Questions on the five Skandhas I find that the five Skandhas can be very confusing at times, as the Western idea of mind and perception is very different to the Buddhist idea of mind and perception. On top of that, many explanations of the five Skandhas online seem vague and sometimes seem to be interpreted differently, depending on where you go.
The first Skandha: Form
Does this refer to physical form? Can we only know form through the sense organs?
The second Skandha: Sensation
Are these just sensations from the sense organs?
One description online describes sensation as follows:

... it is the sensation experienced through the contact of eye with
visible form, ear with sound, nose with odor, tongue with taste, body
with tangible things, mind (manas) with ideas or thoughts.

If this is the case, does emotion fall under sensation?
The third Skandha: Perception
A description I found:

Samjna is the faculty that recognizes. Most of what we call thinking fits into the aggregate of samjna.
The word &quot;samjna&quot; means &quot;knowledge that puts together.&quot; It is the
capacity to conceptualize and recognize things by associating them
with other things. For example, we recognize shoes as shoes because we
associate them with our previous experience with shoes.

My understanding is that the faculty to recognize is consciousness. However, consciousness is said to be a different Skandha. My understanding is that consciousness is that which perceives the world around it. More broadly, how is perception and consciousness different?
The fourth Skandha: Mental Formation
A description I found:

This aggregate includes all mental factors except feeling and
perception, which are two of the possible fifty-two mental factors
noted in Buddhism.

I'm assuming this is where emotions exist? Is happiness an emotion? Is loving-kindness an emotion? If not, were do they exist, in terms of the Skandhas?
The fifth Skandha: Consciousness
A description I found:

Vijnana is a reaction that has one of the six faculties as its basis and one of the six corresponding phenomena as its object. For example, aural consciousness -- hearing -- has the ear as its basis and a sound as its object. Mental consciousness has the mind (manas) as its basis and an idea or thought as its object.

If this is the case, then is consciousness that which observes sensations, mental formations, perception and form, or that which experiences sensation, perception, mental formations and form? Can the experience of sensation exist if we are not conscious of it? Are animals conscious? Maybe a more important question is: what is the difference between consciousness and self-awareness, in the Buddhist context?
I realize there are a lot of questions here, so thank you to whoever takes the time out of their day to answer them. Have a good day!
Comment: This is a very cogent, very important, even fundamental issue in the process of direct inquiry. The last question haunts me: what is the true definition of consciousness when referred to as a Buddhist skanda? Specifically, self reflexive awareness--for lack of a better term--seems fundamental, even unitary. Vedantic teachings inevitably lead to the direct discovery that &quot;consciousness is all&quot;. Consider Turyia. The Tibetan term, Rigpa, seems to point to the same realization.
Rupa


  Does this refer to physical form? 


Yes, anything physical is included in this category. Ex: light, sound, aromas,earth element, water element, heat element, air element  etc. 
However, with regards to the five skandhas, a thought is also called a rupa when it becomes the object received by the mind sense faculty. Ex: a memory


  Can we only know form through the sense organs?


Yes, there'll be no knowing without the 6 senses.

Vedana


  Are these just sensations from the sense organs?


Sense organs cannot produce sensation by themselves. The contact should occur. That is the union of Rupa, sense organ and the relevant consciousness.
ex: light, eye and the eye consciousness 

There are basically 3 kinds of sensations: pleasant, painful and neutral.


  If this is the case, does emotion fall under sensation?


No, that is Sankhara(Mental Formation).

Sanna(Perception)


  My understanding is that the faculty to recognize is consciousness


No. Consciousness is just base awareness.


  how is perception and consciousness different?


Sanna(perception) is what recognizes the object specifically. Awareness cannot tell what it is. But awareness is present at this stage as they all rise together. 

Sankhara(Mental Formation)


  I'm assuming this is where emotions exist? Is happiness an emotion? Is
  loving-kindness an emotion?


Yes, that's right. Happiness, loving kindness, hatred, jealousy, craving etc. belong to this group

Vinnana(Consciousness)


  If this is the case, then is consciousness that which observes
  sensations, mental formations, perception and form, or that which
  experiences sensation, perception, mental formations and form?


A single experience contains all 5 of the Skhandas. They make up the whole experience. Think of it as drinking a chocolate milk shake. When you drink it, do you feel the taste of milk, chocolate, sugar separately? No. You feel them all together. Consciousness is like the water they are all mixed in. Consciousness cannot separately observe anything. Observing itself is an experience where all 5 skandhas are present.  In an experience, consciousness simply plays the role of being aware. When you are asleep, the ear consciousness may not be present at the ears. That's why you won't be able to hear, even if the sound hits the ears.


  Can the experience of sensation exist if we are not conscious of it?


No. Every experience has all the 5 skhandas. 


  Are animals conscious?


Yes, they are beings. It's Panchaskhandha for them as well


  what is the difference between consciousness and self-awareness?


Consciousness is what plays the role of being aware in an experience. Self-awareness is an experience(5 skandhas) in which the perception identifies the object of the experience as a self.   

To give a common example to illustrate the functions of the Skandhas, say you are smelling something delicious. The smell and the nose here are Rupa. When they get together with the nose consciousness, contact happens. At that moment the Vinnana is aware that an object is present at the nose sense door. Vedana tells that it is pleasant. Sanna tells what it is: whether it's a pudding, cake, ice cream etc. Sankhara tells it's good and desires for it. Keep in mind that the event of smelling here involves many instances of five aggregates rising and passing away.