... a didactic poem, especially such with animals as characters may be distinctively described as...

… a didactic poem, especially such with animals as characters may be distinctively described as a/an_________

An Apologue is that type of moral fable with animals as characters. It usually conveys both surface and deeper meanings.

There is an explanation video available below.

… a didactic poem, especially such with animals as characters may be distinctively described as…