Tiger Demographic

[Dr Panthera]

(04-10-2016, 05:23 AM)Shardul Wrote: I assume this is directed at me, since I was the one who questioned your claim of <1000 breeding adults in India. Do you know of any scientific study conducted in this regard in India or are you just extrapolating Chitwan's data to all of India? 

In the documentary "Tigers of the Emerald forest" based in Panna National park in Northern India, narrated by Dr. Raghu Chundawat, the tigress Julie mated with both the territorial male Madla and a transient male Broken tooth, who sneaked upon her when Madla was on a patrol of his vast territory. Dr. Chundawat specifically mentioned that female tigresses often wander far and mate with several males when in heat. This behaviour was again observed in another documentary shot in Ranthambhore, where the tigress T-17 mated with male T-28 and then went out of her territory and mated again with the male T-25. No one knows who the father of her litter was, since she mated with both males. Another instance was observed in Bandhavgarh where the Bamera male was seen watching the old male Bokha mating with one of his tigresses. So we have recorded instances where tigresses mate with both territorial and transient males. So we cannot assume that transient males are not breeding males. Also, tigers can breed right till their old age. B2 fathered cubs even when he was more than 12 years old, so did charger. The recently deceased Baghin Nala female of Pench had produced her last litter at the age of 12.

Now, the study you quoted says (taking the mean value), percentage of breeding adults is about 42%, but that is when counting small cubs, which make up 30% according to that study. India's census does not count that 30% small cubs. (It  only counts the 70% population of adults and large cubs >1.5 years), and 42 is 60% of 70 . Considering some transient males also breed, that percentage would be even higher. So that would peg the number of breeding adults in India's case at >60% of 2200 which comes to >1320. While you said it was <1000. That was my whole point.

No not really and I apologize if I sounded like that, in a nut shell whether the results of Chitwan ( and possibly all the Terai landscape) and the Sunderbans ( from M.Khan) or any tiger stronghold the pattern is the same: Tigers have cubs when the conditions are good and in the best habitat every breeding female is likely to have 2-4 cubs with her, so in good habitats the percentage of cubs and sub-adults will outnumber adults whereas in populations where tigers are decreasing in numbers and under a lot of pressure the majority will be adults. Some habitat in India are great others not so much so the breeding animals there could be as low as 800 and as high as 1500.
that is not to say that a small isolated populations of tigers in India and elsewhere could be almost 100% adult...for sure but these populations will go extinct in less than ten tiger generations ( 35 years ) if the current trends continue.
Similar trends are noticed in lions and leopards, and all mammals who have multiple young per litter, healthy populations breed successfully and have plenty of surviving cubs and sub-adults inflating their percentage in the population.
Mating of transient animals is sporadic and occasional and can not be considered regular tiger behavior certainly where territorial male numbers are optimal but I agree that it happens more than previously expected.
We need to intensify efforts for conserving tigers especially in tiger conservation units of first grade since they are the future of this amazing predator. Reply