Raja the Tiger less than 500 lbs?

[peter]

As to the average of wild male tigers referred to in this thread (about 160 kg.): the source was a peer-reviewed document and Yamaguchi was involved.

The average for tigers they found most probably was a result of adding averages of wild males of the remaining subspecies (P.t. altaica, P.t. tigris, P.t. corbetti, P.t. jacksoni and P.t. sumatrae) and dividing the result (177 + 200 + 165 + 140 + 120 = 802 kg.) by 5 (= 160,4 kg.). I don't know if they included P.t. virgata, P.t. amoyensis, P.t. sondaica and P.t. balica, but my guess is they didn't. If they would have, the result would have been roughly similar or a bit lower.  

One could argue the real averages are a bit higher (190 + 205 + 170 + 145 + 120 kg. for males respectively), but I don't think they were far away from the mark. Same for the average of wild male lions they computed. My guess is the average of all wild male tigers ranges between 160-168 kg. (closer to 160 kg.), whereas the average for wild male lions ranges between 170-175 kg. (closer to 170 kg.). At the level of species, therefore, lions are a bit heavier. The main reason is no small subspecies on islands. They also have longer skulls. Tigers, however, have more distinct subspecies. One of these, the Amur tiger, is the longest wild big cat today and wild male Indian tigers are the heaviest. The difference with male lions in south-central, south-west and south-east Africa, however, is limited. 

Three remarks. One is there are about 3 000 - 5 000 wild tigers left, as opposed to 25 000 - 30 000 wild lions. Two is most wild tigers live on smallish islands not connected to other, severely restricting gene flow. Three is many wild tigers face tough conditions. 

Let's take Amur tigers. Although an average wild male Amur tiger probably never exceeded 225 kg. in the recent past (one or two centuries ago), all in the know agree their prey base (due to habitat destruction and poaching) has been poor for a long time. This is apart from a population bottleneck just before World War Two (today's Amur tigers can be traced back to 10-15 wild females). If the tough conditions in which they live are added, tigers well below their potential at regular intervals can be expected and this is what they found about two decades ago.

Talking about potential. There's not much to choose between captive African lions and captive Indian tigers, but there's no question captive Amur tigers top the list in many departments and genes probably are involved in some way. Although I don't doubt they were a bit heavier in the past, I see no future for a male of, say, 600 pounds. Amur tigers are professional hunters who walk about 9-10 km. in deep snow in winter. In difficult terrain and every day, that is. It is not a heavyweight boxer made to sun on the beaches of the Caiman Islands. There's also no roomservice. Amur tigers need a large body to conserve heat, but they don't need 600 pounds. Those who also combine a large size with meat (Amur male brown bears) lose up to a third of their weight in hibernation. And if they skip sleep and start to wander, they'll starve to death more often than not. If you are 600 pounds and like meat, you got to be able to maintain that weight and my guess is it is next to impossible in winter. The Russian winter is no joke and it lasts for at least 6 months of the year.    

Reality says 400-450 pounds is about right for a large solitary carnivore in Russia, but I don't doubt some some male Amur tigers hit 500. The giant Sungari River male shot in 1943 probably reached 650 pounds, but he, at 11.6 'over curves', was exceptional. Furthermore, one has to remember he only got to that mark after finishing the large brown bear he had killed. If we deduct the bear, he would have been 550-600 pounds. No more than the giants shot by the old Jankowski about a century ago, that is. A tiger of 650 and even 700 pounds empty is possible, but not in wild Russia. He would only able to make a living in a region with many large herbivores, a lot of water, extensive sal forests, short distances and few humans.       

Those interested in big cats who joined a forum often focus on exceptional animals. Fine with me, but you got to remember a male of 400 pounds is a large animal by any standard. As to large animals. My guess is tigers just south of the Himalayas (Nepal and north-west India) could be the heaviest. This also was the conclusion of J.F. Brandt a century and a half ago (although he referred to tigers only). Brandt based his conclusion on books, but today we have biologists carrying notebooks, darts and 600-pound scales. Although there's no question some exceptional males top 600 pounds empty, not one local type ever got to an average of 500 pounds. Not in my computations, I mean.

There's one consolation. We might get there after all, but biologists would have to distinguish between immatures (2-3 years of age), young adults (4-6 years of age), mature animals (7-12) and old tigers (13 and over). My guess is it will take a very long time to get to a reliable database.

One more to finish with. I've read a lot about weights of wild Indian tigers in the last two decades. In many cases, I'm unable to distinguish between facts and rumours. And then there is the department of adjustment. It wasn't there in Sunquist's day. Ullas Karanth only heard about it after the facts and, in order to prevent problems, deducted 30 kg. of the males he weighed (...). A bit too convenient for me, meaning I have a few questions. However. I don't doubt adult males in south-west India and Nepal well exceed 200 kg. (440 pounds).

The only thing one can say for now is quite many male Indian tigers appear to be massive animals. I wasn't surprised to read that two males in Nepal bottomed a 600-pound scale, but my guess is an average adult male, depending on region, would range between 420-480 pounds empty (the Sunderbans and Naga Hills not included). Compared to a century ago (when the average for males in four regions ranged between 402-460 pounds), they seem to be a bit heavier, but the number of observations is very limited. I wouldn't mind reading a peer-reviewed document about size in the near future, but my guess is there are more important issues to address at the moment. Reply