Tigers, like all the members of the Felidae family (except for the lion and cheetah), are solitary and territorial. However, there is some plasticity in the behavior of this animal, depending of many factors like prey density, habitat type and even "personal" behavior. Here I am going to share a little summary of the results of scientific studies regarding the social behavior of tigers in the Indian Subcontinent and Russia. The next picture was the first image of a male tiger with the female and the cubs together, courtesy of the great Valmik Thapar.

 

George Schaller (in the picture) was the first one that made a scientific study about tigers and its prey in the Indian subcontinent. His pioneer work is still the guide for many modern studies on tigers. He was only about one year in Kanha and he found that male tigers were territorials but that females were not, so male had "territories" while females only had "home ranges". Females shared its territory with other females except for the core areas of the home ranges. He also found that tigers were tolerant with its cubs and even shared a kill with his family (female and his cubs), but for some reason this observations were ignored for long time. So, tigers in Kanha had this social structure until the 80's, as Sunquist (1981) quote Panwar (1979) saying that after the recovery of Kanha and the new higher prey level, the tigresses began to be territorial, avoiding any contact with other females. This is the behavior found in the Nepal tigresses, which suggested that a good prey base allow tigers to be more independent and became more territorial.

The Nepal Tiger project found that tigers in Nepal are highly territorial but the females do share they home ranges with her daughters, although sometimes there are conflicts. However, it took time to found this information. At the beginning Dr Charles McDougal (1977) believed that there was some degree of overlap between the females and that they were not territorial, however at the light of the new evidence of the radio-collared tigers he wrote an Postscript in page 165 of his book where he accepted that the home ranges of the tigresses were in fact “Territories” that are defended from other females. Dr Mel Sunquist (in the picture), in his document of 1981, using radio-collared tigers, found that males are territorial and that females also have delimited territories but his sample was small. Latter Dr Dave Smith and others (1987 - 1993) found that the conclusions of Dr Sunquist were correct: male tigers are highly territorial and only allow the presence of they own sons for a short time, but nor from other males which they will expel from they territories; female tigers are also territorial but may share here territory with her daughters, although sometimes the daughters may displace they own mothers from the territory, like the case of female T-01. Females form "family clusters" like lionesses prides but each female in her own territory, even Sunquist believed that if the habitat where the same, tigers have the entire capacity to live like in groups like lions. They also found evidence of conflicts between tigers, but while this were minimum at the beginning (Sunquist, 1981) they became more serious, especially after the death of the "king" tiger M-105 (Sauraha male), and that showed that the presence of a strong male is very important for the stability of the area, especially for the females in order to produce cubs (Seindensticker, 1996). Also the larger population of Nepal tigers and the short space increased the conflicts and by the 90’s started the cases of Man-eater tigers, something that in the time of Dr Sunquist was not almost unthinkable. Overall, Nepal is the best example of the "normal" tiger ecology and behavior, with a good prey base and some of the smallest territories on record. 

In Ranthambore, the habitat situation was different, it is more open, and is possible to follow the tigers at eye sight, something that is not possible with tigers in Nepal as the habitat is too close (Sunquist, pers. comm.). Valmik Thapar (in the picture) together with many other observers provide us the only long terms visual study that may compete with the Nepal Tiger Project, not only for its time frame, but also for the information obtained. In the series of books from Mr Thapar he was able to describe the ecology of the tigers and is very interesting. Thapar was the first one to describe the role of the "father" in the tiger society in his book "The Secret Life of Tigers" and he found that males DO protect they cubs and take care of them if the female is not present, he hypothesize that males protect its territory not only to preserve its females but also to protect its cubs, and the time showed how correct he is. He also saw males sharing its kills with them families, even allowing the females and cubs to eat before them, something that is not recorded even in the social male lion! In the book "Tiger: portrait of a predator" he described a reunion of nine tigers over a prey (a large nilgai) and all the tigers ate from the kill in order, with no conflict and all the feeding was regulated by the older female, the one that made the kill. He found that all the animals were related except for one, and this case was also presented in the book "Tiger: the ultimate guide". However, I found that in the book "The secret life of Tigers" Thapar do shows that that "unknown" tiger was in fact, a relative of the group, so what he saw in that moment was a "pride" behavior at a kill of related tigers, but the tigers showed a more "advance" for of sharing the kill, with no fights or conflicts (evidence of the use of they larger brains?). At the end, he got to the same conclusions that the tigers of Nepal: Male and female tigers are territorials, but males may share its territory with them sons and females do divide her territory with her daughters, however there are conflicts and severe fights may happen. New observations from modern naturalists showed male tigers sharing kills and also taking care of the cubs when the female is dead, but is sad that all this observations are scattered and not compiled in books like Mr Thapar done.

The Panna studies are the first one done in the dry forests of central India. There Dr Ragu Chundawat (in the picture) found that the tigers were also territorial like in Nepal, but the females were not entirely and there was a great overlap between them except for a core area, just like the case of Kanha in the time of Schaller. This may be because of the prey base, which is lower than in Chitwan and Ranthambore, but also is important to show that the radio-collared tigresses were a mother and her daughters, so that may explain why the females shared some areas. Males are territorial and do not allowed any other male, but as the territory is too large (about 250 square Km) some areas can't be watched all the time and he found some transient males in the areas, that avoided the large territorial males. However conflict raised when there are females in heat and the males following them fight each other. The large male M-125 (Madla male) lost an eye in one of those conflicts. His studies were incomplete because all the tigers of Panna started to disappear and when Dr Chundawat requested for assistance to investigate the case, the park rangers ignored him and even "kick out" him from the park, the result was that Panna, like Sariska, lost all its tigers. However, with the reintroduction of tiger in Panna, Sarkar et al. (2016) found that the "new" tigers "behaved almost exactly the same way as that of native populations, offering support for reintroduction strategies."

 

In Nagarahole, Dr Ullas Karanth (in the picture) made a study with radio-collared tigers but his results were incredible. While the female was territorial, the males were not. In fact, in his book "The Way of the Tiger" Dr Karanth presented this conclusion, together with some form other studies, but please take in count that his data about Panna and the Russian Far East needs to be updated:

 

It seems that the tigers in Nagarahole do not show exactly the same behavior than the Chitwan tigers, but we must note that he don't knew if the males T-03 and T-04 were relatives of not, which may be posible based in the relations between male tigers in Chitwan and Ranthambore. Dr Karanth continues his studies so more information may be available in the future.

 

In the Russian Far East, the tigers should show a different behavior, especially because of the difference of habitat and prey density. The first Russian studies from Baikov do not focused too much in tiger territoriality and Heptner & Sludskii (1992) which compile all the available information in Russian literature, shows that tiger home range did overlap extensively. However, the new studies made by The Siberian Tiger Project show something different. It seems that despite the habitat difference and low prey density, male tigers are still territorial and although the overlap exists, this is still minimum. The same case happen with females, with some overlap but this is also minimum and tigers do not migrate to follow prey. Dr Dave Miquelle and Dr John Goodrich (in the picture) made an excellent work in the Russian Far East and shows that tigers in the area, despite the huge differences in habitat, do behave about the same than those in the Indian Subcontinent (Goodrich et al., 2010). Check the conclutions in Sunquist (2010):

Now check this table, which corrorborate Dr Sunqusit conclusion, this is from (Goodrich et al., 2010):

We can see that all tigers are territorial in the Indian Subcontinent and the Russian Far East. The case of Kanha was already explained and now the females are territorial too. The case of Sumatra must be taken with caution as is very important to know if the tigers in the camera traps are related or not.

 

Also check this famous picture:

It seems that male Amur tigers shows the same protective/sharing behavior of the tigers in the Indian subcontinent. Trough time, more information will clarify the situation.

With this information, we can see that tigers are solitary but not antisocial. They are territorial animals that protect its habitat but that can be flexible if the habitat requires it. Tigers are able to congregate in groups in exceptional situations, but normally prefer to be solitary as is more economic to take care of yourself in an habitat that is too close to coordinate an attack and where large preys live at low densities. Females priority is a good habitat with enough prey density to feed her and her cubs, they will share the habitat with her daughters like a big scattered "pride" and may be together in exceptional cases. Males priority are large territories with enough females to mate, they may tolerate its male offspring as long as they don't attempt to mate with its females and certainly both, males and females, will not tolerate estrange tigers, because they may kill the cubs and take over the territory if they can. Fights between tigers are not the norm but do happen and are lethal, but they prefer to use they specialized method of socializing at distance. Even the lack of aggression when they are together and feeding in family may be evidence of the high degree of cephalization of this species, in comparison with the other Panthera members (Yamaguchi et al., 2009).

There is more information in the subject, but this summary present the main conclusions of the respective studies.

Hope this helps, Greetings and cheers.