How long does it take for corpses to disappear from the towns and countryside? Are there a mod that can delete the corpses?

Anywhere from around 15-30 in game days.

Is the Khajiit near a Forsworn Fort?

There is probably a console command to clear the body you point at.

What is the purpose of semi-permanent corpses? Why not disappear in minutes or dispose of corpse like Morrowind so as not to clutter the game?

So you can walk by and say, "Yeah, you better lie there and rot. Next time, don't be stupid to come after me, idiot wolf."

I like them lying about. Adds a sense of realism.

Note: If stamina is high enough, you can press and hold "A" (360) and pick them up and move them. I usually throw wolf carcasses in the river.

Moving bodies and items doesnt use stamina.

Is the stomach exploded? Maybe the smuggled drugs fermented and boom

You can delete the corpses using the console.

Just open the console using ~ , Click on the corpse and type markfordelete, then enter. Next time the area is loaded, they will be removed from the game and your save file.

I would recommend doing a quick save before doing this, as it is sometimes tricky to select the right thing. After using the command on the corpse, try opening their inventory. If it doesn't let you, you've selected the proper thing for deletion.

I will try this. In Oblivion I used a spell that instantly deleted them, very useful. I guess some one could create randomwondering rat packs that 'eat' the corpses which would add to immersion.

I will try this. In Oblivion I used a spell that instantly deleted them, very useful. I guess some one could create randomwondering rat packs that 'eat' the corpses which would add to immersion.

True, but adding levels to stamina increases carry weight, which is needed to move larger animals.

If you use the unofficial patches, corpses disappear very quickly. Weapons and shields are also bound to any NPC's inventory, so they disappear with the NPC (you access the NPC's inventory even when clicking on the weapon and/or shield). Arrows disappear quickly also. The unofficial patches save a lot of trouble when it comes to clutter, but make sure you have all you want from the corpses...

I have all Artmoor's patches yet no difference. I also have Bash Patch that could have overridden the patches. I just tried markfordelete, I will see if that works.

you can always try to loot them, nothing like getting some free gold or weapons!!