Noted- Smooth corrective is not working in sketchfab . 

Castoridae 3D Beaver Model ,Original Blend file.

Low poly

Unreal Unity Compatible .

Game Ready Animations 12x .

4K Textures Diffuse Metallic Roughness Normal Maps . 

Pls Check the 3D sketchfab preview quality first and in the blender , with smooth corrective is much better. Thank you.