AFAIK Rawhide is just that - hide in a raw form. All the hair, fat, etc has been removed but rawhide is not leather. ie it does not undergo any tanning. Traditionally it is dried on a stretcher and once taken off it is very stiff indeed, as it should be, being a bit of sundried animal hide. It is then worked to make it soft and pliable (if necessary - the stuff used for dog chews, etc, is rawhide and this is very stiff). some methods involve pulling it round a smooth thin diameter stick many times (this works for tanned leather strops too, and was used when russian leather really was russian leather and simply had to be broken in) or putting it in your mouth and chewing it.

When it is very soft, it is too soft for a strop - it stretches and gives a lot. When it is too stiff it is unsuitable for a strop, as it can be harder and stiffer than any tanned leather.

When I watched westerns as a kid, the movie plot often involved indians wrapping wet rawhide around the chests of cowboys and leaving them in the sun. The rawhide hardened and shrank, breaking all their ribs. I thought this was fanciful until I was much older, then learned that it could be used to wrap and bind wood, particularly in the making of saddle trees, but that the wood had to be selected carefully as once dry the rawhide could break it.

As a point of interest, chamois leather ("shammy leather' or "wash leather") is defined in the US as being untanned, thus it is a type of rawhide. However, in the US it is produced infused with oils. The same can be done to rawhide to impart a degree of water-proofing and softening.

Regards,
Neil