Simple Thing: Animal

Halliday & Matthiessen (1999: 191):

animal

typifying role: active participant in figure of doing [Actor, typically middle, e.g. birds fly].

pronoun it/they; general noun creature; number category: count (singular/ plural).

has potential for self-initiated action and movement [processes in which animal occurs as Actor are (unconscious but) voluntary; and may also be effective, e.g. ... was bitten by a snake]', also for perception [Senser in process of seeing & hearing],