Hearing noises of mobs and lava that isn't there

Hearing noises of mobs and lava that isn't there

What I expected to happen was...:
None of this

What actually happened was...:
Am playing on an survival island in the middle of the ocean, only sheep and chickens on the island. Cleared out all the lava. Can hear the sounds of cows and lava, even though there is none. Installed an x-ray texture pack just to be sure.

Steps to Reproduce:
1. I'm not sure