Introduction
This is a realistic rat model with 4K maps, rigging, hair. And UDIM UV is applied to the body for more details. The skin map is made separately for a more realistic effect. The model is made with Blender and Cycles renderer at real-world scale.
The model consists of 6 objects: Body, eyes, claws, oral cavity and teeth, tongue.

Polygons
Body: vertices 18,666; polygons 18,664
Claws: vertices 10,674; polygons 10,368
Eyes: vertices 2,376; polygons 2,368
Oral cavity and teeth: vertices 6,172; polygons 6,132
Tongue: vertices 358; polygons 356
Food: vertices 42; polygons 80
Total: vertices 38,288; polygons 37,968

Formats
There is a Blender project and an OBJ file.

Textures
JU0L506A2_Rat_Body_BaseColor.png, 4096*4096
JU0L506A2_Rat_BodySkin_BaseColor.png, 4096*4096
JU0L506A2_Rat_BodySkin_Normal.png, 4096*4096
JU0L506A2_Rat_BodySkin_Roughness.png, 4096*4096
JU0L506A2_Rat_Eye_BaseColor.png, 4096*4096
JU0L506A2_Rat_Foot_BaseColor.png, 4096*4096
JU0L506A2_Rat_FootSkin_BaseColor.png, 4096*4096
JU0L506A2_Rat_FootSkin_Normal.png, 4096*4096
JU0L506A2_Rat_FootSkin_Roughness.png, 4096*4096
JU0L506A2_Rat_Oralcavity_BaseColor.png, 4096*4096
JU0L506A2_Rat_Oralcavity_Normal.png, 4096*4096
JU0L506A2_Rat_Oralcavity_Roughness.png, 4096*4096
JU0L506A2_Rat_Other_BaseColor.png, 4096*4096
JU0L506A2_Rat_OtherSkin_BaseColor.png, 4096*4096
JU0L506A2_Rat_OtherSkin_Normal.png, 4096*4096
JU0L506A2_Rat_OtherSkin_Roughness.png, 4096*4096

Rigging
CTR_Gravity controls the location and rotation of the body.
CTR_spine_Front controls the location and rotation of the former spine, and comes with multiple customized attributes: IK/FK_Head_Follow, IK/FK_Neck_Follow, HandFollow Body, Neck_IK/FK, Tail_Follow, Tail_IK/FK.
CTR_foot_H.L/R controls the movement of hind legs, and comes with the customized attributes: L/R_IK_Ankle_Roll_Loc, Leg_IK/FK.
CTR_foot_F.L/R controls the movement of forelegs, and comes with the customized attributes: Leg_IK/FK.
Each toe has a separate controller.
There is a UI for facial rigging, which is used to animate the eyes, eyebrows, lips and nose for some simple facial expressions.
And more …

Features
The model is in meter units at real-world scale.
The model applies UDIM UV.
The rigged version is in the initial pose, previews are just for display.
Shape keys are applied to fix abnormal deformations.
To reset the initial pose, select all the controllers in pose mode, then press Alt+R, Alt+G, and Alt+S and reset the shape key of the body to 0.