This comes down to a difference of approaches. People naturally anthropomorphise pets and dogs have abused this by evolving expressive eyebrows so that humans bonded with them easier. The grills of cars are designed like a smiley because people recognise the headlights as eyes and attribute emotions to unfeeling metal objects based on the shape of the air intakes and panels.

If all the chemistry and physics that make up an animal are all there is to life, then it’s not hard to reason about animal intelligence. There are things we consider to be very basic (pointing at something and expecting someone else to look at what we’re pointing to) that very few animals can grasp. There are special tests to determine self awareness, like if an animal can recognise a spot drawn on its body in the mirror.

Humans lack knowledge of animal interactions (and sometimes senses) to clearly determine what animals are communicating to us. We like to attribute intelligence to dogs and other common pets that look like us mammals, but squid and birds can beat intelligence tests that human toddlers struggle with.

There is also the philosophical approach. Do animals feel? Do they posses a soul? We have no way to exchange words with animals, so we’ll likely never find out. There has not been any proof of a soul in humans, but if you believe humans do have some kind of ethereal component that’s not visible to the naked eye, it’s not hard to imagine animals may have something similar.

Some people like to pretend we as humans are super special and above animals. I don’t buy that, I think we’re just smart monkeys, nothing more, and our emotions are just more complicated forms of “behaviourisms” we see in other animals. We do possess some insight that many animals clearly lack, but cats certainly do feel joy or loss. Cats are known to grieve, as are many other animals. Of course, they don’t have the spiritual concepts we do, and once they’ve processed the loss of their friend, they’ll probably eat the body if there are no other easy ways to find food, but to consider any mammal an emotionless creature that’s more akin to a robot than a living thing is nothing but a superiority complex.

Mollusks are some of the basic forms of animal we know of. They respond to chemical cues, just like us, but there’s no proof whatsoever that they possess any kind of mental faculties beyond basic responses. Maybe they do have a soul and maybe they have intricate love lives, but we haven’t found any evidence for that yet.

We may never find out. If mollusks do experience emotions, there’s a chance their emotions are nothing like ours. We explain emotional responses through happiness, fear, anger and all that stuff, but who says other animals feel the same? Perhaps sea creatures have an emotional spectrum comprised of degrencre, humber, nage, and dorcelessness, but we’ll never be able to understand those, let alone recognise them when animals express them.