ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

[peter]

THE SIZE OF BIG CATS

1 - How to express size 

There are many ways to describe the size of big cats. Bengt Berg ('Tiger und Mensch', Berlin, 1934 - I have the Dutch translation published in 1943) thought size should be expressed in skull dimensions and weight, but in the days of the British Raj the size of big cats in India was expressed in feet and inches.

In the early days, hunters produced tigers of 11, 12 and even 13 feet at regular intervals. No questions were ever asked. When hunting became more popular and hunters reported on the size of the big cat(s) they had shot in magazins, measurements were taken more seriously and debates erupted on the methods used to measure a big cat. 

In those days, two methods were used. Most hunters measured big cats 'over curves'. In order to measure a big cat in this way, a flexible tape was used. The tape was pressed to the body and followed all curves of the body between the tip of the nose and the end of the tail. Others measured big cats 'between pegs'. In order to measure a big cat in this way, markers were placed at the tip of the nose and the tip of the tail. After the markers had been placed, the cat was removed and the distance between both markers was measured in a straight line with a steel tape. 

The first method, because the curves of the body were included in the measurement, produced more impressive results than the second method. Most hunters measured big cats in this way. The problem with this method was it produced different results when a cat was measured by different people. The differences often were considerable. For this reason, the method was considered unreliable.    

The second method was often used by Forest Officers, biologists and zoologists. They preferred this method, because the result, in their opinion, reflected the actual length of a big cat. There was another advantage. If a big cat was measured in this way by different people, the differences usually were well within an inch.

In spite of the advantages of this method, the debate on methods never was concluded. I could post a few scans of the debates I read, but I opted for Sterndale's summary (1888). The reason is he needed little room to explain why a measurement taken over curves was unreliable. Another reason is he offered an alternative:  

*This image is copyright of its original author

           

2 - The result of the debate on methods

The outcome of the debate on methods was unsatisfactory in that hunters never adopted a uniform method. There were, however, some positive effects. One was that the second method ('between pegs'), considered more reliable, was more often used. Two was that those who continued to measure big cats 'over curves' paid more attention to accuracy. As a direct result, the number of 11-footers quickly dropped. And the 12-footers disappeared completely. In India, that is.

The method selected to measure big cats not only was a result of the debate on methods. Local habits also were important. In northern India and Nepal, hunters continued to measure tigers 'over curves'. Measuring usually took a lot of time, as it was considered very important. Most hunters who measured tigers 'over curves' in northern India used steel tapes after the debate on methods. They also often measured tigers 'between pegs'. Most hunters agreed the difference between both methods were 2-5 inches in adult tigers (both sexes).

In north-east India, hunters also continued to measure big cats 'over curves'. The habit never changed, although the Maharajah of Cooch Behar adopted the second method for a while. As he also continued to measure big cats 'over curves', we know the average difference between both methods in that part of India was 5,45 inches in adult male tigers. In one large male, the difference was 7 inches. 

In Central India, tigers had always been measured 'between pegs'. When a Forest Officer or hunter used to measure big cats 'over curves' in, say, northern India moved to the Central Provinces, he had to adopt the second method. And the other way round. In southern India, there was no preference, although I noticed most hunters measured big cats 'between pegs'. The situation described above didn't really change after World War Two. 
 
3 - After Independence

When it became clear that tigers in India had all but disappeared in the late sixties of the last century, hunting was banned and tigers were protected. It was a very close call for some decades, but tigers eventually recovered to an extent. 

Hunting now is a thing of the past. Most tigers live in reserves and they do quite well. In order to find out more about their habits and needs, it was decided to study tigers in different parts of India and Nepal. In some Indian reserves, tigers were darted, measured and weighed by Indian biologists. In Nepal, American biologists darted, measured and weighed tigers. 

Some of us read the articles and books they produced. Those interested in size and weight noticed a few problems. On animal forums, debates erupted. They often compared to the debates a century ago described above. When the debates didn't produce the results that were expected, biologists were contacted. It was then that those with questions discovered they would not be answered in a satisfactory way. The main reason was confusion about the methods used. Another was inadequate scales and different people publishing different things about the same tiger. 

4 - Methods today - Nepal

The tigers darted, measured and weighed in Nepal were large animals. The tiger who got most attention was the Sauraha tiger. He was darted, measured and weighed more than once and kept on growing when he was an adult. The final result was 10.2 and 261 kg. Or thereabout.

Thereabout? He was measured and weighed by a biologist, wasn't he? Well, yes and no. I mean, he was measured, but I don't know who measured the tiger. I'm also not sure about the weight, as he bottomed a 500-pound scale when he was weighed the first time. Some years later, when he was darted again, he had grown in both length and bulk. He then apparently bottomed a 600-pound scale. The weight often used (261 kg.) apparently was a result of a regression equation based on chest girth.   

As for the measurement. Sunquist wrote he was 10.2. That's true, another who was there later wrote: 10.2 'over curves':

*This image is copyright of its original author

          
       
This scan says the tiger wasn't measured by Sunquist, but someone else. He apparently measured the tiger 'over curves' and not 'between pegs'. Not true, Sunquist said when he was contacted. The tiger was measured in a straight line. But he added a few remarks on curves and straight lines that left room for some doubt. WaveRiders, correctly, pointed to the problems described.

After everything I read, I concluded the tiger was a large male. A bit longer than the captive Amur tiger I measured, but more robust. My guess was he really was 10.2 in a straight line and very close to or just over 600 pounds just before he, accidentally, drowned, but I have to admit I'm not sure. The reason is the confusion described above. I will use the tiger for the table, but it is a fact they should have delivered a bit more.

5 - Methods today - India

Ullas Karanth is one of the leading tiger authorities today. His dedication and expertise are beyond doubt and I think he's one of the men who made a real difference. Some years ago, I bought a book he wrote ('Tigers', London, 2001). I know the book wasn't intended for his peers, but the information on size is quite confusing: 

*This image is copyright of its original author

*This image is copyright of its original author

    

It is about the parts in green and red. After referring to the old debates on methods, 11-inch tapes and ridiculing all records of large tigers in the past, he introduced Pocock as the one who made a difference. But Pocock, in his 1929-article on tigers, was as inaccurate as they come. So much so, he was lectured in a letter published in the JBNHS (...). It is true he quickly learned, but I wouldn't consider him an authority on methods, size and big cats. The one who lectured him was, but he, of course, was dismissed because he was a hunter.

After discussing Pocock, Ullas Karanth said most zoologists now measure tigers 'over curves'. This method, however, is unreliable. A big cat should be measured 'between pegs', as this reflects the actual length of the animal. Ullas Karanth, therefore, is turning the world upside down. Just imagine what would happen if we started measuring humans 'over curves'. A man of 5.10 'over curves' in India would turn out to be 5.5 'between pegs' in, say, Australia. You're not the one in your passport, they would say.   

Then the remark on Heptner & Sludskij and the 13-footers in Russia. The table he refers to is flawed and I don't mean meaby. It has so many mistakes, I wouldn't know where to start. Their book is one of the best I read, but they had about as much knowledge of methods as many of their peers.   
       
So what to make of his remark that tigers in Russia and India are similar in size? I really wouldn't know. It would, regarding length, depend on the method used and my guess is tigers in Russia were measured 'between pegs', whereas those in India, judging from the description Ullas Karanth gave (see above), were measured 'over curves'. But Guate, who apparently contacted Ullas Karanth, said he measured the tigers he darted 'between pegs'. In weight, they most certainly were not 'similar'. Indian tigers, even after adjustment later on, were and still are heavier. Same for Nepal tigers.

6 - Methods today - Russia

The WCS-table on the dimensions of today's wild Amur tigers (Kerley et al) is reliable in that they, according to the information in the Appendix, apparently were measured 'between pegs":

*This image is copyright of its original author

The result of their table, in spite of the good start, nevertheless is unreliable. The reason is they didn't distinguish between adoslescents (2-3), young adults (4-6) and adults (7 years and over). They just moved all tigers in one table. Then conclusions were drawn. Most of these, for the reason mentioned, are incorrect. Adult male Amur tigers of 7 years and over are not 294 cm. in total length and 176 kg. in weight.

When I did a calculation based on skull measurements a long time ago, I got the same result regarding length: 9.9 for adult males. I could have been wrong. If so, adult male Amur tigers of 7 years and over would not be shorter, but longer. As for weight. Many mature males have not been measured and weighed. Those I saw (videos and photographs) were large and quite robust animals. I'm not saying today's wild male Amur tigers are well over 430 pounds, but I think they are much closer to the historic average than many assume.   

7 - Conclusions

WaveRiders, responding to a post that had quite a few critical remarks directed at the scientific community, concluded most remarks were unfounded, if not a result of plain bias. The facts, however, point towards something very different.

The information posted, only a fraction of what I have regarding misinformation, proves without a shadow of doubt that some biologists and zoologists do not seem that informed on the debates on methods I referred to. It's also quite clear some of them do not know how to measure a big cat in the correct way. And if they did, they managed to pollute the tables by not distinguishing between age groups. Those who avoided these problems often struggled with an 'overused' database.

The result of all assessments on size, to put it mildly, is a mixed bag, if not complete confusion. In spite of all that, some biologists do not mind dismissingh records of the past because rumour has it one or two shikari's might have used 11-inch tapes to please the hunters who employed them. I agree cheating can never be excluded, but even if it happened one can't use it to dismiss all old records out of hand. This, I think, would compare to 'seen one tree, seen 'm all'. A bit over the top, I concluded.        

Today's biologists are not that interested in size and methods. Although they often complain about the limited database, not one, apart from J.H. Mazak, even attempted to change the situation. Many skulls have not been measured and they probably never will be. The only attempt to evaluate historic records I know of (Slaught et al) has many flaws and inconsistencies. All in all, the situation is far from satisfactory. The lack of data probably has a profound effect on knowledge. At times, statements on size and historic records are close to misinformation. 

8 - But

Today's biologists no doubt give it everything they have. It is about protecting a species walking the edge and there's no question they succeeded. Quite an achievement. I was thinking of a fitting reward. My guess is Mr. Nobel would have been impressed by Jackson, Rabinowitz, Ullas Karanth, Miquelle, Goodrich and many, many others. We also would have to include those who wrote about the plight of tigers in the days many thought of hunting. Arseniev, Kaplanov, Yudakov, Nikolaev, Pikunov, Heptner, Sludskij, but I wouldn't want to forget about Corbett.  

There's no question that energy invested in expanding the database on things that do not really matter, like dimensions, isn't going to help wild tigers. Expanding knowledge on habits, more and larger reserves, corridors, training, education, fighting poachers and informing those involved in decisions is going to make a difference. They, therefore, made the correct decision. Thanks to them, we still have wild tigers.

I can, to wind it up, understand the attitude towards 12-footers. Everyone interested in big cats knows that only very few wild tigers exceed 10 feet when measured 'between pegs'. They also know the size of tigers probably didn't change dramatically in a few centuries only, meaning 10-footers in the 18th century, in relatives, probably were as scarce as they are today. 

There is, in spite of that, no need to dismiss all records about very large animals in the days they still inhabited most of Asia out of hand, just because those involved in dismissing didn't measure tigers of exceptional size themselves. Those who reported on exceptional individuals a long time ago often were as experienced as they come and they too didn't believe in fairy tales. They shot very large individuals, because they lived in a different time and because they knew how to get to these giants. Ony those with a lot of experience and knowledge were able to do that. I take them very seriously.

We also have to remember that individual variation in big cats is significant. Some captive male tigers are very close to 11 feet in a straight line. I saw at least two. And then there is George Jankowski. He hunted all his life and I take him seriously. Jankowski was very distrustful of reports on giant tigers in Russia. In spite of that, he measured males well exceeding 12 feet 'over curves' more than once. And what about his sons and their giant tiger shot in Manchuria in 1943? He was 11.6 'over curves'. The photograph they produced showed a very large animal, but he wasn't even considered by Slaught. Dismissed out of hand, I concluded. Let's proceed to Baikov. He too isn't taken seriously. Slaught, for some reason, didn't buy his reports on 13-footers exceeding 700 pounds, but the 560-pound male shot near the Korean border still tops the list of accepted records. That tiger, although long, wasn't even close to some of the tigers I saw. I could continue for some time, but I'll leave it at that. The message is many assessments of reports on large tigers, for good reasons, are far from convincing.  

We could approach the problem on size in another way. A century and a half ago, large animals were seen and shot in the Sunderbans every now and then. Sunderban tigers are directly related to tigers in Central India. Central India tigers still are large animals. Sunderban tigers, however, are now smaller than anywhere else (...). If isolation, stress and a depleted prey base are able to tranform large tigers into miniature tigers in a century only, then why dismiss reports of naturalists and hunters on extra-large tigers out of hand? Tigers living in good conditions in the days Asia still had 100.000 tigers? The question, therefore, is if wild big cats can increase or decrease in size in a relatively short period of time. The answer to the question is yes. For proof, go to the Sunderbans first. If you see a male tiger exceeding 270 pounds, you would be the first. Than visit Central India, where adult males often exceed 500 in their prime. What more do you need to get to the correct conclusion? Reply