Eyesight
Tigers have forward facing eyes rather than one on each side of their head. This provides binocular vision because each eye's field of vision overlaps creating a three dimensional image. Binocular vision enables them to accurately assess distances and depth which is extremely useful for maneuvering within their complex environment and stalking prey.
Tigers have more rods (responsible for visual acuity for shapes) in their eyes than cones (responsible for color vision) to assist with their night vision. The increased number of rods allows them to detect movement of prey in darkness where color vision would not be useful.
Tigers have a structure at the back of the eye behind the retina called the tapetum lucidum that enables them to have better night vision. This mirrorlike structure reflects light (that has not already been absorbed by the eye) back into the eye a second time to help produce a brighter image. The tapetum lucidum causes their eyes to glow at night when a light is shone on them.
Cats in general have a broad horizontal line of nerve cells near the central portion of their eye that enables them to have better peripheral vision. This characteristic is especially useful for hunting prey that is running across a plain.
Tiger eyes have large lenses and pupils that increase the amount of light let into the eye. This characteristic helps the tiger with night vision and when there are low light levels available.
Research suggests that cats in general are capable of seeing the colors green, blue and possibly red, just in less saturation or strength than we see them.
In addition to the upper and lower eyelids that protect the eye, cats and other animals such as crocodilians (alligators, crocodiles, etc.) have a nictitating membrane on each eye that helps keep it moist and removes dust from the surface.
In general cats require only about 1/6 the light humans do to see.
Touch
Tigers have a well-developed sense of touch that they use to navigate in darkness, detect danger and attack prey.
Tigers have five different types of whiskers that detect sensory information and are differentiated by their location on the body. Whiskers differ from guard hairs in that they are thicker, more deeply rooted in the skin and surrounded by a small capsule of blood. The root of the whisker displaces the blood when the whisker comes into contact with something thereby amplifying the movement. Sensory nerves detect this movement and send signals to the brain for interpretation.
The mystacial whiskers are located on the tiger's muzzle (snout) and are used when attacking prey and navigating in the dark. The tiger uses these whiskers to sense where they should inflict a bite. When navigating through darkness the tiger's pupils dilate to let more light enter the eye to increase their vision. The dilated pupils of their eyes assist their night vision but makes focusing on objects up-close difficult. The tiger's mystacial whiskers help it feel its way through the dark.
Superciliary whiskers are located above the eyes.
Cheek whiskers are located just behind the mystacial whiskers on the cheeks.
Carpal whiskers are located on the back of the tiger's front legs.
Tylotrich whiskers are located randomly throughout the body.
The facial whiskers of the tiger are about 15 centimeters (six inches) in length.
The facial area of the tiger has numerous sensory neurons that can detect even the slightest change in air pressure when passing by an object.
Hearing
The tiger's sense of hearing is the most acute all its senses and is mainly used for hunting. Their ears are capable of rotating, similar to a radar dish, to detect the origins of various sounds such as the high-frequency sounds produced by prey in the dense forest undergrowth.
Cats in general are more sensitive to high-pitched sounds than humans are. Cats may hear sounds up to 60 kHz whereas a human's upper auditory range is about 20 kHz. This sensitivity enables them to detect the high-pitched sounds emitted by prey and their movements.
Smell
The tiger's sense of smell is not as acute as some of its other senses and is generally not used for hunting. They have small amounts of odor-detecting cells in their nose and a reduced olfactory region in the brain that identifies various scents.
The tiger mainly uses its sense of smell for communicating information with one another such as territories and reproductive status.
Tigers, like other carnivores, have a Jacobson organ in the roof of their mouth. The Jacobson organ is a pouch-like structure located directly behind the front incisors. It has two small openings that direct scent particles from the air as the tiger inhales to nerves located within the structure. The nerves then transmit the message to the olfactory region in the brain that identifies the scent.
Tigers will exhibit a behavior called flehman, in which they pick up a scent on their upper lip and curl it upwards towards their nose to detect scents. This behavior makes the tiger appear to be snarling but without any sound.
Taste
Tigers seem to be able to taste salt, bitter and acidic flavors and to a lesser degree sweetness.
Cats in general possess only about 500 taste buds compared to a human's 9,000. Therefore taste buds are speculated to have a minimal role in their survivability.
