It must be noted that in the past, our Rishi Munis and Tapasvinis usually had their ashrams situated in remote places, away from populated regions. The skin of the dead animals that were used for seats or asanas, were more available in those remote places than cloth materials such as jute or silk or cotton, etc. In fact, ‘mriga-charma’ – skins of deer, is prescribed for asanas, since the deer was always a part of the ancient ashrams. To those living in jungles, tiger-skins was also easily available. Hence, the prevalent use of deer or tiger skins as asanas. What should be understood is that never was any animal killed for obtaining its skin, as happens in today’s commercialized society. Also, the sages found that doing sadhana while seated on a deer-skin, was highly conducive to spiritual growth.