Both male and female tigers exhibit a range of fascinating behaviors that are of great interest to biologists. Scientists who study captive tigers can easily determine a tiger's gender by examining its reproductive organs. Scientists studying tigers in the wild must keep a safe distance, which makes it difficult for them to distinguish between male and female tigers. Fortunately, they have methods they can use to determine a wild tiger's gender.
TL;DR (Too Long; Didn't Read)
When studying tigers in the wild, scientists can't always get close enough to determine a tiger's gender easily, but when they observe a tiger's size, body composition and behavior, they can determine the gender.
Differences in Size
Tigers are the largest cats on earth. Male Bengal tigers – the largest subspecies – can weigh in at a whopping 600 pounds, while females usually stay around 300 to 350 pounds. It stands to reason that differences in size help scientists determine whether they are studying a male or female tiger.
Even determining a wild tiger's size can be tricky. Obviously, scientists cannot weigh wild tigers to record their weight. Scientists also cannot usually compare a tiger's size against another tiger because unlike social cats such as lions, tigers are usually solitary. Instead, researchers must measure certain objects in the tiger's usual surroundings and observe how much larger or smaller a tiger is than those objects. Since females are usually smaller than males, this method can help scientists figure out a tiger's gender.
Differences in Body Composition
There are some visible differences in body composition between male and female tigers, though they can be difficult to spot. Male tigers tend to have slightly longer tails relative to their body size than females. Photographs may help determine the length of a tiger's tail when combined with information about the tiger's overall size. Males also have larger front paws relative to their body size. Measuring a tiger's paw prints can help scientists determine gender.
Since only female tigers can become pregnant, it is useful for scientists to watch for signs of pregnancy during a tiger's mating season. Signs of pregnancy include a swollen abdomen and visibly protruding teats.
Differences in Behavior
Though male and female tigers exhibit many of the same behaviors, there are behaviors that are unique to males or females. Males roam larger territories than females. By measuring the range over which a tiger roams, a scientist can make an educated guess as to its gender. Male tigers also tend to be more territorial than females. Even though both males and females fight other tigers that wander into their territory (unless it is mating season), males tend to mark their territory more often than females. Tigers mark their territory by lifting their tails and spraying objects with a mix of urine and gland secretions. The scent of the spray warns other tigers not to go near. Females may go several days without spraying their territory, while males spray at least once a day.
Male tigers do not help raise their cubs. If a wild tiger is seen with a cub in tow, it is almost certainly a female. Females raise their cubs alone until the cubs reach 24 to 30 months of age.
Territorial disputes between female tigers are less common than between males. Young female tigers who have just left their mothers usually go on to find completely unoccupied territories. However, young males may go to an already-occupied territory to challenge the current male owner. If a tiger is observed fighting often, it is probably a male.
Determining whether a wild tiger is male or female can be challenging, but with careful observation, scientists can often solve the mystery, even if they must keep their distance.