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

Foraging Habits

As solitary animals, tigers generally hunt alone rather than in groups.  They are carnivorous animals who prefer to live in areas with dense vegetation to aid in their hunting as well as for their own protection.  Tigers do most of their hunting at night, where they primarily rely on their hearing and eyesight to locate their prey.  They crouch and quietly stalk their prey until they can situate themselves near enough to launch an ambush.  This stalking approach seems to be a way to save energy, since chasing down an animal is a much greater exertion.  They kill their prey with a bite to the neck or throat.  

Tigers like to drag their kill to an at least semi-covered area before they begin to eat.  With each kill, tigers eat an excessive amount and can then go for days without eating again.  This is beneficial because attacks are usually successful only once every 10-20 times.  This seems to be the trade-off for hunting alone.  Tigers get to eat their heart's content when they do get a kill, but they can't rely on a meal every day.  Interestingly, once tigers are finished with their meal, they cover up the remains in an attempt to hide it from other animals who may benefit from the leftovers. 

Female tigers with cubs must hunt more often to keep their cubs fed.  Though it isn't a regular occurrence, male tigers have been documented sharing their kill with a female and her cubs.  It doesn't seem to be clear why some males do this at certain times, but it is likely only in times of abundant resources.   

Resources:  http://www.indonesianfauna.com/tiger.php

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

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

http://www.tigers-world.com/tiger-feeding.html 

Territorial Behavior

Tigers are solitary animals and highly territorial.  They primarily live in home ranges that often overlap with a number of female home ranges, but exclude other males.  Female tigers usually remain within the same home range for their lifetime, but male tigers may establish new home ranges over the years.  Sometimes, tigers establish their own territories, which don't overlap with any others.  This decision primarily depends on the amount of prey in the area, which also influences the size of tigers' home ranges or territories.  Areas with a dense population of prey show smaller home ranges, but male tigers consistently have larger territories than females. 

Female tigers tend to establish themselves near the territory they grew up in, while male tigers set out on their own.  They either find an area not already occupied by other tigers, or challenge another tiger for the territory he has already established.  

In situations where tigers have home ranges rather than clear territories, they use intimidation rather than aggression when confronted with another male within their range.  Often, the intruding tiger with display a subordinate posture and the dominant tiger will allow him to stay in the range, as long as he keeps his distance.

Tigers mark their territory with scent and visual cues.  The most basic means of scent marking is urinating on trees or rocks surrounding the boundary of the territory.  Tigers produce a unique type of urine with a longer lasting scent for this purpose.  They also visually establish their territory by scraping out marks along the boundary.  

Sources: http://www.planetwildlife.com/information/species/tiger?section=behaviour

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

http://en.wikipedia.org/wiki/Tiger#Territorial_behaviour 

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

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

http://www.indonesianfauna.com/tiger.php 

Tigers in Entertainment

Since beginning this blog, I've begun to notice tigers in commercials and movies.  Given their solitary nature and  the obvious danger they can pose to humans, I wondered how difficult it is to train these animals.  When I began to research this, I found that there doesn't seem to be a scarcity of companies with trained tigers available for Hollywood.  Therefore, it seems that it can't be so overly risky or difficult that few can manage it.

  However, I found an interview with a professional tiger trainer, Dave Salmoni, who said that most trainers of big cats are eventually attacked.  He even said, "They will kill you if they get a chance.  They may share some of your emotions, but they won't have any problem with killing you if you make a mistake.  My cats will kill me, no problem, given the chance."  This reminded me of the Sigfried and Roy accident in 2003, when one of the male tigers attacked Roy.  There is still debate about whether the cat intended to hurt Roy or not, but either way, it proves that tigers are still wild animals, no matter how they are trained.


Yet many obviously continue to work with and train tigers for entertainment.  Michael Hackenberger, another longtime big cat trainer, says problems arise when handlers "refuse to accept the biological realities of big cats."  These animals do not form bonds with humans.  In fact, they don't even make lasting bonds with other tigers.  As long as handlers respect the boundary between them and the animals and take the necessary precautions, it seems that it is still possible to work with tigers.  Still, I would not want to be the one acting beside it.


Here are a few clips of tigers in entertainment.  

(A slightly less realistic depiction)

Resources:

http://dsc.discovery.com/convergence/tigers/stories/story11_02.html

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

Reproductive Behavior

Tiger subspecies are spread out over differing regions and climates, which effects patterns of reproduction. Thus, the following is an outline of the basic characteristics of reproductive behavior found across tiger subspecies, but specific details may vary between subspecies.  Female tigers reach sexual maturity around 3-4 years of age, while male tigers do not reach this point until they are 4-5.  Once reaching maturity, female tigers signal that they are in heat (which occurs most frequently during the cooler months) in a variety of ways, including secreting a specific scent and attracting attention through roaring and other noises.  These behaviors are meant to attract potential mates, who approach the tigress warily.  Tigers are solitary creatures and therefore require a slower mating process while they ascertain that no harm will befall them.  In some instances, tigers will fight over a mate both have claimed.  These fights continue until one tiger gives up or dies.  Tigers do not mate for life and take many different partners.  An interesting fact about female tigers is that they do not release an egg to be fertilized until mating has already begun.  

Once a female is pregnant, the male tiger is out of the picture and the tigress must take sole responsibility for her young.  The female tiger's gestation period is four months and the general size of the litter is approximately 3 to 4 cubs.  Female tigers care for their cubs until they are around 2 years old.  Because tiger cubs stay with their mothers for so long, there is usually a 2 year gap between births.

Photos: 

    http://gallery.neoseeker.com/Triforce%20of%20Wisdom/photostream/4237806607

http://www.treehugger.com/endangered-species/four-white-tiger-cubs-quadruple-cuteness-video.html

References:

http://en.wikipedia.org/wiki/Tiger

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

http://www.lairweb.org.nz/tiger/mating2.html

Zoo Visit

This past weekend I visited the San Diego Zoo and spent some time at the tiger exhibit.  Below is a picture I took of the tiger, who was surprisingly active during my visit.  In my previous experience, tigers at zoos and wild animal parks have always been fairly reclusive and difficult to observe.  This time, however, the tiger was trotting around and sat down right in front of us to chew a large bone.

It is my opinion that the San Diego Zoo does it's best to provide adequate living conditions for its animals, but any kind of captivity for wild animals seems less than ideal.  The exhibit for the tiger hardly seems spacious enough to allow for such a large, powerful animal to get a sufficient amount of exercise and exploration.  However, I understand the work many zoos do to help protect endangered species, which include all subspecies of tiger.  I trust that those who work at the zoo and design exhibits take into account what is in the best interest of the animals and hope that every animal in captivity is treated with respect and allowed the chance to live as naturally as possible.

Welcome!

On the off chance that anyone outside of Animal Psych reads this blog, let me explain what'll be going on here.  If the title wasn't clear enough, this blog's aim is to inform the reader on many different aspects of the tiger species. They've always been my favorite zoo animal, so I'm taking this opportunity to learn something about these animals beyond how cute they are.  I can't pretend that I know much yet, but we're going to learn together. To start us off, take a look at a few pictures to familiarize yourself with our topic of interest.  Next week I'll be back to dive into a little history of these great cats. Thanks for reading!

Photos: (1) http://en.wikipedia.org/wiki/Tiger  (2) http://www.mylot.com/w/photokeywords/tigers.aspx  (3) http://www.sodahead.com/fun/orange-tigers-or-white-tigers/question-2412749/?link=ibaf&q=&imgurl=https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_LmT9ssNfDVFstwVvLnit0smqJIxcwxk2n6Di4mw5BW8umLAXj-lKIJYYArpuinVtKYxX9thqfhcIOZYveHQpjpX6wo8yBxy9fvkPUJ-S3toEf6add3CjvSAwrAKxiXAqjxXl7q_T4ME/s1600/baby%252Bwhite%252Btiger%252Bwallpaper%252B1.jpeg