Which animals should be considered sentient in the eyes of the law?

Jonathan Birch in The Guardian:

An insect’s brain is organised completely differently from a mammal’s. It is also much smaller (a bee has about 1m neurons, compared with our 100bn). Could insects be robot-like evolved machines with absolutely no experience or feeling? Or are we underestimating what a small brain can do?

New laws to impose some consistency in this area have been needed for a while. So the animal welfare (sentience) bill, introduced to parliament on Thursday, is a welcome development, as is the creation of an animal sentience committee. The bill includes vertebrates by default, but explicitly allows invertebrates to be added through statutory instruments. I can see the rationale for such an approach in an area where the science is moving quickly.

For instance, on the question of insect sentience, scientists are divided, partly because there has been no serious attempt to look for sentience in insects.

More here.