There can be little doubt that Plutarch composed this pleasant work from commentarii (ὑπομνήματα) derived not merely from Aristotle (mentioned specifically in 965 d and quoted often), but also from various other compendia, the remains of which are to be seen in Aelian’s and Pliny’s natural histories and elsewhere.On the sources see Ziegler’s article Plutarchos in Pauly-Wissowa, col. 738, and, of the authorities he cites, particularly Wellmann’s papers in Hermes, xxvi, xxvii, and li, and Max Schuster, Untersuchungen zu Plutarchs De Sollertia Animalium (Diss. Munich, 1917). There is also an amusing work of Philo, surviving only in an Armenian version, which is most conveniently accessible in Aucher’s Latin translation in vol. 8 of the Bibliotheca Sacra edition (Schwickert, Leipzig, 1830): De Ratione quam habere etiam Bruta Animalia dicebat Alexander. In the first part of this work Alexander presents the arguments for animal intelligence, which Philo himself attempts to refute in a somewhat summary fashion at the end. The occasional parallels with Plutarch will be cited as Philo, with Aucher’s section and page numbers. Antigonus of Carystus, Historia Mirabilium, will be cited from O. Keller’s edition of the Naturalium Rerum Scriptores Graeci (Teubner, 1877) and Aelian’s De Natura Animalium from R. Hercher’s Teubner (not Didot) edition. In fact, if one reads Plutarch and Aelian and Pliny side by side, one may acquire the impression that they had before them substantially the same sources, and that these were numerous. Whereas Pliny and Aelian appear to adopt nearly everything their authorities may have offered (for they were writing factual commentaries), Plutarch, as always, selects. It is possible, in some cases, that Plutarch’s mss. (which are not good and also contain lacunae) may have been interpolated from Aelian’s; and the reverse is likewise possible. This is a very difficult matter, but the hope may be entertained that some main sources of Plutarch and Aelian, if not of Pliny, and the as yet unassessed evidence of Philo, may eventually be disentangled for substantial sections, though this is not the place to attempt such a feat.
