[3] Various species of Planaria have been widely used as model invertebrate organisms in pharmacological research, in particular in the studies of the drugs of abuse.

[6] Planaria originally have habitats in dark, murky water which results in such sensitivity (Paskin et al., 2014).

They are also sensitive to other stimuli such as chemical gradients, vibration, magnetic and electric fields (Deochand et al., 2018).

Their central nervous system includes the anterior (head, brain and eyes) and middle (abdominal trunk and pharynx) (Deochand et al., 2018).

[7] In the United Kingdom, P. torva is a successful predator of the invasive New Zealand mud snail (Potamopyrgus jenkinsi).