Weight: Siberian tigers are the heaviest subspecies at 500 or more pounds (225 kg), with males heavier than females. The lightest subspecies is the Sumatran; males weigh about 250 pounds (110 kg) and females around 200 pounds (90 kg).

Measurements: Depending on the subspecies, the head-body length of a tiger is about 41/2 to 9 feet (1.4-2.8 m). The length of the tail is 3 to 4 feet (90-120 cm). The foot pads vary in size with age, resulting in inaccurate estimates when used in censusing wild populations.

Eyes: Tigers have round pupils and yellow irises (except for the blue eyes of white tigers). Due to a retinal adaptation that reflects light back to the retina, the night vision of tigers is six times better than that of humans.

Claws: Like domestic cats, tiger claws are retractable. Tiger scratches on trees serve as territorial markers.

Stripes: No one knows exactly why tigers are striped, but scientists think that the stripes act as camouflage, and help tigers hide from their prey. The Sumatran tiger has the most stripes of all the tiger subspecies, and the Siberian tiger has the fewest stripes. Tiger stripes are like human fingerprints; no two tigers have the same pattern of stripes.

Life span: The life span of tigers in the wild is thought to be about 10 years. Tigers in zoos live twice as long.

Cubs: Tiger cubs are born blind and weigh only about 2 to 3 pounds (1 kg), depending on the subspecies. They live on milk for 6-8 weeks before the female begins taking them to kills to feed. Tigers have fully developed canines by 16 months of age, but they do not begin making their own kills until about 18 months of age.

Head:Often carries the Chinese mark of wang or king on the forehead.