Like I said, our idea – that is, our presumption, short of scientific evidence – of what inner experiences an animal might share with us should be informed by our knowledge of what physiology and behavior that animal shares with us. Orcas are mammals with complex social structures who form extremely close bonds with their mothers [1]. Hence my suggestion that the burden of proof rests with those who claim that an orca would not feel grief should her child die.

Roundworms? Not so much.

[1] https://en.wikipedia.org/wiki/Killer_whale#Social_structure