We have various neurotransmitters that cause pleasure or feelings of love in humans. Do they work in this way for all other animals and organisms ? What about reptiles, insects, crustaceans ?
I don't know how far science is assuming the state of subjective experience in other organisms, but how far can we say that other organisms would feel the effects of neurotransmitters in ways that we would recognise from our own experience ? For instance, we could assume that another primate experiences dopamine in a similar thing to humans, but what about non-mammals, animals of other classes ?