What biological factors affect a meat's taste?
The most significant factors are probably:
Muscle function and activityFat content and distributionDiet of animalAge
Basic muscle structure in most vertebrates is somewhat similar, so taxonomic relatedness is often not paramount in matching flavors. (There appear to be some phylogenetic connections in flavor, particularly among many "beefy" animals, though.)
There's a reason that many people say lots of random meats taste like chicken. Since muscle structure is often quite similar even in very unrelated animals, a lot of reptile and amphibian meat can "taste like chicken." The texture is often different, because muscles may be used in different ways, but if you put th