A powerful hunter with sharp teeth, strong jaws, and an agile body, the tiger is the largest member of the cat family. It is also the largest land-living mammal whose diet consists entirely of meat. The tiger's closest relative is the lion. Without the fur, it is difficult to distinguish a tiger from a lion. Like a human fingerprint, no two tigers have the same pattern of stripes on their coats.
Tigers range in size from the diminutive Sumatrans to the large Amur tigers. Sumatran females weigh between 165 and 242 pounds (75 to 110 kilograms) and males weigh between 220 and 310 pounds (100 to 141 kilograms). The largest mainland tiger females weigh between 220 and 352 pounds (100 to 160 kilograms) and males weigh between 396 and 570 (180 to 259 kilograms). Total length ranges from seven to 12 feet (2.1 to 3.7 meters).
The tiger's current distribution is a patchwork across Asia, from India to the Russian Far East. Tigers require large areas with forest cover, water and suitable large ungulate prey such as deer and swine. With these three essentials, tigers can live from the tropical rainforests of Sumatra and Indochina to the temperate oak forest of the Amur River Valley in the Russian Far East
Tigers can communicate with one another by rubbing heads, roaring and grunting. Scent marks and visual signposts, such as scratch marks, allow tigers to track other tigers in the area, and even identify individuals. A female tiger knows the other females whose territories abut hers; in many cases, a neighbor may be her daughter. Females know their overlapping males (and vice versa) and probably know when a new male takes over. All tigers can identify passing strangers. So, solitary tigers actually have a rich social life; they just prefer to socialize from a distance.
Tigers are built to kill large prey. Their hind limbs are longer than their fore limbs, enabling the tiger to jump long distances. Tigers have heavily muscled forelimbs and shoulders, and paws equipped with long, retractable claws, which enable them to grab prey and drag it to the ground to deliver a killing bite with powerful jaws and long canines.
While other cats are able to swim, tigers are willing swimmers who often go in the water to escape flies or cool off, and can easily cross rivers and lakes 5 miles (8 kilometers) wide.
In the wild, tigers prey primarily on wild boar and other swine, and medium to large deer such as chital, guar, red deer and sambar. When near human development, tigers also kill domestic animals such as cows and goats.
Tigers depend less on smell and more on keen eyesight and acute hearing to ambush and capture prey, primarily between dusk and dawn. Unlike lions that hunt in prides in open country, the solitary tiger prefers to hunt in the cover of dense foliage. Tigers can travel from 6 to 20 miles (9.6 to 32 kilometers) in a night in search of prey.
A typical predatory sequence begins with a slow, silent stalk. A lightening fast rush to close the gap follows when the tiger is within striking distance from its prey, about 30 to 35 feet (9 to 11 meters). The tiger charges and grabs its prey in its forepaws, brings it to the ground, and finally kills the animal with a bite to the neck or throat. Large prey is bitten in the throat and usually dies from suffocation. Smaller animals are killed with a swift bite to the back of the neck. The carcass is then dragged to a secluded area where it is consumed. A tiger eats 30 to 40 pounds (13.6 to 18 kilograms) of meat in an average night, and must kill about once per week. Catching a meal is not easy; a tiger is successful only once in ten to 20 hunts.
At the Smithsonian's National Zoo, tigers eat ground beef. Twice a week, they receive knucklebones or beef femurs and once a week they receive rabbits, which exercise the cats' teeth and jaws.
Female tigers are sexually mature at about 3 or 4 years of age and males at about 4 to 5 years. Mating may occur any time during the year, but most frequently takes place from November to April. Females enter estrus every three to nine weeks and are receptive for three to six days. A male and female meet only during this brief time to mate; however, he may stay in the area. The female tiger is an induced ovulator, meaning that her ovaries do not release eggs until mating occurs. After a gestation period of about 3.5 months, the female tiger gives birth in a secluded den to two or three, blind and helpless cubs. Litters may range from one to six cubs. The female rears the cubs alone.
Cubs weigh just over 2 pounds (0.9 kilograms) at birth and can nurse up until they are 6 months old. Depending on the food supply the cubs can start eating meat as early as a month. After a week or two, the cub's eyes open and its first teeth begin to grow. During the next 18 months, they gradually become independent and follow their mother on hunts. At about two years of age, the young tigers strike out alone to find their own territory. Females may establish a territory adjacent to that of their mother, or even take over part of their mother's territory. Adult females generally produce a litter every two years.
The wild life span is ten to 15 years and can reach 20 years in human care. In the wild, most tigers do not live as long as 12 years. Only half of all cubs survive to independence from their mother; only 40 percent of these survivors live to establish a territory and begin to produce young. The risk of mortality continues to be high even for territorial adults, especially for males, which must defend their territories from other males.
Scientists have classified tigers into nine subspecies: Bali, Java, Caspian, Sumatran, Amur (or Siberian), Bengal, South China, Malayan and Indochinese. The first three of these subspecies are extinct, and the six remaining are endangered or critically endangered. Today, only an estimated 1,500 to 3,200 tigers exist in the wild (300 to 400 Sumatran tigers) and less than 200 in North American zoos. The future existence of tigers in the wild is in jeopardy.
For decades, Smithsonian Conservation Biology Institute scientists have studied tigers to understand their behavioral ecology and the most effective ways to protect them.
In collaboration with USAID and local partners in Bangladesh, SCBI scientists are collecting and analyzing a wide range of field data on tigers, prey and mangrove habitat, including through camera-trap studies to estimate tiger populations. To support and assist management of this project, rangers are trained and given equipment to patrol the forest to prevent poaching and mitigate human-animal conflict.
Smithsonian efforts to save tigers began in 1972 with the Smithsonian-Nepal Tiger Ecology Project. In the 1990s scientists began approaching tiger conservation as a complex problem stretching across borders, requiring the cooperation of many partners.
In 2008, the Smithsonian Institution joined the World Bank Group and the Global Environmental Facility to launch the Global Tiger Initiative, designed to stabilize and restore wild tiger populations to save the species from extinction. As a member of the GTI, SCBI scientists work with policy makers and practitioners across Asia and around the world to save tigers.
At the Tiger Summit in St. Petersburg, Russia, in 2010, leaders of 13 tiger-range countries met with international science and conservation experts, including SCBI scientists, to do what had never been done before: create a comprehensive strategy to save tigers. At the Summit, they adopted the first-of-its-kind Global Tiger Recovery Program (GTRP). Simultaneously, SCBI staff worked with individual countries to develop National Tiger Recovery Priorities.
As part of the GTRP, the Smithsonian prepared a Global Support Program in Capacity Building and Knowledge Sharing through regional training programs in Asia and Core Learning Programs on conservation best practices. They have held courses and workshops for frontline practitioners in protected tiger-range areas, training hundreds of rangers, foresters and habitat managers to adopt the latest conservation and Spatial Monitoring and Report Tool (SMART) patrolling practices, with a focus on preserving and increasing wild tiger populations.
SMART patrol training courses have been held in Thailand, Nepal, Indonesia and Malaysia. Using state-of-the-art techniques, the training has helped create more effective measures against wildlife poaching and the illegal trade and trafficking of live tigers and tiger parts.
Today, follow up projects like SCBI’s Tiger Conservation Partnership Program help Malaysia share information with its neighbors about effective ways to identify and protect tiger habitats in the face of rapid infrastructure development. Its knowledge exchange platform, WildTigers Listserv, has more than 500 tiger conservation professionals as members.
The Smithsonian's National Zoo has two Sumatran tigers, a female named Damai and a male named Sparky.
A male Sumatran tiger cub was born at the Zoo on July 11, 2017, and was later transported to the San Diego Zoo Safari Park, where he currently lives and thrives with another young male tiger cub.
When the Smithsonian's National Zoo's cub was just 19 days old, mother Damai began displaying aggressive behaviors toward him when he attempted to nurse. It quickly became evident to animal care staff that Damai was either not producing enough milk or had stopped production altogether. On Aug. 2, 2017, the Zoo's Great Cats team began providing support to the cub through supplemental feeding.
The cub remained in good health, and keepers continued to reintroduce him to Damai while providing supplemental feedings. Damai continued to care for the cub, was attentive to his needs, groomed him and socialized with him. However, on Aug. 23, 2017, her behavior changed again indicating she had entered estrus. She began to exhibit aggressive behaviors toward her cub, including growling, barking and biting at him.
Keepers separated Damai from her cub and gave them visual access to one another through a “howdy door.” While the cub’s behaviors clearly demonstrated that he was interested in spending time with his mother, she unfortunately did not reciprocate. He would “chuff”—a friendly tiger social greeting—and she would not respond. Knowing that the likelihood of a successful reintroduction diminished with each passing day that Damai and her cub did not socialize, the Zoo’s animal care staff made the decision to transfer the cub, and he was transported to the San Diego Zoo Safari Park on Sept. 11, 2017.