Astral traveling was first discovered by ancient Indians of North America. They were shamans and native tribal healers. They would sometimes inhale some form of herbs to give them an out-of-body experience. In their out-of-body experience, they could transform to whatever beast or fowl of the air as they wish. Common forms were werewolf, bear, eagle and falcon. That is why they thought that these animals were their guardian spirits.I have not heard of any healers transform themselves as fish or whales though I do not discount these possibilities. As time went by, these sacred traditions were kept only to their own chosen people.
As for modern day astral traveling, anyone could just do it, provided they have proper guidance from a teacher. Today, astral traveling has many names. Some call it soul traveling, psycho navigation and quantum travel. They are all basically astral traveling.
Is it dangerous to travel by yourself? I subscribe to the idea "No". There are some rumors that if you travel too far (or too long) or your body is hidden by your friends, you would not be able to come back and your physical body would eventually die. Aside from that, I heard about one case in Penang Island though it is not substantiated. The practitioner died for no obvious reasons.
We all travel every night and it is very safe. There is a silver cord that always links us to our physical body. It cannot be cut or damaged by any means. We have 7 billion people on earth and all travel out of their bodies, some in dream states and others according to their fantasies. Of course, there are people who die naturally in their sleep but I don't believe it is because of astral traveling. Do we encounter astral beings in our journeys? Yes, we do. That is why there is always a guide that goes with us. Whether we are aware of the guide or not, they are with us all the time.
Astral beings or astral entities are in the same categories as the beings on earth (such as the fairies, pixies, etc.) and below the earth (such as the dwarfs and leprechauns). Astral beings belong in-between planets and stars. They are part of the Celestial Kingdom. Just like us humans, where we have naughty and mischievous ones, they too have the same. In fact, in the Celestial Kingdom, there are beings who are naughty, mischievous, dangerous, angry and friendly.
In the Celestial Kingdom, we have Minotaurs, Centaurs, Satyrs, Unicorn, Dwarves, Leprechauns, Pixies, Fairies, Astral beings and much more. All of them have their unique behaviors. Some, like I said, are friendly, others are angry, hostile and can be deadly. Most can be helpful, especially the Astral beings but at times they can be mischievous too. Should you encounter them you will know their characteristics. I have encountered astral beings that can take on a form where you may feel comfortable and can have a rapport with them.
Naughty or mischievous ones can sometimes masquerade as your departed loved ones or the guy or girl of your deepest fantasies. But, by just wisely questioning them, if they don't know the answer they would immediately fade away. Your guide is actually your guardian assigned to you since you were born. The guardian will actually evolve with your awareness. If you are unaware, neither is your guardian.
The Celestial beings of the higher order seem like both female and male gender but they do not have a gender. They are just beings, no marriages or reproduction of offsprings. Their sole purpose is to serve the highest order.
The pictures below are artists' interpretation of some of the astral beings.