Prayer: When Only Clothing from Predatory or Unlawful Animals is Available
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 828
If a person does not have clothing other than that made from a predatory animal, in the event that he is compelled to wear it, he can perform prayers with it provided that the necessity for him to do so remains until the end of the prescribed time. However, if he is not compelled, he must perform prayers according to the instructions that were mentioned regarding a naked person. If a person does not have clothing other than that made from an animal whose meat is unlawful to eat but is not a predatory animal, in the event that he is not compelled to wear it, the obligatory precaution is that he must perform prayers twice: once with that clothing, and once according to the instructions that were mentioned regarding a naked person.
-Ayatullah Sistani, Practical Laws of Islam, Prayer (Salah)