It's best to understand a woman's nature/behavior first in order to understand why they "bicker" or "badmouth" each other.

Women will always seek the better provider in their lives. In order to get this "provider" they need to make themselves attractive to him. A woman bases her attractiveness, or self-worth, on how good she physically looks to a male (a male bases his self-worth on his confidence and how well he can provide for a female). A woman wants to make herself as pretty as possible, and make herself the center of attention so there are a lot of details they go over themselves with and thus, they are very critical of themselves. This attention to detail is also directed at other women, and so they nitpick at each others' appearance in their minds, making not of and possibly pointing out any flaws.

We all know women compete with each other for men (I don't know if it's the same for other women's attention), so they try to make themselves better than the other. Some women go to the extreme by making other women look or seem less attractive to a male. In sense, it could be best described as sabotaging. This where all the made-up stories, lies, gossip-spreading and getting in each others way comes in. It is these battles that manifest the bickering and bad-mouthing; and why "women hate each other". As Light Knight put it, it's about trying to be more socially acceptable. But, there's a little more to it than that; it's also about being the only person anybody will ever care to notice as much as possible while crushing any potential competition

That's the gist of it. And yes, there are exceptions to everything. Not all women bicker because of competition. There are other dilemmas, such as a woman being a total b***h to another women. And what I described is more of an extreme case. I think most women, older women, are a bit more passive about doing that stuff. Older teen girls, in my opinion are the extremists.

I'm no girl, so correct me if I'm wrong any of this.

Personally if I'm bad mouthing someone, it's for a reason, it doesn't matter to me what their gender is.

I don't have any female friends who do this. If they DO occasionally insult anyone, it's for a reason.

If a woman is constantly gossiping, judging other people, or being negative in general... Well, they obviously she has issues, and I don't want to be her friend or acquaintance. I guess I just totally avoid people like that.

It's all in insecurity but not always jealousy there is a big difference. Most the things women bad mouth about another woman our actually their own flaws that they aren't willing to deal with.  Also if a girl doesn't feel good enough sometimes it feels easier to talk badly about another girl and make her look better in comparison then to actually better herself. Another reason is if there is a person that they care about in their life that hurts them in anyway but they are afraid to let them know it's easier to take it out on someone else. 

I have absolutely no idea why girls would badmouth each other. I'm a girl, but I never badmouth someone at all. It could be because some girls worry about many things I don't worry about.  It could also be for insecurity or jealousy. Those are just some thoughts I have though.

   I know the answer to the title of the thread. I have a pair of Sisters. Normally, they gang up on my and have their own conversations. I wish I could trade them for better things. I often see hear them screaming at each other like 1:30 AM. They are racist, especially at their own race.

i do see it all the time, its because they are girls  LOL,

I think a friend of mine once said "a guy might hit you or break a few of your bones but girls will destroy you emotionally", I guess it is because females are less likely (although increasingly likely) to engage in a physical confrontation so use verbal insults to settle their deputes.
I am just glad my psychology class is civil because I am the only guy in a class of about 8.

I've never been the type of girl that does this but a lot of my so called friend's were.. they loved doing this to other girls.. idk if it's just something they like to do or if they feel bad on the inside.. I also didn't like how there were so called clicks and if your friend in that click didn't like another girl you couldn't like her either.. I never hung out in those groups.. it was kind of a down rated version of mean girls.. I will never understand it but most girls just do this.. I see it almost all the time and I don't say anything anymore because I don't want to fall victim to them.. so I stay away and in my own space.

Thank goodness that I am not part of the badmouthed girls because it's just a waste of energy and time to badmouth one another. There are better things to focus on than fighting and arguing.

I'm guessing girls badmouth one another is due to insecurities or to increase their popularity in order to feel good about themselves. It's all about who is the "best" in the surrounding environment so it's pretty much like a competitive state of mind but in a downgrading sense. Girls are more emotional so their voices and minds are their weapons like how boys use their strength in order to settle situations.

Also, it seems that girls in general like drama or gossip to make their lives much more interesting and entertaining for some odd reason but I can't really figure that out even though I'm a girl myself.

They should really stop badmouthing to each other because someone will always get hurt especially emotionally but life is always repeating itself.

WHY CAN'T WE ALL GET ALONG?

Well I don't think this is a phenomena that is just attributed as women, in fact, I think guys badmouth each other just as much as women.

Men however tend to do it face to face(which can and typically ends violently), while women more usually do it behind the back(of course not all the time). It's sort of our unfortunate human nature to want to be negative towards other people. Men and women share this tendency, but do it different ways, and it's usually not productive.

Why can't we all just be friends?

Okay man, I'll tell you why I think girls badmouth.

1. One of the girls has a crush on the other girl's boyfriend. (eg. Samantha told Brad that Sam cheated on him) something along those lines.

2. They just hate each other (case closed) Girls always badmouth girls they hate.

and not all girls mad mouth people (eg. Me, I think its rude to talk about someone behind their back)

hope this told you what you wanted know.

I dislike a lot of girls because of things like this, which I guess makes me part of the problem. If a girl is really mouthy and obnoxious, I'll probably tell a friend of mine that I feel that way, but usually it's out of curiosity to see if they feel the same and see the same issues, or if it's just me being an ass. Guys keep snarky things to themselves a lot more than girls and it makes them more enjoyable to be around, since they're not so fickle and insincere. I just feel like girls have a lot more characteristics worth madmouthing, haha. Luckily there are plenty of cool chicks and that's all good and well, but I'm talking about the seemingly stereotypical general females that tend to pop up.

However, I will say I've been friends with plenty of dudes that can throw down a person, male or female, just as well as the cattiest of females. It's not always a gender thing and is often just a personality thing. Females just seem a lot more outward about it.

I think it's because they're so sensitive. Us guys fight too but like after a day or two... We make up and just be pals once more. To the girls on the other hand, once they fight, takes weeks, months, even years. Just in their nature I guess