consisting mostly of small cats that are very similar to the domestic ones, but also including a few large ones, such as cougar. It has equalled or exceeded in size by several other cats, including lions and tigers.
What wiped out sabertooth cats
Saber-toothed cats, American lions, woolly mammoths and other giant creatures apparently did not go extinct, a die-off called the Quaternary extinction, for lack of prey, fossil evidence suggests, contradicting a popular explanation for why they died. Even near their extinction, saber-toothed cats likely had enough to eat, researchers said.
“The popular theory for the megafaunal extinction is that either the changing climate at the end of the last ice age or human activity, or some combination of the two, killed off most of the large mammals,” said researcher Larisa DeSantis, a vertebrate paleontologist at Vanderbilt University in Nashville. “In the case of the great cats, we expect that it would have been increasingly difficult for them to find prey, especially if had to compete with humans. We know that when food becomes scarce, carnivores like the great cats tend to consume more of the carcasses they kill. If they spent more time chomping on bones, it should cause detectable changes in the wear patterns on their teeth.”
Teeth wear pattern
To learn more about the diet of saber-tooths, the fossil teeth of 15 saber-toothed cats (Smilodon fatalis) and 15 American lions (Panthera atrox), recovered from the La Brea tar pits in Los Angeles, were analyzed by the researchers. These specimens were about 11,500 to 35,000 years old. The research was published in the journal PLOS ONE in December 2012.
The investigation found the pattern of wear on the teeth of the saber-toothed cat most closely resembled those of present-day African lions, which sometimes crush bone when they eat. The wear pattern on American lion teeth, on the other hand, echoed that of the present-day cheetah, which deliberately avoids bones when it feeds. In addition none had extreme micro-wear like living hyenas that consume entire carcasses, bones included. This suggests that prey for these carnivores was not scarce — the animals were not gnawing their victims to the bone.
“Tooth wear patterns suggest that these cats were not desperately consuming entire carcasses, as was expected, and instead seemed to be living the ‘good life’ during the late Pleistocene, at least up until the very end,” DeSantis said.
Extinction of big predator
Past research of teeth from American lions, saber-tooth cats, dire wolves and coyotes from La Brea revealed they experienced three times the number of broken teeth of contemporary predators, hinting that they were having trouble finding prey and were thus urgently devouring or “processing” whole carcasses. This led scientists to suspect that climate change and human competition were making life tough for the big predators.
Contrary to the popular belief, DeSantis and her colleagues argue this high rate of damage seen in teeth more likely resulted during capture of prey instead of feeding on carcasses.
“We expected extinct carnivores to show evidence for extreme bone processing, based on the high number of broken teeth determined from prior research. Finding the complete opposite pattern was shocking!” DeSantis said.
The researchers noted that saber-toothed cats were about the size of today’s African lion, while the American lion was about 25 percent larger. They fed on giants such as mammoths and four-ton giant ground sloths. The fact these ancient carnivores and their prey were bigger than contemporary predators and their victims could help explain why the extinct cats had more broken teeth than their living brethren.
Specifically, larger teeth break more easily than the smaller once, so larger carnivores may be likely to break more teeth when attempting to take down larger prey. The researchers noted past studies that found the canines of a predator the size of fox can support more than seven times the fox’s weight before breaking, while a carnivore the size of lion can only support about four times its weight and the curved teeth of saber-toothed cats could only support about twice the animal’s weight.
“The net result of our study is to raise questions about the reigning hypothesis that ‘tough times’ during the late Pleistocene contributed to the gradual extinction of large carnivores,” DeSantis said. “While we cannot determine the exact cause of their demise, it is unlikely that the extinction of these cats was a result of gradually declining prey.”
In the presence of varied opinions on the relationships among felines, there is also lack of uniformity about which species qualify for the honour of “big cat”. After long debates and deliberations scientists have finally recognized only four species for the category of “big cats”. They are closely related and belong to the same genus, Panthera. This includes tiger (Panthera tigris), leopard (Panthera pardus), lion (Panthera leo) and the jaguar (Panthera onca). Now the question is why only these four have been chosen as the big cats? Interestingly many leopards and even some jaguars are smaller than individuals of species not included in the group of big cats. Answer is size alone is not the sole criterion to acquire the coveted status. Scientists assert the title should go only to cats capable of roaring and only the above four possess this quality.
Roaring by the felines is not related to their size; however, it has clear-cut relationship with the flexibility of the elongated and specially adapted larynx and hyoid apparatus. The case of snow leopard is unique in the sense that despite having hyoid morphology similar to roaring cats it cannot roar. When air passes through the larynx or the voice box on the way from the lungs, the cartilage walls of the larynx vibrate, producing sound. Lion possesses the longest larynx that is why it has the most robust roar. Big cats’ voice boxes can stretch more than those of other species, and thus generate a deep, throaty sound. This also enables the cats to gulp down chunks of meat the size of a football.
Tiger, which may weigh up to 600 pounds and attain a length of up to 13 ft., from nose to the tip of the tail, is the largest living cat. Lion, which is few inches shorter in length and also a couple of pounds lighter than tiger, comes second. Jaguar is on third place with a maximum length of nine feet and weight around 350 pounds. Leopard which is approximately the same length as the jaguar, but a little less heavier comes fourth on the list. The heaviest leopard is just over 200 pounds.
There are some experts who put two non-roaring, smaller cats within Panthera for the reason similarities in bones and behavior. These felines include snow leopards that seldom weigh more than 90 pounds, and the clouded leopards, hardly more than 50 pounds. Majority of scientists do not agree with this argument, hence classified each of the two independently, giving them the scientific names Uncia uncia and Neofelis nebulosa respectively.
It is commonly believed that leopards and jaguars share a common ancestry, centered in Eurasia a little over 2 million (20 lakh) years ago. Both spread westward into Europe, where it is recorded as Panthera gombaszoegensist, fossil remains of which have been dated at about 1.5 million (15 lakh) years.
Available evidences indicate that jaguar’s early generations also spread eastwards and reached North America through Bering land bridge. Both were larger and longer legged than the modern species. It is believed that after the emergence of lions in North America in the form of P.leo.atrox, jaguars were driven south into the heavily forested regions of Central and Southern America where as an adaptation to new habitat they began a gradual reduction in overall body size.
Fossil records suggest the lions came into picture considerably more recently as compared to others of the Panthera genus. The earliest records indicate the period around 750,000 years ago and stem from Western Africa. From here these animals entered and spread northward into Europe and Asia, where the Tuscany jaguar or Tuscany lion (Panthera toscana) and the Cave lion (Panthera spelaea) were found in the Northern Italy and the Balkans respectively. Lions did not stop their forward journey and they crossed over from Asia into North America and the American lion (Panthera atrox) spread south as far as Peru.
Cheetahs and their ancestors
Scientists claim that the ancestors of cheetah Acinonyx studeri were also found in North America from as far back as 2.5 million (25 lakh) years ago to as recently as 12,000 years in the smaller form of Acinonyx trumani. Cheetah that existed in America had numerous features of the modern cheetah, but it also had some evidences against a close relationship. There are also suggestions that the cheetahs living in North America had possible ancestral links with the puma. Early ‘Old World’ cheetah, Acinonyx pardinensis that existed in Europe, has close similarities to the present day cheetahs apart from being distinctly larger. Around 2 million (20 lakh) years old fossil remains of this animal have been found in France.
Some modern Wild Cats are found in similar habitats straddling many continents, like Leopard that ranges from the tip of Africa, across Asia and into China, but the majority of the species are indigenous to only one continent. Natural barriers like Atlantic Ocean also serve to divide animals of ‘Old World’ from those of the ‘New World’ – with the few exceptions like the Lynxes that can be found as distinct sub-species in both North America and Eurasia.
All cats share several qualities – physiological & behavioral
First carnivores, which gave rise to all living families, appeared about 10 million (1 crore) years after the dinosaurs vanished. These were weasel-like small animals and were differentiated from other primitive meat-eaters by several traits. One of them was a large premolar tooth in the upper jaw, and a molar in the lower, designed to cut and shear flesh. These teeth or carnassials remain a carnivore feature. The more primitive flesh-eaters, like opossum, have largely undifferentiated teeth.
Through evolutionary path, which is not very clear, the features of the feline family slowly appeared in some of the animals descended from the carnivore root stock. Although there are lots of noticeable differences among the various species of living cats, they still share quite a lot of important characteristics both physiological as well as behavioral. For instance, whatever their size may be, all cats have a form that is deep-chested and muscular, yet supple. Almost all have rounded heads, with a short muzzle. There is one exception and it is the lion, which possesses the famed leonine mane and it is sported only by the males.
Cats have a clear-cut advantage as hunting animals. Their eyes are set wide apart, giving them a broad field of vision. Furthermore their eye pupils adjust quickly to the changes in light levels by expanding and contracting. This is the reason they adjust rapidly to seeing in the dark.
Although cats are not entirely nocturnal animals but by and large they become active after sunset. They have special reflectors in their eyes, which help them make the most use of whatever light is available. In the eye of animals such as cats, the escaping light is reflected by a mirror-like layer of cells, called the tapetum, backing the retina. The light then bounces back to the retina, where it can be used. The eye-shine or chatoyance of a cat shown by the beam of a lamp at night is in fact the reflection from the tapetum. In addition to outstanding night vision cats also have superb hearing. Combination of these qualities makes them excellent night-time hunters. Cat’s whiskers, which are extremely sensitive, provide additional help in feeling their way through the dense foliage in jungle.
Whether walking, sprinting or even creeping cats travel on their padded toes. Their hind feet have four toes each, but the front ones have five each. All but the fifth front toe, which is small, make contact with the ground while the animal is walking. Curving from the toes are sharp claws that in all species except cheetah, are retracted into sheaths when not in use. Powerful jaws and sharp claws are for seizing the prey. Canines, especially the upper ones, are used to deliver fatal bites. The other twenty eight or thirty teeth are for chewing and scrapping meat from bones. The latter task is also performed by the sand-papery tongue.