They absolutely do! Some animals mate for life. Some mourn when one of their own dies (see whales, elephants). Parrots who are lonely may self-mutilate. Dogs can remember you and get so excited to see you, even after being separated for years. Interspecies friendships exist. It's like... I don't see how people can still think animals DON'T have emotions.

They just don't make faces like humans do. Although interestingly, dogs developed eyebrow muscles that give them more human-like expressions, which therefore strengthens our bond with them.

No, only humans are capable of thought and emotion. every other animal on this planet is just running a basic logic loop and will despawn if you move more than 100 yards away from them.

I don't think I've ever seen dogs, cats and other domestic animals smile because they're happy

The dog wags it's tail to show happiness/excitement. Come on, have you never heard about that?

"Smiling" = showing the teeth would indicate a threat of aggression.

Do animals feel love and emotion?

Yes. Animals absolutely have emotions. In fact, many animals, like cats, are extremely emotional creatures, on account of not having as highly developed parts of the brain that deal with emotional regulation. Affection? Absolutely. Love? Yes, but not generally in the same ways as people.

Do cats and dogs actually feel affection when you treat them right or is it really just an instinct for "more food and drink" etc?

I have a little cat that adores me. He likes come right up to my face and head-butt me forcefully (a behavior called bunting) and he likes to fall asleep gazing at me. Domestic cats and dogs are social creatures. Left to their own devices, they will engage in social behaviors unrelated to survival and biology.

I don't think I've ever seen dogs, cats and other domestic animals smile because they're happy and show love to their owners for treating them right.

Oh they absolutely do smile, just differently than humans. Cats are especially subtle abd communicative in their body language. It's also with noting that what humans think of as smiling, to most animals is an aggression display.

Yeah I see memes but those are either photoshopped or snapped at the perfect moment to make it look like they're smiling.

Domestic dogs and cats communicate a lot with body language, the majority of it being pure emotion. Their body language, however, is different from our own. You have to meet them halfway in communication; learning to listen to what they are saying.

Smiling with the mouth isn't a universal expression, different animals express happiness in different ways

Absolutely! There are studies which show that cats develop affection for their owners, and have several ways of making that affection known. Dolphins are able to feel both love and also grief and there's a growing amount of research which shows that birds are able to feel joy, love and grief. Many animals also mate for life!

Not only dogs and cats are individuals who have their own way of showing how they feel and how much they love you.

Most people would probably switch to a vegan lifestyle if they realised how much we underestimate animals (and overestimate ourselves)

They definitely do show sympathy, sadness, fear and joy, which are unrelated to being rewarded with food and trained behaviour.

I don't see why they shouldn't have a full range of emotions. It seems simpler and more natural than developing a transactional response only.

The bigger question is what emotions even are. If it's a chemical or biological reaction then it'd be weird if other mammals didn't have about the same emotions as humans.

It's difficult to see how an animal feels unless you know it well. I can mostly see how my own dog is doing, but I have no idea what mood a random dog on the street is in.

You know that feeling you get when you look into your dog's eyes? The same parts of your dog's brain became active, so they're probably feeling similar emotions at that moment.

Neurobiologically they absolutely do. Most animals have amygdala, for starters, so they feel a lot of basic emotions. As for love, one would only need to ask whether they can do things such as produce oxytocin, recognize faces or voices, desire touch, etc.

Yes. We had a cat that'd sit with us when we weren't feeling well. If you were lying in bed with a migraine he'd snuggle in and rest his chin on your forehead. He could tell when we were ill and would always settle in with us including missing mealtime.

I don't know about smiling but cats and dogs absolutely feel emotion and affection.

I don't think I've ever seen dogs, cats and other domestic animals smile because they're happy and show love to their owners for treating them right.

My dog "smarls" (smile+snarl) at me when I come home. We've taken a still photo of him while smarling and it looks horrifically vicious. It's like a stock photo captioned "aggressive dog". But he's actually happy. The difference is body movement. An aggressive or dangerous dog will be very still, just showing teeth, usually growling and backs away from a threat or quickly lunge if it gets too close. A smarl is usually accompanied by a wagging tail and body wiggles and slowly approaching to get pet.

You may be interested in a paper Thomas Negal wrote about 50 years ago called "What is it like to be a bat?"

https://www.sas.upenn.edu/~cavitch/pdf-library/Nagel_Bat.pdf

It's not just about emotional states, which we can observe the behavioral states of but don't know what it is like to experience as other animals. It's about experience and consciousness which I think speaks to the underlying question of when other animals experience an emotional state if we can relate it to our own phenomenology for similar appearing states.

With cats and dogs it’s all about the tail from what I’ve observed. They can’t really smile but their wag (dogs) or tail position (cats) convey their feelings. If your cat’s tail sticks straight up when they see you you know they have an affection towards you. Or maybe it’s food. All I know is straight up tail is a happy cat.

If it’s swishing, look out. And a dogs tail stops wagging and goes into like a prone state when they are concerned.

My dog definitely loves me. I feel the love every day from her. I can feel it in my bones. That animal loves and trusts me.

Others have cited sources but yes, dogs and cats definitely feel love.

There is a whole book about this, "Dogs Never Lie About Love", by Jeffrey Masson.

Yes, but not necessarily the same way we experience them. Dogs and cats don't have the facial muscles to smile even if they wanted to and show pleasure in other ways.

Some do and some don't. Depends on the individual, like with people.

I actually knew a dog whose owner taught him how to smile. He'd come running up to you to greet you at the park with his teeth bared in a friendly way.