Hi hv, sorry for all the hair questions, it just occured to me, all the wild animals don't have access to shampoo, so how come their hair isn't overflowing with oil like our hair would do if we didn't shampoo it all the time, I mean, they can just bathe in water and they look great, how come we can't do that, what makes hair so oily?

We have sebaceous glands at our hair roots that produce sebum that makes our hair oily.  All animals though do not contain oil glands.

If we didn't use shampoo at all would our hair stop being so oily and be okay with just water-rinsing?

The water alone will not remove the oil.  The soap acts as a surfactant to help remove the oil.  Or you would have to use an absorbant such as a finely powdered clay, or a starch that you apply and let absorb the oil then brush out.

EDIT- I found this, which says our hair produces way too much oil because we keep shampooing our hair, makes sense

http://www.instructables.com/id/How-to-Go-No-Poo/

If we over dry our scalp with soaps the body will try to compensate by producing excess oil.  One way to help counter this is to use less shampoo.  A lot of people use so much shampoo that they can make a beehive hairdoo with all the lather.  This will definitely strip all the oils from the hair and scalp. If they reduce the amount of shampoo they can get rid of most of the oil and leave a little for the hair.

Another option is to brush a few drops of jojaba oil (technically a liquid wax) in to the hair after washing the hair.  Jojoba oil is very similar in structure to our natural sebum.

so they advocate not using shampoo, pretty hard idea to compensate, how am I going to get nasty things out -.-

A couple of suggestions above.  There are "dry" shampoos you can make or buy that work on the same principle as the absorbants I mentioned above.

but more importantly, they reccomend baking soda to remove grease, which I dont like because it would remove the acid mantle, so two questions hv,

does hot wait remove the acid mantle?

The water will not neutralize the acid unless it is hard water.  Soaps will make the scalp alkaline though unless pH adjusted.

is there any acidic 'shampoo' that would remove excess oil while one transitions to a no-shampoo lifestyle, so you dont have to use baking soda, then acidic product, etc?

You can pH adjust your shampoo by adding a little powdered citric acid then shaking it up well.  Or you can make an acidic solution to spray on your hair and brush in after washing your hair and towel drying it.

Keeping  hormones in check will also help to prevent over production of sebum.  For this I recommend the bitters, B vitamins and zinc.