Modern weights and measurements on wild tigers

[peter]

In Russia, young males disperse between 18-24 months of age. In India, they seem to disperse between 24-30 months. This although conditions in India are better. The most likely reason is small reserves, no buffer zones and intense competition. For this reason, young males can be as heavy as mature animals.    

My advice is to distinguish between adolescents (2-3), young adults (4-5), prime males (6-10) and old tigers (11 and over). In skulls, the distinction between age classes often is well visible.

When you have information about individuals, try to contact those in the know to check what you have (Copters proved it can be done). Maybe they can tell you a bit more about fluctuations (collars often are replaced) and it's possible they also have info about total length. When you have weights, try to find out if the tigers were empty or not when they were weighed. Also try to find out a bit more about the scales used.

In order to get to an assessment, we need large samples. The larger the sample, the more reliable the table. My guess is there are 500-800 adult male tigers in India today. Read a bit about sample size, statistics and conclusions.          

When done, also try to get to a conclusion on reliability (referring to the sources used). I'd distinguish between low, medium and high.

And then there's regions. Based on old records, there could be pronounced differences between the elevated Himalayas (the Terai, Nepal and Bhutan), the alluvial floodplains in the northeast (like Kazirangha), the wetlands in the Ganges and Bhramaputra delta (the Sunderbans), the highlands of central and central-eastern India (like Kanha), the plateau of southern India (the Deccan) and southwestern India (the western Ghats).   

The reason to publish tables in WildFact is a lack of data in peer-reviewed documents. In some documents, the data are unreliable because weights were adjusted. Sizewise, peer-reviewed not always has meaning. The reason is only few biologists are interested in size (a lack of interest can result in a lack of knowledge). This is the reason old data are used so often. Also remember most samples are small, which could result in bias.   

Our aim is to collect data and enable readers to get to an opinion. What we don't want, is tables based on newspaper reports only. This is a very real danger. For example. I've read a number of reports about the large male who was moved from Ranthambore after he had killed four humans. In nearly each of them, the weight mentioned was different. He wasn't the only one.

I know it's quite a job, but it's the only way to get to decent tables. Good luck. Reply