Better Than Wolves was a total conversion mod of Minecraft version 1.5.2 created by FlowerChild and uploaded to the Minecraft Forums. Its intention was to introduce numerous items and mechanics into Minecraft to give it both new variety and new challenges. As of April 9th 2021, the mod and all its code has been released under Creative Commons Attribution 4.0 International Public License, and the mod creator has ceased development on it.
As of writing, you can still view the Better Than Wolves Wiki for installation instructions, and information about the mod itself.
Here's a useful wiki page of older mod versions you might be looking for. I'll post a couple notable ones here.
1.0 (Beta 1.4_01)
1.24 (Latest for Beta 1.4_01) (Requires Modloader b1.4_01)
2.94 (Latest for Beta 1.7.3) (Requires Forge 1.0.6 OR Modloader b1.7.3)
3.22 (Latest for Beta 1.8.1) (Requires Forge 1.1.0 OR Modloader b1.8.1)
3.91 (Latest for 1.2.5) (Requires Modloader 1.2.5)
As pointed out in the code's original Readme, since the project is a total conversion, it might contain modified versions of Mojang's code and assets. It is up to the distributor to appropriately consider Mojang's intellectual property, licensing, and EULA.