Till couple of years back it was difficult to study tigers in their natural environment, but with the establishment of protected reserves it has become much easier to know about their life style, daily routine and social activities. Females reach sexual maturity around 3 to 4 years of age and males mature at about 4 to 5 years. In tropical climates, females may come into oestrus throughout the year, though mating seems to be more frequent during the coolest months (November to April). In temperate regions, she enters oestrus and mate only during the winter months.
The courtship and ultimately mating, starts with tigress coming into oestrus (the time when a female is receptive and capable of conceiving young), which she does every three to nine weeks, and her receptivity lasts three to six days. Tigers usually begin their courtship by circling each other and vocalizing. Female advertises her readiness to mate. During this time she becomes restless, very mobile and vocal, leaving her scent by spray-marking, scratching trees and rubbing herself on bushes. All this is done to attract males. Sometimes all this attracts single male, but there are occasions when more than one male are attracted and in this situation a vicious fight can break out over the female. One such encounter was recorded by P. Hanley in his book “Tigers Trails in Assam” (1961). He found tigress vocalising with great regularity. This soon attracted a male who cautiously started his approach, in the mean while another male appeared on the scene and attacked the first male. The fight was so vicious that one of them succeeded in tearing the other’s neck open with a gash of its massive claw. The wounded soon left the scene bleeding and limping badly. According to Hanley he observed a third male watching the fight from behind a bush. Before a victor could reach the tigress the third male sprang towards him. The exhausted victor was no match for the new entrant and was easily chased away. Soon the tigress and the third male bounded away into the forest. While the fight was on the tigress sat quietly throughout watching the aggressive conflict over her.
The normal time that both male and female spend together is between three and seven days, when the tigress is at her most receptive. During this period copulation takes place many times even in a single day. According to a book “Tiger: Portrait of a Predator” (1986), by Valmik Thapar, the photographer Fateh Singh Rathore, who clicked photos for the book in Ranthambhore Reserve “watched eight copulation in 88 minutes.” Sometimes the pairing period can be stretched to a couple of weeks. Finally when the male mounts the female the final act of copulation begins. According to Desmond Morris’s book “Animalwatching: A Field Guide to Animal Behaviour” (1990) “The mating behaviour of members of cat family is a painful process for the female. The male’s penis is barbed and its withdrawal hurts the female, who frequently twists round to attack the dismounting male. The pain is necessary for feline mating because it is this shock to the female’s system that induces her ovulation and permits fertilisation.” Several days of mating interactions may be required to stimulate ovulation and guarantee fertilization of the egg. Both male and female tigers may have several mates over their lifetime.
Morris adds further, “….many male mammals can be seen to grab their mates by the scruff of the neck when mating. This neck-biting looks aggressive and even brutal, but it is not. In fact, it is a small behavioural trick played by the males on their females, enabling them to mount without too much difficulty. The neck bite acts as a pacifier and immobiliser. To find the reason for this, it is only necessary to look back what happens to young mammals when they are being transported by their mother. She picks them up by the scruff of their necks, holding them firmly but gently in her jaws. Their reaction to this is to lie immobile and to allow themselves to be transported without struggling. This is important if they have to be quickly removed to a safer place. When the adult mammal grabs his female in his jaws, she reacts as were his offspring. Programmed in infancy to lie still and not struggle when her mother bites in this manner, she automatically responds in the same way to her mate. In this fashion infantile responses can be usefully exploited as a technique that ensures a smooth copulation.”
Thapar says, “In Ranthambhore, records show that mating occurs at all times of the year, with no definite or intense mating season.” This is definite that once the tigress has conceived she will not come into oestrus again for about two years. She spends this period with her young. There are exceptions to every rule. So is the case with tigers; if the tigress doesn’t conceive or her cubs are killed, she can again come into oestrus within three-four months. This is the reason that males usually kill cubs so they can mate with the female and pass on their genes to new generations by fathering their own cubs. Males associating with a tigress and her cubs have also been observed, but it is a rarity. In 1965 George Schaller saw a large male with a female and four cubs, first when they were four months old and again when they were about eleven months old. Billy Arjan Singh has written in his book “Tiger Tiger” that he observed a male tiger amicably sharing a kill with a female and three cubs.
Tigress a Perfect Mother
After mating male and female depart on their separate ways. There is no definite knowledge about the gestation period in the natural environment, but in captivity it has been observed that it lasts from 94 to 115 days. It is difficult to identify a pregnant tigress because they do not begin to show a bulge until the last 10 to 12 days of pregnancy. This is the time when female starts searching for a safe place, which may be a cave, a natural rock overhanging or thick bush with dense cover all around so that helpless cubs remain properly concealed away from the reach of predators. Besides becoming sure about the safety of the ‘delivery room’ she has in mind other important issues too, like availability of food and water in the vicinity.
According to zoo records the time taken in giving birth to a litter, which may have up to six-seven cubs, varies from an hour to 24 hours. Average litter has 3 to 4 cubs and they are born blind whose placenta and embryonic sacs are eaten by the mother soon after the birth. This besides giving her nourishment also ensures safety of the cubs. Had it not been consumed the decaying odour of placenta and embryonic sacs can invite predators to her den. To avoid potential predators reaching the cubs by getting the scent the mother may also eat her offspring’s faeces. The eyes take a week to fifteen days to open and interestingly, the ratio of the sexes at birth is one to one.
Tigers reproduce well if given a chance. An average female can rear some six to eight cubs over her 10-12 year lifespan. Young tigers stay with their mothers in a family group for up to two years, learning the skills of hunting before separating to take up their independence. Young males may travel far, living a solitary life before establishing their own territory, often by ousting older or injured males. On the other hand young females often stay close to their mother and in some cases even share parts of her territory.
Once the cubs are delivered this lethargic-looking animal, which otherwise spends 80 per cent of its time resting, sitting and dozing in a shady, but strategically-placed spot during the day and occasionally getting up to stretch, suddenly becomes highly caring and ruthlessly protective mother. The early days after the delivery are mostly spent with cubs protecting and suckling them. There are no credible records of how long the suckling continues in the wild, but zoo records show it continues for three-and-a-half to four months. Despite the mother’s total commitment, care and protection the death rate in the cubs is very high during this period. Sometimes even half of the litter perish before reaching the adolescence. Death normally catches up with those who are born late and are weak and are unable to survive the competition that goes on among the siblings for mother’s milk. Despite this mother does all she can to ensure their survival. She spends almost all her time licking and cleaning the cubs to promote better blood circulation and bowl movement.
The tigress is solely responsible for the protection and care of her young for the first few months. She leaves her young for only short periods of time to drink and hunt. She spends nearly 70% of the time nursing the cubs for the first few days following birth. This time reduces to about 30% by the time cubs are a month old. If she finds any intrusion into the area around her den suspicious or detrimental to her cubs’ security she instantly takes preventive steps. After searching out some alternative but secure place she immediately shifts her offspring. Holding each of them by their neck, one by one she carries them with utmost care to their new home.
Care and Development of Young
Cubs start following their mothers out of the den around two months of age. However, they do not participate in the hunt at this point. They wait in a safe place for their mother to bring food back to them. They begin consuming solid food when they are six to eight weeks old. The mother starts bringing them meat, but in a different way. After making a kill she eats up whatever she can and regurgitates it later before her young. This serves many purposes. Firstly, the mother herself gets something to eat to keep her going; secondly, the regurgitated meat is semi-digested, which does not put pressure on cubs’ comparatively weak digestive system. It also solves the problem of carrying food. As the cubs grow little older she starts bring them raw meat. There are instances where tigresses have been seen dragging carcasses up to two kilometers. As a devoted mother tigress opens up the kill for cubs, but rarely eats first.
Between the age of two and three months the cubs are allowed to make their first limited explorations around the den under the strict supervision of their mother. From three months onwards they probably venture a little farther each day. Tigress remains extremely alert and cautious and as she walks she keeps them closely bunched together around her.
At the age of four months they are about the size of a medium-sized dog and spend their day playing, pouncing and wrestling with siblings. They are weaned from their mothers by six months of age. However, they are still dependent on the prey their mother procures for them. Although they are hunting on their own yet, cubs begin to explore and roam their surroundings more freely. Males weigh about 90 to 105 pounds by six months of age and females are about 30 pounds lighter.
Beyond six months cubs start to roam around more freely and the tigress moves them greater distances familiarising with various landmarks. In the process they watch and observe prey and the way their mother stalks, kills and eats, explore water-holes and learn about the ways of jungle life. It is during this period she besides teaching them about the ways of hunting, also starts instilling discipline through occasional slaps and sharp growls. Not only that, it is through a complex series of sounds youngsters are trained to avoid dangers and to remain quiet when she is hunting. They begin to hunt with their mother and siblings between eight and ten months of age. This is the time when tigress’s prime concern becomes to teach the young the hunting techniques and how to protect themselves in the hostile environment of the jungle. It has been observed that while teaching the mother first injures the prey and then allows the cubs to take on. This perhaps is done to stop the prey from running away and also from harming the cubs. F.C. Hicks writes in his book “Forty Years Among the Wild Animals of India” (1910), “If cubs are present, the hind leg of the kill will frequently be found to be broken, the idea being to disable the animal and then to play with it alive for the edification of the cubs, while the nose, ears and eyes will invariably be found much gnawed and torn by the cubs.”
Cubs spend most of their time playing with their siblings and their mother around fifteen months of age. This helps the growing cats to develop useful life skills such as stalking, pouncing, swatting and climbing. A hierarchical order takes shape by the time cubs are sixteen-seventeen months old, with the most dominant sibling, most often a male, eating and consuming most resources first. This is the time when mother starts leaving the cubs alone more frequently. She would absent herself for few days and then return. This is how she forces them to start fending for themselves.
Young become independent from their mothers around seventeen to twenty-four months of age. Males travel further from their mother’s home range than females. Young males will continue to grow and develop muscle until they are about five years old. They have been observed spending their early independent years around the fringe areas of the forest transecting the ranges of one or more dominant males. But this movement outwards is not permanent, and soon, within a year or two, they begin to move inwards in an attempt to take over control of prime territory. This usually results in vicious fights.
World’s First: A hand-reared tigress gives birth in wild
A five year-old tigress, tagged T-4, has become the world’s first hand-reared tigress to give birth in the wild. She was brought up in captivity and later shifted to Panna Tiger Reserve (PTR) in Madhya Pradesh (India).
According to the PTR field director R S Murthy “This is for the first time in the world that a semi-wild tigress shifted to the wild has adjusted to new environs and begotten cubs. The tigress was born in May 2006 in the Kanha Tiger Reserve (Madhya Pradesh) and within days her mother died.”
T-4 was reared in an enclosure and fed by the Kanha staffers. The semi-wild tigress was carted out to Panna and released into the wild on March 27 last year. There were apprehensions about the tigress’ survival in the wild, given that she was reared in an enclosure. But, she took to the jungle easily. Here she met a translocated tiger, and mated.
She delivered two cubs, and one of them was spotted by a PTR official on December 15. T-4 and her two cubs have started moving out of their den since last week. (Times Of India — Feb 16, 2012)