Kautilya's Arthashastra 2.2.16

2.2.16

saurāṣṭrikāḥ pāñcanadās teṣāṃ pratyavarāḥ smṛtāḥ /[ś]
sarveṣāṃ karmaṇā vīryaṃ javas tejaś ca vardhate //[ś] E

Elephants bred in countries, such as Kálinga, Anga, Karúsa, and the East are the best; those of the Dasárna and western countries are of middle quality; and those of Sauráshtra and Panchajana countries are of low quality. The might and energy of all can, however, be improved by suitable training.