Extinct+Siberian+Tiger



===**__Prehistoric/Extinct Animal: // Smilodon - 10,000 to 1 million year period-- ---> Modern Animal: Siberian Tiger<---1,000 year period -Future Animal: Lesser Siberian Tiger// __** //Smilodon //, meaning ‘knife’ and ‘tooth’ in Greek was given the colloquial name ‘Sabre-Toothed Cat’ because of their distinct dental features. The prehistoric //Smilodon// existed 1 million to 10,000 years ago and is currently believed to be directly related to the current Siberian Tiger given the comparable features of the two cats. This section of the report will attempt to investigate the reasons behind the extinction of the //Smilodon// as well its adaptations and habitat.

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Scientific Classification Table
 * **Scientific Group** || // Taxonomy // || // Description // ||
 * **Kingdom** || // Animalia // || // Species of animal // ||
 * **Phylum** || // Chordata // || // Organisms with spinal chords // ||
 * **Class** || // Mammalia // || // Mammals nurtured with mammary glands // ||
 * **Order** || // Carnivora // || // Species that consumes meat primarily as their diet // ||
 * **Family** || // Felidae // || // Biological family of cats // ||
 * **Genus** || // Smilodon //  || // One category of the ‘long-canine’ cats including: [|Lions], [|leopard], tigers, and [|jaguars.] // ||
 * **Subfamily** || // Machairodontinae //  || // From the biological family of cats // ||

The //Smilodon// was believed to have existed in the late Quaternary period, a time when land mass’s had completely transformed itself from the original Pangaea, the once supercontinent was now multiple separated continents and somewhat appeared to be what the Earth now looked like (refer to figure). The spawning point of //Smilodon// was geographically located in North and Southern America at the Southern Hemisphere and relatively close to the equator, due to this geographical location; temperatures were on average at about 30 **° **C, in addition rivers or lakes were scarce in this area. The //Smilodon// was located on the top of the food chain, meaning that they did not have any predators like the modern day Siberian tiger. However, they did have different variations in their diet. The //Smilodon// hunted [|antelopes], deer’s, buffaloes and the ancestors of the modern day camel, and at situations, hunted [|mammoths] in packs. The //Smilodon// lived on large expanses of terrain where there were little shelter and was densely populated by the tall[| buffalo grass]that also exists in the modern day ecology of the Siberian Tiger.
 * __ Habitat: __ **




 * __Adaptations __: **

The long and sharp canine teeth has been proven to be one of the most functional structural adaptations that the //Smilodon// has developed, proof of this is that it still exists as one of the major adaptations of the modern day Siberian Tiger. The average length of a fully mature //Smilodon// canine could reach up to 28cm (11 inches) and had an estimated diameter of 2 – 4 cm. These long canines were deadly weapons that were originally used to tear apart the jugular vein of their prey to fatally wound the prey or to break the trachea of the prey so it died of suffocation; both these methods of killing involved the use of their teeth. And because their canines were used so very often, scientists discovered from fossils of these species that their teeth were extremely durable due to the tightly compacted bone cells that made up the structure of their teeth. In addition, the long canine teeth are also bent on an angle so that it is less likely for the //Smilodon// to damage its own jaw with its own teeth. Furthermore, without this pair of canines, the //Smilodon// would quickly die of starvation as it can get difficult to hunt without these canines, making survival even harder for them.
 * __Structural #1 – Long canine teeth and jaws __**

A possible environmental factor that caused this adaptation is that the retractable claws of the //Smilodon// were beginning to wear off because they were used in both marking territory and hunting, alternatively the //Smilodon// adapted to the new method of using their teeth to attack their prey. Therefore, over time due to natural selection, the //Smilodon// passively began developing stronger, longer, and sharper canines. Another interpretation is that the thick hides and fat layers of animals that lived during this time made the //Smilodon// elongate and sharpen their teeth even more.

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Similar to the Siberian Tiger, the //Smilodon// possessed short muscular limbs to aid in hunting. However, unlike the Siberian Tiger, the //Smilodon// had short hind-limbs instead of long limbs. On the hind-limbs of the //Smilodon// locates the most powerfully built muscle throughout the body of the //Smilodon//, the adductor muscles. It is by this specific muscle that the //Smilodon// can leap over 12 metres with the addition of a sprint. This physical ability of the //Smilodon// allows it to act as a battering ham, multiplying its inflicted force to twice its original capabilities, therefore enabling the //Smilodon// to take down relatively large prey including the masterdon and [|mammoth] and provide itself with meat to survive.
 * __Structural #2 – Short and muscular limbs __**

A possible environmental aspect pushing this adaptation is the fact that a majority of the //Smilodon//’s prey are relatively larger and heavier than of the //Smilodon// itself, and by this aspect, the //Smilodon// has developed powerful muscles on their legs to be compatible with its prey.

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">Another feature that the //Smilodon// and the Siberian Tiger both share is the skill to retract their claws. This adaptation may not sound important, but it can contribute to the hunting successes. Similar to the modern day Siberian tiger, the //Smilodon// relies on stealth and by retracting their claws, the sound of their claws tapping on the floor would be minimised as well as the chances of being heard by their prey. Another advantage of the retractable claws is that if they could not be retracted, they can easily erode after weeks of walking on rocky terrain, hence without them, it would be extremely hard to get grip of prey during a hunt. Hence without the claws, hunting could be unsuccessful and lead to starvation and then the inability to survive.
 * __<span style="font-family: 'Calibri','sans-serif'; font-size: 27px; line-height: 115%;">Structural #3 – Retractable Claws __**

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">The possible environmental pressure causing this is that deer’s and antelopes, both of which are preys of the //Smilodon// and have evolved to have particularly sound sensitive ears, meaning that the slightest sound could lead the //Smilodon//’s prey getting away, also noting that //Smilodon//s are incapable of running long distances due to their bulk body. Therefore due to this environmental factor, the //Smilodon// was pressured to develop retractable claws to assist them in hunting.

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">The prehistoric //Smilodon// is thought to be more sociable with other tigers in comparison to the modern day Siberian Tiger. Similar to the behaviour of lions, the //Smilodon// prefers to live and hunt with other //Smilodon//s in small packs, usually in group of 2 to 4 where at least one is female. Hunting in packs is arguably one of the most controversial behavioural adaptations that the //Smilodon// has, and is also one that the modern day Siberian Tiger does not have. The advantages of hunting in groups include:
 * __<span style="font-family: 'Calibri','sans-serif'; font-size: 27px; line-height: 115%;">Behavioural #1 – Living/Hunting in packs __**

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">1. Increased probability of successfully seizing prey during hunts <span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">2. Are able to confront larger animals for more meat (e.g [|Mammoths]) <span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">3. Higher chances of finding a mating partner.

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">On the other hand, due to this behavioural adaptation, young cubs may grow up to be accustomed to this lifestyle and be dependent on other //Smilodon//’s to survive. Hence if the independent //Smilodon//’s in the pack die off, the remaining //Smilodon//’s that are dependent on the independent //Smilodon//s would quickly die off.

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">A possible environment that pressures this adaptation is that there was a period of time where smaller sized prey (e.g antelopes) were hunted excessively, resulting in a decline in population of that specific species. Hence when that species of prey was scarce, the //Smilodon//was forced to hunt bigger preys. Nevertheless, [|mammoths] were too hard to hunt by one individual //Smilodon//, and through this event the individual //Smilodon// developed to hunt with other //Smilodon//’s to achieve a mutual target. <span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 0px; overflow: hidden;">

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">The //Smilodon// is incredibly territorial by nature like the modern day Siberian Tiger. Although their territory size is unknown, it can be predicted that //Smilodon//s possess twice as much land as the Siberian Tiger (about 120 to 200 <span style="color: black; font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;"> km 2  <span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">) due to not having land limitations like the Siberian Tiger. Additionally, male //Smilodon//s are relatively welcoming with females into their territory and rather aggressive towards Male //Smilodon//s that trespasses their territory. If this situation occurs, the owner of the land would not abandon their land without a fight, the fight usually goes on until either one of the //Smilodon//s surrender, where the winner claims the new land to be theirs.
 * __<span style="font-family: 'Calibri','sans-serif'; font-size: 27px; line-height: 115%;">Behavioural #2 – Territorial __**

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">This behavioural adaptation is useful for the survival of the //Smilodon// because it allows the //Smilodon// to have access to valuable natural resources like rivers and lakes or specific areas with more prey only available to the “owner”.

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">An environmental pressure that could have caused this adaptation is that resources in the land including food could have become limited in specific areas. And so, Siberian Tigers may tend to keep this area private to themselves and defend the territory so that it is limited only to itself and allow it to survive.

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">The species of //Smilodon// had been wiped out and pushed to the brink of extinction during the [|Ice Age] of the [|Pleistocene period], of which occurred 1.8 million years ago. There are many scientific hypotheses that attempt to explain the reason behind the extinction of the //Smilodon//, and here are 2 of most reasonable predictions.
 * __<span style="font-family: 'Calibri','sans-serif'; font-size: 27px; line-height: 115%;">Selection Pressure __**

<span style="font-family: 'Calibri','sans-serif'; font-size: 19px; line-height: 115%;">The first assumption was that because the //Smilodon//’s habitat was generally hot and limited in water resources, the //Smilodon//’s developed short fur coats to minimize heat insulation in order to reduce perspiration to stay hydrated. Because of this structural adaptation, the population of //Smilodon// only had an ineffective and thin fur coat to insulate heat during the drastic drop in climate, furthermore the climate change was too sudden and the //Smilodon// did not have enough time to evolve and develop thick coats to adapt to the cold climate, and ultimately resulting in the population of //Smilodon// tigers dying in the cold. Another scientific interpretation is that the ratios of predators and prey in the food chain could have been disrupted or imbalanced in the course of the ice age era. This event could possibly directly relate to the //Smilodon// because the prey that the //Smilodon// hunted could also have been pushed towards extinction due to similar adaption issues. In addition, the species of //Smilodon// requires a daily intake of 30-40 pounds of meat in order to survive, and during this cold era not only was food scarce but so was water. Both of which are essential factors that the //Smilodon// Tiger cannot live without.


 * <span style="color: #9bbb59; font-family: 'Calibri','sans-serif'; font-size: 37px; line-height: 115%;">Bibliography **

<span style="font-family: 'Calibri','sans-serif'; font-size: 15px; line-height: 115%;">[|http://www.bbc.co.uk/nature/life///Smilodon//]
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<span style="font-family: 'Calibri','sans-serif'; font-size: 15px; line-height: 115%;">[]
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<span style="font-family: 'Calibri','sans-serif'; font-size: 15px; line-height: 115%;">[] <span style="font-family: 'Calibri','sans-serif'; font-size: 15px; line-height: 115%;">[|http://en.wikipedia.org/wiki///Smilodon//]
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<span style="font-family: 'Calibri','sans-serif'; font-size: 15px; line-height: 115%;">[|http://www.enchantedlearning.com/subjects/mammals///Smilodon/////Smilodon//printout.shtml] <span style="font-family: 'Calibri','sans-serif'; font-size: 15px; line-height: 115%;">[|\]
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