Do you think some of this is instinct and some of it is learned?

I was a PE teacher today. The teacher had them playing a pretty cool game that required cooperation and problem solving. It was “Crossing the river.” Think, “The floor is lava!”
There were 4 mats stretched across the center of the gym. Each mat had 1 scooter on it and a long rope that would reach from the mats to the far end of the other side.
The kids were broken up into 4 teams. I guess the other day the teacher assigned teams because for the most part it was 2 teams of girls and 2 teams of boys.
Next I gave them these round rubber plastic discs, 2 sizes, roughly the size of a small and a medium pizza. There was 1 disc per person. The first person in the team started by dropping discs in front of themselves and jumping to the next disc, then dropping another disc, which was passed from the back to the front (DO NOT THROW THE DISCS!!) eventually the whole line was out in the middle of the “river” slowly advancing by passing the last disc to the front.
The kicker is, in order to do this at some point people found themselves having to share one of these small discs with another person until the last disc got passed up to the front.
Then they get to the mat, and had to figure out how to cross the river on this scooter boat and THEN get the boat back to the island for the next person without going back in the river. Can’t walk on the water! If you fell off at any point your whole team had to start over. They got super creative with the rope. One class I was very, VERY impressed with because one team tried to just shove it back over without the rope, and it landed in enemy territory….and the enemy passed it on. They didn’t have to, but they did. Kudos.

Who ever got all their people to the other side of the gym “wins.”

Invariably the girls made it first because they cooperated. The boys just got lost in shoving each other off the pads and fighting and all that bullshit (DO NOT THROW THE DISCS!!”) which meant their team kept having to start over.
Finally the teams got exasperated enough with starting over to start cooperating, but they never were as good as the girls. With the girls, at one point,one of the girls was losing her balance on the pad and in desperation she just LEAPT into the air…and one of her team mates caught her! I never laughed so hard.

So, why were the boys so ready to fight and the girls so ready to cooperate? Nature or nurture?