Earth & Sky

Special thanks to:

Dr. Ronald Tilson
Tiger Species Survival Program Coordinator Minnesota Zoo
Apple Valley, MN

Janet Tilson
Editor
Tiger Information Center

Author’s Notes:
Why is the mighty and fearsome tiger in danger of extinction? The main reason is habitat loss. All over Asia, forests have been cleared for timber, agriculture, and human settlements. There is little wild habitat left for the tigers and their prey. As a result, tigers sometimes intrude into human space, attacking livestock and, in rare instances, attacking humans. To protect their lives and livestock, people often exterminate tigers.

When wild habitat is reduced, what often results is pockets of forest surrounded by human settlements. This causes a problem called population fragmentation. Groups of tigers within an enclosed forest can only breed with each other, and not with other tigers over a wider range. The repeated inbreeding within a small group can create genetic problems such as birth defects and mutations that cause poor health.

Killing tigers is illegal in most parts of Asia. But poaching continues to be a major problem and in many areas, local wildlife departments are understaffed and underpaid, often unable to catch the culprits. Tiger parts are highly prized in some traditional Chinese medicine practices, and therefore, tiger parts fetch high prices on the black market. The tiger’s whiskers are believed to be a cure for toothaches, their eyeballs are used to treat epilepsy, the tail to treat skin diseases, and the most valued part of the tiger, the bones, are used to treat rheumatism, weakness, and paralysis. Although most of the demand for tiger parts come from practitioners of traditional Chinese medicine, people in other countries also believe in the medicinal value of tigers. In India, tiger fat is used for treating leprosy and rheumatism, and in Laos, tiger claws are used as sedatives. As a result of these demand, at least three subspecies of tigers are perilously close to extinction; as these tigers’ habitat shrinks and demand for their parts increases, the Sumatran, Siberian, and most endangered of all, the South China tiger, are disappearing in the wild.

Efforts, from local grassroots conservation efforts, to international organizations, many of them heroic, are underway to save the tiger. Governments and local people of many Asian countries that are the homes of tigers are being encouraged to set aside habitat for tigers and their prey, and educated to understand the value of tigers as part of a healthy wild ecosystem. Programs are underway to survey and study tigers in the wild, and establish sound breeding programs in zoos. With the rate of habitat loss, and the demand for tigers for medicinal purposes, the tiger’s prognosis does not look good. But given the many conservation efforts that are currently underway, no one is ready to give up on these majestic cats.

For information of what you can do to help save the tigers, check out:

The Tiger Information Center
http://www.5tigers.org/

World Wildlife Fund
Year of the Tiger
http://www.panda.org/resources/publications/species/yft/

Tiger Species Survival Plan
http://aza.org/Programs/SSP/ssp.cfm?ssp=75

Interview with Dr. Ronald Tilson of the Minnesota Zoo, coordinator of the Tiger Species Survival Plan.

E&S: What is the current status of tiger populations, is it getting better or worse?

Tilson: Numbers of tigers depend on the countries. In Russia, populations have increased in the past 5 years. In India, Indochina, and Cambodia, their numbers are decreasing dramatically. It’s difficult to pin a number on the population left in the wild. The 5000 to 7000 number was generated four years ago, and represented a best estimate. Since then, numbers have decreased dramatically.

E&S: Of the 5 subspecies, which are considered the most endangered and why?

Tilson: The South China Tiger is down to just a handful. Chinese biologists say there are between 10 to 40 left. They are in areas where we have little knowledge, that are restricted, and there are no natural parks set aside. They are found in a half dozen small reserves-a population fragmentation problem. In November 2000, the Chinese are starting field surveys to find them, get some numbers, status of the prey base, and establish a tiger preserve. Tilson’s team has done some work with South China zoo animals, working on programs for breeding them in captivity.

E&S: Will they be reintroduced?

Tilson: Not sure. These animals are a genetic insurance policy. We don’t want to cash in yet, but it is smart to have them around.

The other two tiger subspecies in trouble are the Siberian or Amur tiger, and the Sumatran tiger. In the Russian Far East, about 300 to 400 Siberian tigers exist, and their numbers are increasing. They are protected fairly well. But in Sumatra, there could be 400 to 500 in the wild, but their numbers are in dramatic decline due to political and economic chaos in Indonesia. There has been burning of forests, killing of tigers and their prey by villagers using poison and snares. The black market for tiger parts has risen significantly, and has become common today, compared to just a few years ago.

E&S: Given the remaining habitat, and projecting loss of habitat in the coming years, what is the prognosis for tigers?

Tilson: Bad to poor. Tigers need large intact habitat, and a good prey base. The current trend is that most large habitat areas become fragmented. Roads are built through them, and settlements and farms sprout up. Tigers and their prey are sensitive to this, and the animals retreat 5 to 10 kilometers away from settlements. This reduces habitat considerably. Three to four conservation groups are currently working with local governments, but are having little success, except for the Russian far east. In Russia, after the political upheaval, poachers went wild, but anti-poaching measures were stepped up, and the situation is now under control. This goes on in cycles, the status of tigers in the wild depends on economical and political stability of the country. In Indonesia, conditions in the country are at an all-time low in 50 years, and there is anarchy in the provinces, so the tigers are suffering.

E&S: Are captive-bred animals in zoos being used for reintroductions to places once occupied by tigers?

Tilson: In North America, three subspecies are being bred in zoos, and in Europe, 2 subspecies are being bred. These animals are being managed carefully. They could be a possible backup to revitalize and/or augment wild populations. Currently, there are no plans for reintroductions because there is no place for the tigers. You just have to do your best to keep the species going.

E&S: How is genetic diversity being controlled in zoo populations?

Tilson: All endangered species are under genetic and demographic management. There are 140 North American zoos in the breeding program. Tilson is on the tiger committee. They meet annually, making about 12 recommendations a year for breeding animals, and recommendations about transferring cubs to other zoos. This program is about 12 years old.

There are 150 Amur tigers in this program, and this captive population is considered mature and stable. It’s hard to improve on them, and they are almost exact replicas of wild populations.

There are 50 Sumatran tigers, and 25 Indochinese tigers, these tiger programs are young and in development, and there are not yet enough tigers in the program. These tigers, however, are doing better in captivity than in the wild.

The genetic management for breeding is not done to enhance certain traits. The most distantly-related animals are bred to increase genetic diversity.

E&S: Is disease a problem for wild populations?

Tilson: In Africa, lions catch distemper from the large numbers of herding dogs and livestock. But we don’t know what is happening with tigers, disease could be occurring but we just don’t know.

The Tyger
by William Blake

Tyger! Tyger! burning bright
In the forests of the night
What immortal hand or eye
Could frame thy fearful symmetry?

In what distant deeps or skies
Burnt the fire of thine eyes?
On what wings dare he aspire?
What the hand, dare seize the fire?

And what shoulder, & what art,
Could twist the sinews of thy heart?
And when thy heart began to beat,
What dread hand? & what dread feet?

What the hammer? what the chain?
In what furnace was thy brain?
What the anvil? what dread grasp
Dare its deadly terrors clasp?

When the stars threw down their spears,
And water’d heaven with their tears,
Did he smile his work to see?
Did he who made the Lamb make thee?

Tyger! Tyger! burning bright
In the forests of the night,
What immortal hand or eye
Dare frame thy fearful symmetry?

Background Information:
Tiger (Panthera tigris)

The graceful and powerful beauty of tigers, the awe and terror they evoke, have, for thousands of years, captured the imaginations of human civilizations. A year in the Chinese zodiac is dedicated to the tiger. Tigers are an important part of folklore and legend throughout Asia, like the matchmaking mountain spirit of Korea, and the opportunistic “Sang Harimau” of Malay folklore.

Yet these powerful predators are in deep trouble. In the early 1900s, there were an estimated 100,000 tigers in the wild. In 1996, that number had plummeted to between 5,000 and 7,000. And their numbers are continuing to decline dramatically.

Tigers are the biggest cats in the world. There are 5 subspecies, all found in Asia. They live in a variety of habitats ranging from the cold dry temperate woodlands of Siberia to the tropical rainforests of Southeast Asia.

Subspecies of Tigers

1) Bengal Tiger (Panthera tigris tigris) These tigers occur throughout India, but are also found in small numbers in southern Nepal, Bangladesh, Bhutan, and western Myanmar. They inhabit diverse habitats, from cold coniferous Himalayan forests, to the mangroves of the Sunderbans, to wet forests of northern India. Males average about 9.5 feet in length, from head to tail, and weigh about 480 pounds. Females are smaller, about 8 feet in length and 300 pounds. They prey primarily on wild deer and cattle.

2) Indochinese Tiger (Panthera tigris corbetti ) They are mostly found in the remote forests of Thailand, Myanmar, southern China, Cambodia, Laos, Vietnam, and Peninsular Malaysia. Indochinese tigers are smaller and darker than Bengal tigers, and have shorter and narrower stripes. Males are generally about 9 feet in length, head to tail, weighing 400 pounds. The smaller females are 8 feet in length, and weigh about 250 pounds. Their primary prey is wild pig, deer, and wild cattle.

3) South China Tiger (Panthera tigris amoyensis) This subspecies, found in central and eastern China, is the most endangered of all tigers and the closest to becoming extinct. Chinese biologists estimate about 10-40 remaining in the wild. They are small-built, the males measuring 8 feet from head to tail, weighing 300 pounds, and females measuring 7.5 feet and weighing 240 pounds.

4) Sumatran Tiger (Panthera tigris sumatrae) Found only on the Indonesian island of Sumatra, this tiger is found in habitat ranging from lowland to submountain forests.The smallest of all tiger subspecies, males measure 8 feet from head to tail, and weigh about 260 pounds. Females measure 7 feet and weigh about 200 pounds. Their coat is the darkest of all tigers, with closely-space broad black stripes. Their primary prey include wild pig and deer.

5) Amur or Siberian Tiger (Panthera tigris altaica) These tigers are found primarily in the woodlands of eastern Russia, with a few in northeastern China and North Korea. It is the largest of the tiger subspecies, with males measuring up to 10 feet 9 inches from head to tail, and weighing up to 660 pounds. The smaller females measure about 8.5 feet and weigh between 200 to 370 pounds. Compared to other subspecies, this tiger’s orange coloring is paler, and its stripes are brown instead of black. They feed primarily on elk and wild boar.

Sadly, three tiger subspecies have become extinct in the wild over the past 70 years. The Caspian tiger (Panthera tigris virgata) was once found in Afghanstan, Iran, Turkey, Mongolia, and the Central Asiatic region of Russia. It most likely became extinct in the 1950s. Two other extinct subspecies came from Indonesia: the Javan tiger (Panthera tigris sondaica) once lived on the island of Java and has not been seen since 1972. The Bali tiger (Panthera tigris balica) from the island of Bali was believed to become extinct in 1937.

Tiger Behavior

These great cats are solitary creatures. They each claim a territory, marking boundaries by spraying urine and scent gland secretions on trees and other natural structures. Often, they also leave scratch marks on trees. A male tiger’s range will often overlap with that of several female tigers. The size of a tiger’s territory depends on the availability of prey; in parts of India where prey is plentiful, a territory can range from 8 to 60 square miles, while in Siberia, the coldest and harshest part of the tiger’s range, a tiger’s territory could be as large as 400 square miles.

In the wild, tigers hunt by ambushing their prey, stalking them quietly, then pouncing on them from behind. They lunge for the prey’s neck or throat, severing the spinal cord in small or medium animals, and for large prey, clamping down with powerful jaws till the victim dies of suffocation. The tiger then drags its prey to a safe place to feed, sometimes taking several days to consume a meal. Many times, tigers will gorge themselves on a kill, eating up to 40 pounds of meat in one sitting. After that feast, they will not eat for several days.

Tigers are only seen together when they breed, or when a mother is raising her cubs. A female is ready to reproduce at 3 years of age, while a male matures a year later. When a female comes into estrus, she lets out loud roars, and sprays a pheromone-rich urine to advertise her readiness to mate. After mating, she is once more on her own; male tigers do not participate in raising their cubs. About 103 days after a successful mating, the cubs are born. Mother tigers usually produce 2 to 3 cubs, but one will die at birth. Newborns come into the world blind and helpless, weighing between 2 to 3 pounds, depending on the subspecies. For 6 to 8 weeks, the cubs rely on their mother’s milk for nourishment. After that, mother begins taking them to eat her kills, and starts teaching them the skills they will need to survive in the wild. By 18 months of age, the youngsters are able to hunt their own prey. Most tiger offspring will stay close to their mothers for 2 to 3 years. When the time comes to leave home, females tend to establish territories close to their mothers while males wander off farther away.

Additional References

The Tiger Information Center

World Wildlife Fund – Year of the Tiger

American Zoo and Aquarium Association – Species Survival Plan: Tiger

National Fish and Wildlife Foundation

Webpage containing stories about Sang Harimau from Malay Folklore

The Norton Anthology of Poetry
Revised Shorter Edition
1975 W. W. Norton and Company