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

[peter]

02 - EVOLUTION

Tigers very probably evolved in the south-eastern part of China and the north-eastern part of Indochina roundabout 2 million years ago. Many researchers think they spread from there in different waves.

The first wave ended in Java, whereas the last was directed at the region between and just south of the Black and the Caspian Seas. The last wave probably ended 10.000-12.000 years ago and originated in northern China. As researchers found no significant differences between Panthera tigris virgata (the Caspian tiger) and Panthera tigris altaica (the Amur tiger), we have to assume they probably are, or more accurately were, one and the same.

Another quite recent wave south of the Himalayas ended in the extreme north-west of India. Kashmir and the Indus River could have been the most northerly and westerly limits. Tigers in central and southern parts of India seem to be somewhat different from those in the north of India, suggesting they could have entered India before the new wave entered north India. This would, at least partly, explain the differences seen between both populations.

The story on Sumatran tigers is quite complicated. It is very likely Sumatra was populated by tigers from the first wave and it is also likely they completely vanished as a result of the Toba eruption some 75.000-80.000 years ago. After the eruption, Sumatra was re-populated from both Java and Malaysia. This would explain the remarkable variation seen in Sumatran tigers. The differences between them and other subspecies is of such dimensions that researchers proposed to change Panthera tigris sumatrae to Panthera sumatrae. A prototype of the true tiger, that is. I have some doubts, but there is no question all island tigers are quite different from mainland tigers in many respects.

Recent research suggests Bali tigers were more related to Java tigers than to any other regional type. The skulls I saw confirm they probably were closely related. Today, Panthera tigris balica is seen as a subspecies of the Java tiger. As the Java tiger changed from Panthera tigris sondaica to Panthera sondaica, the correct name for the Bali tiger is Panthera sondaica balica. The Bali tiger became extinct in the late fifties of the last century.

In most models used to predict the presence of tigers, it was assumed tigers, as a rule, would avoid elevated, arid and open regions. J.F. Brandt (1856), after reading everything written on tigers in his day, however concluded tigers were present and even quite numerous in northern and eastern parts of Tibet as well as in barren and elevated regions of Central-China. A recent expedition confirmed tigers live and breed in suited regions of Bhutan at 10.000-12.000 feet. Tigers were also reported in eastern parts of Afghanistan only recently. This means assumptions about the most likely route tiger followed when they spread towards the Caspian could have to be revised.

Afghanistan, tigerwise, is somewhat unclear. There are too many recent reports on tigers to be dismissed out of hand, but it also is a fact not one expedition produced strong evidence of tigers living in Afghanistan today.

Many assume Javan tigers became extinct in the seventies or eighties of the last century, but there are persistent rumours about big cats in isolated parts of south-central and eastern Java. Although no evidence was produced so far, leopards were eliminated as candidates. Unclear.

In the last decade, many interesting articles on the evolution of tigers have been published. These strongly suggest the classification proposed by R.I. Pocock in his article on tigers of 1929 (first published in the Journal of the Bombay Natural History Society) can no longer be used as a 'working-hypothesis'. Reply