Urdu marginal note: Predatory animal skins are generally used by arrogant people, therefore their use has been prohibited, just as Muslim men have been prohibited from using gold and silk. The skins of lions, leopards, etc., were commonly used. It is possible that they were used without tanning, but this is a less likely possibility. The correct view is the first one.
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 4258