Tigers are big cats that live a mostly solitary life, and therefor reflect these aspects in your dreams.
They live in the jungle in deep cover, camouflaged from other creatures. They look orange to us, but most other jungle animals are color blind so the tiger stripes blend perfectly with the surrounding leaves and foliage, making them practically invisible.
Tigers can be very unpredictable, seeming to be slow, sedate, then suddenly pouncing on their prey or swiping a paw at a person. In dreams tigers can symbolize this secretive, unpredictable nature and raw power. They can be a warning against the changeable nature of things or people, against provoking a metaphorical sleeping tiger or be cautious around new acquaintances.
Because they are cats, tigers can also symbolize sexuality and seduction, only with a heightened element of danger!