From this description
, I'm sure it's a fairly heavy duty outdoor knife. The blade shape comes from the same tradition that gave us chef's knives at one end and bowies at another.
"The punal is the very model of a Spanish "dagger" of the 18th Century. Not a dagger at all but what appears to be a French chef's knife with a thicker blade and often a handle and sheath of silver or nickel silver."