Evolution

Kingdom: Anamalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Carnivora
Family: Felidae


This is the beginning of the taxonomy of the tiger. The family of Felidae is broken down into three subfamilies.  Tigers are a member of the subfamily Pantherinae.  Within this subfamily is the tiger's genus, Panthera.  The other members of this genus are lions, leopards, and jaguars.  All of these cats share the ability to roar.  Even the species of tiger can be broken down into eight subspecies, five of which are still alive today.  According to the fossil record, Miacoids are the tiger's oldest ancestors.  These were tree-dwelling cats, much smaller than the big cats of today.  


The oldest cat is the Proailurus, dated to around 30 million years ago.  However, it was around 20 million years ago when the Pseudaelurines appeared.  These are the cats considered to be the direct ancestors to all modern cats.  


Within their genus, lions, jaguars, and leopards all have more in common with each other than they do with the tiger.  This indicates that the tiger probably diverged in the evolutionary tree earlier than the other members of its genus.  


The recent discovery of a skull 2.5 million years ago that relates to the modern cat showed that tigers have not evolved all that much.  The skull was extremely similar to that of a modern tiger, proving that the tiger was such a well-equipped predator from the beginning that not many adaptations were necessary.  This goes to show that what we talked about in class is true.  Evolution is not about becoming more and more advanced, it's about finding what works in an environment and sticking with it.  
   

Resources:

http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0025483

http://www.seaworld.org/animal-info/info-books/tiger/scientific-classification.htm

http://news.nationalgeographic.com/news/2011/10/111018-fossil-tiger-skull-panthera-science-oldest-china-evolution/

Tigers in Culture

Tigers have long been a part of America's popular culture, from Tigger in Winnie the Pooh to Tony the Tiger on Frosted Flakes boxes.

But other cultures have a special place for the tiger as well.  The tiger is the national animal for many Asian countries.  In Chinese culture, tigers are highly regarded for the contribution their body parts make to traditional medicine.  Their life-saving qualities make them a very important animal which has inspired many works of art and literature.  The Chinese calendar even acknowledges the Year of the Tiger.  In India, the tiger is considered a symbol of power and beauty.  The animal is a part of the Hindu religion's mythology and is respected for it's role in maintaining the balance of the ecosystem.

Sources:

http://www.wwfindia.org/about_wwf/priority_species/royal_bengal_tiger/faq/
http://www.tigers-world.com/tigers-in-culture.html
http://www.tigersofindia.com/Tigers-in-literature-and-popular-culture.php
http://en.wikipedia.org/wiki/Tiger_in_Chinese_culture

Predatory and Anti-Predatory Behavior

Tigers have few enemies in the wild, thus they rarely need to exhibit anti-predatory behavior.  When plenty of prey is available, tigers are not ones to risk their safety by going after very large prey.  They like to stick with sure bets unless they are suffering from starvation.  Tigers most commonly prey on deer and wild pigs, but often prey on other large and medium sized animals.  However, if the opportunity arises, tigers will go for smaller prey such as monkeys, fish, and even large lizards.

As I mentioned in the foraging post, tigers are nocturnal hunters who rely on the element of surprise when attacking their prey.  With their massive body size, they generally overpower their prey with sheer force before breaking the neck with a fatal bite.  Tigers do not chase their prey for long, finding it more efficient to search for another target rather than exerting their energy in a chase.  According to one source, tigers hunt and kill an average of fifty deer-sized animals each year.

Tigers have also been known to drive other animals away from their own kills, thus taking advantage of the food source without even having to attack.  As far as attacks on humans go, it seems that tigers are not often voluntary hunters of humans.  They generally only attack when they are threatened and often don't eat the humans they kill.  However, as humans continue to encroach on tiger habitats, attacks have become more frequent.  This is a result of a reduction in the prey population and the closer contact between humans and the animals.

Sources:
http://www.seaworld.org/animal-info/info-books/tiger/diet.htm
http://www.seaworld.org/infobooks/tiger/diettiger.html
http://education.nationalgeographic.com/education/multimedia/tiger-prey/?ar_a=1&ar_r=999

Tiger Habitat

Tigers are found throughout Asia, but are most heavily concentrated in India and Nepal.  Different subspecies of tiger are found in different areas, and tigers can adapt to a fairly wide range of environments.  Their environments must provide plenty of coverage so tigers can stalk their prey and find shade, so they are usually found in rainforests, swamps, and grasslands.  Tigers defy the stereotype of cats by actually enjoying the water.  They are strong swimmers and spend much time lounging in the water to escape the heat.  Here is a video of Odin, a white tiger who not only lounges in the pool, he dives underwater to retrieve food!

Tigers also must find an area with a dense population of prey.  This is one of the biggest problems facing tigers today.  As humans continue to take over their land, tigers have a harder time hunting and subsequently die off.

Sources:
http://www.miamisci.org/youth/unity/Unity1/Jasmine/pages/habitats%20of%20the%20tigers.html
http://www.wildlywise.com/tiger_habitat.htm
http://www.seaworld.org/animal-info/info-books/tiger/habitat-&-distribution.htm
http://animals.howstuffworks.com/mammals/swimming-tigers.htm

Scholarly Article

Environmental Effects on the Behavior of Zoo-housed Lions and Tigers, with a Case Study of the Effects of a Visual Barrier on Pacing is a journal article written by Meredith J. Bashaw, Angela S. Kelling, Mollie A. Bloomsmith,and Terry L. Maple.  This article discusses animals in captivity and whether changing captive environments results in a change in the behavior of tigers and lions.  The researchers observed two Sumatran tigers.  The tigers were placed into two different exhibits, one larger with access to places to hide from the public and one smaller with no areas of cover.  Behaviors were divided into the categories of resting, resting but awake, pacing, and any other behaviors.  It was found that there were significant differences in the amount of activity the animals displayed at different times of the day, with the morning being the most active time for them.  There was no significant difference in behavior found between the larger and smaller exhibit.  

The researchers seemed to be concerned with the fact that most zoo visitors observe the animals during their peak of inactivity, and suggested that information about their activity schedule be made more readily available to the public.  They also mention that pacing behavior seems to indicate to the public that the animal is feeling stressed or bored.  The researcher found that the number of  areas of cover the animal has in his exhibit greatly effects the amount of pacing in small cats.  However, in a subsequent case study used to determine how the placement of barriers would effect tiger behavior, the researchers found that the placement of the barrier did not impact pacing.  This led them to believe that pacing may have more to do with a behavior like feeding rather than social situations, or that visual stimuli is not the only thing impacting the animal.  Auditory and olfactory cues may be just as significant. 

Sources:

Environmental Effects on the Behavior of Zoo-housed Lions and Tigers, with a Case Study of the Effects

of a Visual Barrier on Pacing by Meredith J. Bashaw et al.

Tiger Cubs!

Today I want to talk about tiger cubs.  Like us, they are born helpless and must rely on their mother for protection and nourishment.  They are blind upon birth and don't reach their full visual capacity for weeks.  It isn't until they reach the age of two that they can even begin hunting for themselves.  Because of the great amount of time and energy it takes to feed extra mouths, a tigress can generally only keep two of her cubs alive, no matter her initial litter size.

To protect herself and her cubs, a tigress finds shelter in dens where visibility from the outside is low.  This is important because the young tiger cubs must be left alone while their mother is hunting.  By about eight months, the tiger cubs can follow their mother on hunts and learn the tricks of the trade. 

Once they are around two years old, tiger cubs become independent of their mother.  Males roam further from their mother's territory than females and eventually establish their own territory once they reach full maturity. 

Resources:

http://www.seaworld.org/animal-info/info-books/tiger/birth-&-care.htm

http://lifeevolution.wordpress.com/evolution/tigerbehavior/

http://www.sandiegozoo.org/animalbytes/t-tiger.html

http://www.seaworld.org/infobooks/tiger/behavtiger.html

Pictures:

http://www.deviantart.com/download/61945407/white_tiger_cubs_by_buggy12.jpg

http://awtlblog.vitsco.com/wp-content/uploads/2003/10/Sumatran-Tiger-Cubs.jpg

Conservation Status

Of the nine subspecies of tigers, three are already extinct.  All six remaining subspecies of tigers are currently considered endangered animals.  There are many different estimates of the number of wild tigers alive today, ranging from 3,500 to as low as 2,000.  This number has gotten so low mainly as a result of poaching and habitat destruction.  According to the World Wildlife Fund, tigers have lost 93% of their historic range due to habitat destruction.  Tiger fur is the primary target of poachers, but according to one article, all parts of the tiger are in demand for use in traditional Asian medicine.  Tigers are even part of the illegal pet trade.  However, many organizations and governments in countries around the world have begun to work towards protecting tigers from extinction.  Movements such as India's Project Tiger establish tiger reserves as protection for the animals.  Various laws have made poaching and the pet trade illegal, as well as establishing rules for the protection of the forests tigers inhabit.  Many countries also have laws preventing the sale of products made with tiger parts.  Even zoos help with breeding programs and by educating the public on the current threat facing tigers.  Thus far, these measures have been largely successful, but the work is not done.  With numbers this low, tigers still need a lot of help.  If you are interested in learning more or donating to the cause, I recommend visiting the World Wildlife Fun website.  An Animal Planet survey found that tigers are the world's favorite animal!  If we want to keep these and the many other endangered animals around, we've got to keep educating ourselves and others and taking a stand for animals who can't help themselves.

Resources:
http://www.sandiegozoo.org/animalbytes/t-tiger.html
http://www.planetwildlife.com/information/species/tiger?section=other
http://www.indonesianfauna.com/tiger.php
http://www.seaworld.org/animal-info/info-books/tiger/conservation.htm
http://www.worldwildlife.org/species/finder/tigers/threats.html

Image:
http://www.thestar.com/news/world/china/article/762492--china-s-year-of-the-endangered-tiger