There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
02-03-2015, 05:33 AM( This post was last modified: 02-03-2015, 05:39 AM by WaveRiders )
The estimate of 221 kg suggested by GuateGojira as average weight of Chitawan NP adult male tigers coming from the figure of 235 kg (and the one for adult females of 140 kg) provided in the study of Smith et al. (1983) can in my opinion be refined on the basis of the following consideration.
Sunquist (1981) provides average food intake of tigers (unsexed) in the first 24 hours after a kill as 14,0 kg. His study basically included 2 adult males, 5 adult females (1 died at day of capture) and 1 subadult male with number of observations different from animal to animal.
I propose to use the very much known Kleiber’s Law to estimate the specific adult male and female average food intakes in the first 24 hours after a kill from the overall biased average 14,0 kg figure for males and females in the first 24 hours.
Without going into the validity of this law, a topic much debated in biology with countless number of studies, Kleiber’s Law states that the metabolic rate of all organisms scales to the 0,75 power of the body mass.
To strengthen the reasonable validity of my assumption I highlight that Sunquist (1981) suggests males tend (obviously) to eat more then females and that he observed 2 males eat 56 kg and 57 kg of meat respectively in 3 days of undisturbed feeding (18,7 kg/day and 19,0 kg /day) while a female 41 kg (13,7 kg/day).
“Magically” the ratio 18,75 kg to 13,7 kg computed from Sunquist’s examples (I neglect the extreme case reported of a female eating 30 kg in 24 hours) is close to the ratio expected by two cospecific animals weighing 235 kg (adult male average body mass including stomach contents) and 140 kg (adult female average body mass including stomach contents) respectively if the metabolic rate and the consequent energy needs would exactly follow Kleiber’s Law.
With a few mathematical iterations to calculate ratios from empty stomach weights and not from total body masses and assuming the average food intake of the first 24 hours refers to all individuals captured and radiocollared (2 adult males. 1 subadult male, 3 adult females and 1 subadult / then adult female) I got the following.
Adult males : average body mass at empty stomach 217,3 kg (heaviest 241,9 kg again following Kleiber’s Law)
Average food intake in the first 24 hours 18,3 kg
Adult females : average body mass at empty stomach 128,1 kg (heaviest pregnant 150,5 kg / non-pregnant 140,2 kg adult female again following Kleiber’s Law)
Average food intake in the first 24 hours 11,9 kg
Please note that the heaviest weight of adult Female 101 measured at 164 kg occurred while she was pregnant and relatively close to give birth to a litter (approximately 4 weeks if I do recall well as I read the report a long time ago). Therefore this weight was not a natural weight for the animal (apart from the stomach contents issue).