Hey,
Well for starters there is that all inclusive and unforgettable color difference which should in most cases be your first hint to what the animal is. For instance: Black bloods, tend to be darker in color with fewer definable saddles as the animal matures. They have orange eyes with granular (suboculars) scales just beneath the eye making contact with the junction of the supra-labial lip scales. Females can get to lengths of 5ft, while males only reach lengths of 4-4.5ft total. There are exceptions to these lengths given.
Their temperment is described as being less tempermental than the other short-tails, but I've yet to meet a nasty Borneo short-tail.
Borneo's, are stoutly built too, and are larger than Sumatran Short-tails (Black bloods), with a brown to dark brown or dark or light tan background color with brownish to saddle brown saddles or blotches. Some individuals may possess a posterior stripe, running the length of the lower third of the body towards the tail dorsally. Their eyes too, can be orange in some animals, and you will also find that they have granular (suboculars) scales just beneath the eyes, making contact with the junction of the supra-labial scales.
They are more heavily built than the Sumatran Short-tails, and get larger too, with females reaching lengths of 5-6ft in length, and males getting from 4.5ft-5.5ft. There are recent reports of larger individuals, but these are the norms.
For a more detailed description to the morphology and phenotype differences of the two described short-tails, you should read the paper written by:
J. Scott Keogh, Dave Barker and Richard Shine.
If you need a copy of it email me and I will send you a copy.
Hope this helps.
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In the theater of my life, this pickle has no goal!!