Biological weathering is weathering caused by plants and animals. Plants and animals release acid forming chemicals that cause weathering and also contribute to the breaking down of rocks and landforms. It is also known as Organic weathering. Its main agents are animals, insects, plants and man. In all the cases, however, both physical disintegration and / or chemical decomposition are involved. 

Their role can be explained as follows : 

1. Animals and Insects : Animals like rabbits, worms, moles and insects bring large quantities of fine material to the surface. Burrowing animals help to loosen the surface materials around the rocks facilitating their physical disintegration. Upon death, the decaying physical also provide many chemicals and acids for rock disintegration. 

2. Vegetation : Roots of large trees reach deep into rocks and cause physical disintegration due to pressure. Most of : vegetation, however, prevents disintegration of rocks because it binds the surface layer and does not allow exposure of rocks beneath to the elements of weathering.