Hello everyone, and thank you all for your interest in this unique piece.
Detlef, The knife has a total length of 13-1/2 inches while the blade is 9 inches long, 1 inch at its widest and is slightly under 3/16 thick. I would agree with your dating on that this was made sometime in the second quarter of the 20th century, 1930-1950. I should have added this information in my original posting.
Jose, I'm not sure either on what it represents either and was hoping to find that answer here. I think that Lorenz once posted something about dogs being revered in some areas of the Philippines, but no luck so far in finding the information. I think that I will drop him an email to see what his thoughts are on this piece.
Vandoo, I am pretty sure that this representation is of a dogs and not a bats head. I searched through many photos of fruit bats/flying foxes as well as other bats trying to find one that might match this with no luck. While the ears do seem to be somewhat batlike the nose and muzzle of this are a no match as far as bats go but do seem to match that of a canine. These are just my observation though and could very easily be wrong. On the blade, I have seen some tenegre with blades that are similar in style to this ones posted here on the forum.
Dimasalang, You might very well be right.