In Season One of the most recent cartoon of Teenage Mutant Ninja Turtles, the four brothers get along like normal siblings would, which is to say: not as well as they could. All four are proud of their individual talents, but more than that, they rely on them. It is difficult for the four of the, to work as a team at first, and they also have trouble listening to one another. Leo and Raph have odd ways of showing their love both to one another and to their younger siblings, and even Mikey and Donnie have trouble getting along. Donnie and Raph are almost always going after the other’s faults, and Raph and Leo are almost always at each other’s throats. Mikey is incredibly immature, which the rest of team has trouble accepting.
By the end of Season Two, it’s obvious that they all care about one another, though they still tease often. Raph will push the others hard, especially if they’re hurt, in order to help them be the best they can be. Donnie makes sure the others are always healthy or healing, even if he still argues with Mikey and Raph. Leo refuses to give up on his family and will protect them no matter what, even if he’s injured. Mikey shows his affection for the others by hugging them tightly (even if they’re injured) and attempting to cheer them up if they’re upset.
After the vision quest that marks the start of Season Three, the four turtles mature greatly. Mikey becomes solemn and focused. Donnie begins to rely more on his body than his brains. Raph learns to use his anger as a precise weapon rather than a random explosion. Leo becomes more aware of himself as he learns not to let anything make him doubt himself. As they return back home, they are better able to work as a team.
In Season Four, the entire family is very protective of one another. They’re not afraid to fight for one another, and even Raph shows how much he cares for the others. They continue to be able to work well together, and they listen to one another.