Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 52

Sanskrit:

सत्त्वसङ्गाद‍ृषीन्देवान् रजसासुरमानुषान् ।तमसा भूततिर्यक्त्वं भ्रामितो याति कर्मभि: ॥ ५२ ॥

ITRANS:

sattva-saṅgād ṛṣīn devānrajasāsura-mānuṣāntamasā bhūta-tiryaktvaṁbhrāmito yāti karmabhiḥ

Translation:

Made to wander because of his fruitive work, the conditioned soul, by contact with the mode of goodness, takes birth among the sages or demigods. By contact with the mode of passion he becomes a demon or human being, and by association with the mode of ignorance he takes birth as a ghost or in the animal kingdom.

Purport:

The word tiryaktvam means “the status of an animal,” which includes all lower forms of life, such as beasts, birds, insects, fish and plants.