As of 0.12.1 build 13. I noticed there is no walking sound when spiders are walking near the player.
According to this they should have a walking sound
http://minecraft.gamepedia.com/Pocket_Edition_Alpha_0.12.1
MCPE-10426
Spiders have no walking sound
Resolved
Fixed
1
(Unassigned)
Confirmed
Tablet - Android - Samsung Galaxy Tab 4 Nook
sound_missing
0.12.1 Beta 13, 0.12.1, 0.12.2, 0.12.3
0.13.0 Beta 1
Retrieved
Confirmed on Samsung Galaxy Note 5. Android 5.1.1 Version: 0.12.1