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06-19-2020, 09:37 AM( This post was last modified: 06-19-2020, 09:39 AM by Ashutosh )
An 8 year old elephant died in Dechauri range of Ramnagar forest adjoining Corbett Tiger Reserve. The cause of death is most likely an attack by tiger/tigers as they were injury marks on it’s trunk and hind quarters. Most likely reason for death being it bled out.
(04-17-2020, 06:54 AM)GuateGojira Wrote: The Prey of the tiger in the Indian subcontinent:
As you know, I like to make comparative images that not only shows the relative size of the species with a human, but also between other species and most of all, the real measurements of the animal. I focused in India, as I love its fauna, and I made several comparative images since 2015. Recently, about 2018 and 2019 I tried to make new set of comparative images updating the information but I lost all my information. However until this year I reconstructed much of my database and I also have new information about several species. The results are the new large images that I made where I described the full set of subspecies/populations of lions and tigers with real measurements, no estimations like many popular books.
Following this idea, I made the first comparative image of the main prey species of the tiger in the Indian subcontinent. I read several studies and books but very few have long terms studies, most of the dietary studies are just about 1 or maybe 2 years at the most. I decided to focus in 5 parks in India and Nepal: Kanha, Chitwan, Nagarahole, Ranthambore and Panna. From those areas, several experts made long term studies, Kanha is special because even when the study was just a little over 1 year, it is the first true scientific study and its value is incredible and can't be ignored. People like Schaller, Sunquist, Seindensticker, Karanth, Thapar and Chundawat, amoung others, make great investigations and observations in the field, providing the modern profile of the real tiger in the wild. Following the studies in this great area and also those from McDougal and Sankhala, I found that the main prey species in India are several deer species and wild boar and also, when present gaur and nilgai. Also the langur is present in a relativelly important percentage, although is not predated in relation of its abundance. Other species is the porcupine of India, but although is somewhat present in some samples, it is not important as a prey and a recent study of Kumar (2016) suggest that predation in this species is more like an habit for survival than a choice per se. At the end, nine species were choosed as the main prey of the tiger in the Indian subcontinent: Chital, Sambar, Wild boar, Hog deer, Muntjac, Gaur, Barasingha, Nilgai and Langur. There are many other species, including Dhole, but as they importance is minimum, where not included.
Now, here is the comparative image with the 9 main species, while the first three are the most important overall, the others were placed in that form for space issues:
*This image is copyright of its original author
The measurements that you see are real ones, not estimations, except for the Barasingha and Nilgai "head-body" length, as there is no information and I used the figures of Blandford and Brander which we can guess came from real animals. Also, as you can see, I made some changes in the information, updating or expanding the sample and focusing in Indian specimens, so the body measurements of the Chital from Hawaii and those of the Nilgai from Texas (USA) were excluded.
Now, here are a few remarks about the species:
1 - Chital: The most important prey item in India and Nepal, all the studies conclude that. The measurements of the specimesn from Hawaii where excluded and I used only those from India and Nepal. However I leave the weights so we can compare those from Hawaii and those from the Indian subcontinent. It is interesing to mention that according with the study of Dr Chundawat in his book og 2018, the overpopulation of chitals is not good for other species, he explained that when there is a large population of chitals, tigers predate on them thanks to its great availability and big density, however when the prey population grow because of that, they start to select the bigger preys like sambar or barasingha, however while the chital population can recover incredibly fast, those of sambar and barasingha can't so he explained that tiger conservation and its habitat can't focus only in the recorver of the chital, but they must take in count the other larger species, specially because of the fact that tigers select more the bigger species independently of they density, which means that tigers will kill chital based in the availability but if they can they will activelly search for the biggest prey available.
2 - Sambar: The ideal prey for the tiger, and is predated independently of its density. This is the second prey item in the entire area. I joined the body measurements of the specimens of India and Nepal as the diference between them is almost inexistent. However I decided to separate the weights as based in the records it seems that the Sambar from Nepal are the heaviest ones with a record for a male of 380 kg. It is important to mention that the body measurements from the Sambars in India were made "between pegs" and those from Nepal probably "along the back" but the diference is, again, minimum, so probably they followed a straight line on the specimens and did not presed the tape.
3 - Wild boar: The measuremesnt and the weights are the same, no change in the information, I just changed the image and reduced the size as the other was somewhat exagerated. It is interesting that while the wild boar is an important prey species for tigers, they are suceptibled to deseases and they die in great numbers, that will explain why the early samples from Kanha and Chitwan showed lower predilection for this species. This is also reflected in the Russian Far East and specially in the Caspian region. It seems that tigers "love" boars.
4 - Hanuman langur: This is more like a "chocolate" for tigers, they are small and will be consumed in just one sit in a couple of hours. There are represented with a good percentage in the samples of scats but as they are way more available than the amount consumed, it seems that is not a main prey item in the sence that tigers can't survive with just langurs. They are important in number, but are not preferable prey.
5 - Muntjac: This small species is selected by tigers in any place that they live. Again, like the langur, they are important because of numbers, but tigers can't live and reproduce only with this species.
6 - Gaur: By far, the largest prey that a tiger can take single-handle with the biggest hunted bulls been up to 1,000 kg (Karanth, 2013). The gaur is predate by tigers wherever they live, but it depends also of the density. For example in Chitwan NP, Nepal, there was no predation recorded and Sunquist (1981) said that the size of the gaur make it invulnerable, but latter in he and his wife fiona in the chapter 10 "Ecology constraints on Predation by Large Felids" of the book "Carnivore Behavio, Ecology and Evolution" of 1989 they said that the lack of predatio was because the density of gaur was very few during the study period. The same happen in Pech where two studies showed diferent results, the old one had 0 predation on gaur while the next one some years latter showed predation of tiger over gaur. Gaur is perfect prey for tigers but is killed in accordance with its relative abundance in the prey community. In the gaur weight sample, I excluded a figure of 770 kg from Sunquist & Sunqusit (2002; about the case of the tiger that dragged the gaur carcass) as it is not a real figure (Perry, 1965) and I included a weight reported by Brander (1927). The measurements were all taken "between pegs".
7 - Hog deer: This is an important prey ittem for tigers in Chitwan NP and Nagarahole NP. It size is close to the average weight of the female chital deer and it is not as fast as the last one.
8 - Barasingha: This is the second largest deer in India, after the sambar, and a very important prey item for tigers, at least in the past. Barasingha is extirpated for most of India and Nepal and now there are only a few spots like Kanha and Kaziranga. However, if it were more samples probably it will be the forth most important prey item after chital, sambar and boar. Lack of data forced me to included two captive females in the weight section, so probably, like in the sambar, the females in the wild will be heavier than those in captivity.
9 - Nilgai: The last, but not the least, nilgai is certainly an important but unnusual prey item for tigers. Why? Well, tigers and nilgais do not share territories very often as this antelope, the largest of Asia, live in open and dry habitat (like the Asian lion) which is not tiger territory. However in two places, Ranthambore and Panna, the nilgai is a very important prey item and because of its size, it could be one of the main prey items if the territorios overlaped more. Thapar observed a very interesting interactino of several tigers over a nilgai kill in Ranthambore.
Now, normally people in forums quote the table of prey items in Sunquist et al. (1999):
*This image is copyright of its original author
However, when I check the original data in the original documents, the information did not match, so I prefer to use the original sources, like most of the books that I saw, so here are the original sources for the parks selected for this study:
* Kanha - Schaller (1967):
*This image is copyright of its original author
* Chitwan - Sunquist (1981) - first study in the 1970's:
*This image is copyright of its original author
* Chitwan - Bhandari et al. (2017) - new study from 2014:
*This image is copyright of its original author
* Nagarahole - Karanth & Sunquist (1995):
*This image is copyright of its original author
* Ranthambore - Bagchi et al. (2003), also Thapar's observations in several decades:
*This image is copyright of its original author
* Panna - Chundawat (2018):
*This image is copyright of its original author
So this is the information about the most important prey species for the tiger in the Indian subcontinent, save it for future references and you can use the image for future comparisons.
