4 year old discovering himself

I am raising my 4 yr old grandson & lately he has been doing alot of things that I dont know if it's normal at his age.. He has discovered his private parts & the other day he was in the yard standing by the pool & he pulled his pants down & started to pee into the pool & thought nothing of it.. He has also discovered womens breast,, my ex husband had a magazine in his bathroom & my grandson found it & was looking at it,, now he is lookin down the front of my friends shirt... My biggest concern is he was playing with his toy animals the other day & took one of the & tried to stick something in its butt,, he watch's alot of animal planet & dont know if he seen it on there or what...
The actions that he is doing are they normal for a boy his age,, I raised 2 girls so I have no idea about boys...

[margypops]

The pants down peeing is very normal so dont concern about it However your ex husband should not have books whre a small child can see them ,ask him to remove them.when the child is around.If he is starting to do more inappropiate behavior you need to be watchful as it is very often learned and copied behavior check out who is alone with him and be observant and protect him .

[mbransch]

I am a mother of 4 boys - my oldest is 5.  This is call the Phallic stage according to Freud.  Look it up it is quite interesting.  This is when boys discover themselves and the difference between body parts. I think that it is best to talk to them and explain the difference with out going in to any sexual detail.  My son used to determine boys and girls by Tarzan the disney movie - boys had nipples and girls had breast.  Make sure that if he is touching himself in self discovery, that you explain good hygiene.  He could get an urinary infection. Peeing outside is normal, explain to him that bathroom time should be private and that we should not show strangers out private parts.  

To make you feel better my boys are always talking about thier pee pees, even the twins touch each others privates in the tub. They are just curious.