The factors which determine the food of a species are three in number : -

1. The kind of food available, i.e. the character of the local flora and fauna.

2. The specific attractiveness of certain kinds of food, as determined by instinctive prompting for them and by their digestibility.

3. The ability to secure the desired food.

1. The Kind Of Food Available

As to this factor nothing need be said here, except perhaps to remark that it is a matter chiefly determined by latitude.