Life is an emergent attribute of advanced complexity organic chemistry, typically differentiated by self-reproduction and movement. The root of ethics is that simple avoid/approach mechanism. An animal is a higher order of complexity of life, differentiated in many ways.
Mind is a metaphor for the patterns in the brain. A thought is a pattern of change in a mind. In that mundane sense an animal have thoughts. To say a creature is thinking adds intent, a mindful contemplation with intent. That requires a certain level of self-awareness and external contemplation.
Consciousness is a scale of awareness and not all species or members of a species has access to any particular level of awareness.
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Roughly speaking we draw the line between creatures and animals at sentience, an advanced complexity avoidance system. The line between animal and human is cognition, intentionality, an advanced complexity approach system. So an animal is a form of life that is definitely sentient and definitely not mindful.
None of these words is technically specific so the edges are constantly debated.
I think emergence is key here, chemistry emerges from physics, biology emerges from chemistry, psychology emerges from biology and so on..