This is a hunting game published by Activision.
The Data file (DATA.ARC) is compressed but can be decompressed with the tools "Game Extractor"
http://www.watto.org/extract

The basic format for the animal models is simple: Just a large 12byte array of Vertexes followed by a 8byte array of texture UV coordinates.
The mesh's faces are defined implicitly by connecting 3 adjoining vertexes at a time.
The meshes are contained in the \OBJECTS and end in the extension .SKIN

lionuvbgh2008.jpg


liontexture.jpg


bear.png


A bear model.
leopard.jpg
The converted main texture for the leopard.

PS2 Version: BGH 2008

Files Extensions:
.AP
.BAT
.BSP
.CFG
.DEF
.EXP
.FF
.FNT Fonts
.FX
.GRASS
.ICO
.LOG
.MAT
.MODEL
.MTP
.PLOT
.PST Textures (??)
.RES
.SCR
.SCRIPT
.SKIN
.SND
.SPJ
.SPL
.TXT
.VAG Audio
.XSC

Every .SKIN file contain geometry data regardless it is an animal or water.
A subheader inside the file more closely defines the type of mesh.
In each .SKIN animal mesh file the first four byts are the text:
"FBSF" and the hex bytes "12 04"
followed by 4 unknown bytes that change with each model and the text without the quotes:
"Make Model (build 1085 - Aug 14 2007)"
This is probably an internal tool used to compile the meshes.
This 48 byte header is in every .Skin file.
Then there are 4 empty bytes:
00 00 00 00
Followed by the length of the text string of the corresponding
.model file:
example: 0C weasel.model
followed by:
00 01 00
followed by the length of the text string:
07 Default 01 00
followed by the length of the text string:
06 weasel E3 EF
followed by
?? ?? ?? 00 01 00
followed by the text string:
08 ModelLOD
followed by a weight which is normally -1:
00 00 80 BF
followed by:
01 00 07 MeshRSD
followed by:
00 00 00 00 00 00 10 RSDBlendedLitPS2
followed by:
04 00 00 01 17 00 04 00 ?bone?
where ?bone? is the 4byte number of bones that
the mesh has.
For each bone the length of the bone name followed by the
bone name with no spaces in between for example:
07 BipHead 08 BipRFoot 0A BipRfinger.....

It should be noted that the bones are given the same
names regardless of the animal.
Right after the whole list is the bones positions for each bone in the list.
StartBoneX, StartBoneY, StartBoneZ, EndBoneX, EndBoneY, EndBoneZ
followed by:
01 00 00 00 2Byte#Vertex 01 00 ?bone? 00 00 00 00 00 00

where 2Byte#Vertex is the number of vertexes
in the model.

This is followed by a weight:
Weight1, Weight2, Weight3, Weight4, Weight5, Weight6
where each weight component is a 4byte floating point.

This is followed by:
a listing of each bone counting from 00 to ?bone? -1
for example with 5 bones it is:
00 01 02 03 04

This is followed by
2byte#Vertex
which is followed by the connection bytes which is 4bytes for each vertex:

?? ?? ?? {01}

In this game each 4th byte is almost always 01.
Followed by all of the Vertexes position:
verX, verY, verZ,
Followed by all of the unit sphere normals

Then Followed by all of the UV texture coordinates:
texX, texY

Other closely related formats are
RSDRigidLitPS2 used for Boats
and Horns/Antlers which the game uses the term Antlers even if it is a horn

RSDPertRRPS2 used for water

RSRigidPrelitPS2 used for camp fires and level terrain

PC Version: BGH 2008

The meshes for the animals in the PC version are also in the .SKIN files
with the subtype "MeshBlendedPrelit"
These files contain 3 complete meshes: One high detail mesh, One low detail mesh, and one skeletal mesh.
{4ByteFloatVertexes(X,Y,Z) 4ByteFloatNormalMappings(X,Y,Z) FF FF FF FF 4ByteFloatTextureMappings(U,V)}
.... 2ByteFaceIndex(Vertex#1,Vertex#2,Vertex#3)
... BONES: BeginningBone(4ByteFloat(X,Y,Z)), EndBone(4ByteFloat(X,Y,Z))