This picture shows four renders made with the same texturemaps, and different setings for the base colours in Poser 5. The texturemap is for a grey-furred creature, and it being used with Little_Dragon's Mia figure, the Millenium Catwoman (with the BreastsMale morph applied, and other additions off-camera).

Picture 1 is the baseline, with the diffuse base colour set to white, and a very dark specular colour. On the body, there is a low-value displacement-map setting, fed with the standard Mia bump-map. None of the pictures use a bump map or displacement map on the head.

Picture 2 applies the body texture to the specular color input, and sets the base colour to white. As you can see, there is a slight brightening of the highlights, but they're still dominated by the displacement effects on the body.

Picture 3 removes the displacement mapping and darkens the base colours for both diffuse and specular inputs. As you can see, we've lost a lot of the surface texture, though the shape of the figure isn't lost in the black. The base is somewhere around 50% grey.

Picture 4 is the final step. The grey texturemap, used all the way through, is now applied the displacement input. Because it's a dark grey, it can be used at quite a high displacement value. The resulting reflection pattern isn't quite the same as Picture 2, and you can also see how it affects the average tone.

Incidentally, it's worth remembering that the base colour for black hair or fur isn't a neutral shade. Not only is it something less than an absolute black, it relies on the same pigment as dark skin, whether from a suntan or ancestry. Try a very dark red; these images maybe have a little too much green.

It's also worth remembering that the resolution of the texturemap can affect some things. These are probably a little bit too low-res for close work such as this.