Animals don’t reason other than it is clear that the very smartest can in fact do so (Corvids) and many predators. And the demarcation between sentience and consciousness is the mirror test. And some animals can pass it – even possibly pigeons.
Many animals dream so they must ‘think’ at whatever level it is that they dream.
But when we say ‘think’ we can mean ‘feel your way thru something’, visualize your way thru something, plan your way through something using tools, reason (talk) your way thru something, and explain to others how to act through something.
To say animals are sentient is true, to say they are conscious -
well there are some that appear to be.
To say they are rational, it is not clear that all people are rational, or that we are fooled that they are rational because they are capable of language, and language creates the illusion of similarity.
The more we learn the more the gradual progress from nervous system to sentience, to consciousness is just as continuous as the spectrum from feminine pschosis to feminine solipsism to normal balanced personality, to male aspieness, to male autism.