Daba tasar and oak tasar are the two well known non-mulberry tasar silks in India. They are wild in nature and classified as tropical and temperate tasar depending on the region of cultivation. While Daba tasar belongs the species of Antheraea mylitta D. and is a pure race, the oak tasar is the interspecific hybridised product of Antheraea roylei and Antheraea pernyi which makes Antheraea proylei J. The bivoltine mulberry silk is generated from the species of Bombyx mori L and is a cultivated variety.

Silk, being a natural product, inherently contains some amount of variation in all its characteristics. It is not only important to understand the extent of variability present in its various physical and mechanical properties but also to know whether there exists any pattern in its characteristics while unravelling from its cocoons. Such a pattern may lead to bring a perceptible change in the appearance of the final product.

A study was conducted to understand the progressive change in the characteristics of filament along its length in Daba tasar , Oak tasar and Bivoltine mulberry varieties of cocoons available from three different regions of India, i.e., Bihar, Uttar Pradesh and Karnataka, respectively.