July 7, 2012. A prominent group of scientists; cognitive neuroscientists, neuropharmacologists, neurophysiologists, neuroanatomists and computational neuroscientists gathered at The University of Cambridge, signed the Cambridge Declaration on Consciousness.
"We declare the following:
The absence of a neocortex does not appear to preclude an organism from experiencing affective states. Convergent evidence indicates that non-human animals have the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors.
Consequently, the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Nonhuman animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.”
This means: Animals are conscious and sentient. They register what happens to them and have mental states which can be experienced as positive or negative for them.
The evidence to support this claim is overwhelming.
See the whole declaration HERE.
Some contributors to relevant research on animal consciousness include: