Aelian: περὶ ζῴων ἰδιότητος – On the Characteristics of Animals [=NA]
The Loeb parallel English translation is available at the Internet Archive as a scanned copy. Also at the Internet Archive is a scanned copy of Hercher's 1858 Greek text with parallel Latin translation, while a HTML version of the Latin translation from Jacobs' 1832 edition is available from LacusCurtius. Hercher's Greek text is available in HTML version from Perseus. 



https://archive.org/search.php?query=aelian%20AND%20loebAelian, trans. Scholfield (1958–1959) On Animals (3 vols). Cambridge, Mass; London: Harvard University Press; Heinemann. —Volume I: Books 1–5; Volume II: 6–11; Volume III: 12–17.

Aelian, ed. Jacobs (1832) Aeliani de natura animalium libri xvii. Jena: F. Frommann. —Text in Greek with translation, commentary and notes in Latin. URL links to HTML version made available by Bill Thayer. http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Aelian/home.html. 

Book I   II   III   IV   V   VI   VII   VIII   IX   X   XI   XII   XIII   XIV   XV   XVI   XVII

 
Aelian, Porphyry, and Philo of Byzantium, ed. Hercher (1858) Aeliani: de natura animalium; varia historia; epistolae et fragmenta. Porphyrii philosophi: de abstinentia; de antro nympharum. Philonis Byzantii: de septem orbis spectaculis. Paris: A.F. Didot. http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3atext%3a2008.01.0590