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

[peter]

GRIZZLY

Thanks for the info. I've measured about 400 big cat skulls, but never saw a pm4 reaching 40 mm, let alone 42 mm. The large molars no doubt were an adaption to the animals they hunted. Indian tigers, and those living on the alluvial plains in the northeastern part in particular, still hunt large herbivores. I never measured the skull of a male tiger from, say, Kaziranga, but it even seems to show in skulls of captive Indian tigers. Compared to those of captive Amur tigers, they are a bit more massive (relatively heavier). The length and width of the upper canines in Amur tiger skulls, however, is unsurpassed. Amur tiger skulls also are longer.  

As to the evolution of tigers. Guate wrote a few posts (this thread), but that was a long time ago. My guess is our readers would appreciate a bit more about the difference between Late Pleistocene tigers and those populating Asia today. They know tigers nearly vanished after the Toba eruption about 75,000 years ago and repopulated parts of southern, western and northern Asia in different waves, but that's about it. 

How were tigers able to recover and why do you think Amur tigers are more closely related to Late Pleistocene tigers than other subspecies? 

Some years ago, in this thread, I discussed a document of Baryshnikov about the bones found in a number of caves in southeastern Russia. The skulls suggest Late Pleistocene lions, although smaller than those from eastern Europe and the western part of Russia, were still larger than those of the tigers inhabiting the same caves some time later. The tiger bones suggest they, sizewise, more or less compared to today's Amur tigers. 

After the lions disappeared, tigers, most probably, increased in size in the Late Pleistocene and early Holocene. The owner of the skull below was a very large male. I've never seen anything come close in the natural history museums I visited:

*This image is copyright of its original author

Could it be the skull of Late Pleistocene tigers was an adaption to hunting powerful animals like wild boars? Ussuri wild boars are the largest in the world by a margin. 

I don't know if the skull below is from an Ussuri wild boar, but the owner allegedly was 354 kg. It's massive in all respects. The other skull is from an adult wolf:

*This image is copyright of its original author

Here's another photograph (ventral view) of a skull of an Ussuri wild boar (top) and the skull of a Sardinian wild boar in order to show the size of the Ussuri wild boar skull. This photograph was also posted at Carnivora some years ago. I got both photographs from a former member of Wildfact:

*This image is copyright of its original author

Indian tigers, like I said above, still hunt large herbivores. Although some males living in the northeastern part are massive and big-skulled, they still do not come close to their relatives from the Late Pleistocene and early Holocene. Why is that? 

Unfortunately, I can't join the discussion at the moment. The reason is I'm trying to contact the authors of a paper discussed some years ago (in this thread). One of the captive Amur tigers they discussed (a male shot in the Koln Zoo in 2012) was one of the largest I know of. In spite of his age (the tiger was only 4 years old when it was shot), he was long (HB 240 cm, tail 96,5 cm and total length 336,5 cm) and massive. The photographs of the skull, even allowing for the angle, suggest it was longer than the skull of the adult wild male Amur tiger V. Mazak measured in the Berlin natural history museum some decades ago (383 mm). My aim is to measure and photograph the skull this year. 

Here's a photograph of the skull. Watch the scale at the bottom:

*This image is copyright of its original author

This, for comparison, is the skull of a wild adult male Caspian tiger shot in 1959: 

*This image is copyright of its original author

Recent research says Panthera tigris virgata and Panthera tigris altaica are closely related, but the skulls I saw point in another direction. The profile of the upper skull of nearly all captive Amur tigers I saw is flatter than in all other subspecies. The upper skull of Caspian tigers (referring to photographs, drawings and descriptions), on the other hand, is as vaulted as those of tigers in southeastern Asia.  

The skull below is from a different male, but the profile seems (also referring to the description of Panthera tigris virgata in 'Der Tiger', v. Mazak, 1983) to be typical for Caspian tigers:

*This image is copyright of its original author

 

There are more structural differences. Mandibulas of Amur tigers are nearly always straight, whereas those of Caspian tigers often seem to be more concave. As a general rule, skulls of (captive) Amur tigers are longer and the upper canines are both longer and heavier. As a result of the larger upper canines, rostrums of Amur tigers are (absolutely and relatively) wider and stronger. It's almost a different animal. 

Anyhow. See what you can do. Reply