Amur Tigers

[johnny rex]

@peter said here https://wildfact.com/forum/topic-on-the-...#pid180466 since I can't post on the thread, I will post in this thread instead.

"The average greatest total skull length of captive male Amur tigers (referring to the tables in post 2,579) is 357,5 mm (range 332,5-380,0/n=16), but my guess is V. Mazak, who wrote male Amur tigers average 367,10 mm in greatest total length ('Der Tiger', 1983, pp. 191), could be right. The only big cat exceeding this average is the Kruger lion. In 'Brain size of the lion (Panthera leo) and the tiger (P. tigris): implications for intrageneric phylogeny, intraspecific differences and the effects of captivity', 2009, Table 4.1), Yamaguchi, one of the four authors, says males average 380 mm (n=15), whereas Indian male tigers average 351 mm (n=37).     


The problem with most averages is they're based on smallish samples used time and again. I've visited many natural history museums and also saw a lot of skulls in private collections. In spite of that, it took me a long time to find even 10 skulls of captive adult male Amur tigers. Skulls of wild Amur tigers are even more elusive. You can find a few measurements of skulls of wild Amur tigers in V. Mazak's 'Notes on the Siberian long-haired tiger (Panthera tigris altaica, Temminck, 1844)', that was published in 1967 (pp. 554-559), in 'On the sexual dimorphism in the skull of the tiger (Panthera tigris)', J.H. Mazak, 2004 and in a few other books and publications, but that's it.

What is needed, is a book that has detailed information (including photographs) about skulls of wild and captive big cats. I'm not referring to a book that offers information at the level of averages only, but to a book in which every skull is discussed. It's the only way to find, and explain, the differences between species and subspecies. It's also the most effective way to describe the differences between male and female skulls and the effects of age and captivity.          

The question, regarding skulls of captive big cats, is if there is a difference between head length and greatest skull length. This is needed in order to get to guesstimates. The answer is we don't know. One thing we know is there is a lot of individual variation. A few examples. 

The greatest total skull length (GTL) of 'Amur' (Prague zoo), who died at age 11,5, is 371 mm. The head length of this tiger was 45 cm. The head length of his son 'Benjamin' was 42 cm. The greatest total skull length of this male, however, is 377 mm. The head length of the Duisburg zoo tiger was 50 cm. Can we use the info about 'Amur' and his son 'Benjamin' to get to a few deductions? I don't know. It's likely the skull of the Duisburg zoo tiger is over 400 mm in greatest total length, but this is an assumption only. 

We also don't know if there are differences in this respect (head length and greatest total skull length) between wild and captive big cats. We do know the longest skull V. Mazak ('Der Tiger', 1983, pp. 191-193) measured was 383 mm (CBL 342 mm/ZW 268 mm). The skull was from an old male from Heilongjiang (northeastern China). Another skull, measured by Baikov and also from that region, allegedly was 16 inches in total length (406,40 mm). V. Mazak (1983, pp 193-194) thought the photograph was real. He added skulls of this size have to be expected when tigers reach an exceptional size.   

And what about the skulls of the tigers shot over a century ago in Cooch Behar, the Duars and Assam by the Maharajah of Cooch Behar and his guests? Some of them ranged between 15 and 16 inches (381,0-406,4 mm). The answer, again, is we don't know. I do know there's usually a difference between a measurement taken by a hunter (or naturalist) and a measurement taken by a biologist or someone who measured a lot of big cat skulls. In a large skull, the difference can be as much as 6-7 mm (referring to my experience). My guess (referring to skulls of tigers shot in what used to be British India) is we'll never know. I do know hunters like memories. Most exceptional skull are in private collections and most owners avoid publicity. 

Are skulls of lions, as many think, really longer than skulls of large wild tigers in Russia, northeastern China, Nepal, northern India and, in particular, northeastern India? Based on what I read, heard and saw, I'd say the answer is affirmative. Time and again, I noticed it's easier to find a 14-inch lion skull than a 14-inch tiger skull. At the level of individual skulls, however, things are more complicated. Skulls of large male tigers, lengthwise, (almost) compare to skulls of large male lions and my guess, for now, is wild tigers of large subspecies could have (relatively) wider (referring to the arches and the rostrum), and perhaps, heavier skulls. In order to get to a solid conclusion, we need detailed information about skulls of wild tigers in particular. The problem is only few skulls were measured a century ago. In this respect, unfortunately, the situation didn't change a lot in the last century."       

Remember this picture below from https://wildfact.com/forum/topic-on-the-...#pid159586?       

   

If you look closely at Prague Zoo Amur's head, his nose is very elongated. If we try to measure his head from the back of his head to his nose tip with the scale that is already given in the picture which is at 20 cm, it is exactly at 45 cm. But if we try to measure it from the back of his head to his lower teeth on his mandible instead, it is actually around 37 cm. Duisburg Zoo Amur's head seems normal compared to the Amur from the Prague Zoo. Reply