How and why do bees make their hives like this and not round?

The cross-section of the honeycomb is hexagonal, essentially. It’s because it is the only natural grid where the adjacent cells are all equidistant, in 2D geometry. The honey cells are round (cylindrical) and staggered (which is better structurally than a square grid) and the hexagonal honeycomb between them is just the natural shape that results in geometrically.

However, how insects make their hives is a complete mystery to conventional science. No one knows how hundreds or thousands of individuals with speck-sized brains can possibly coordinate to make (or repair) a complex structure like that. No one really understands many large-scale coordination like that, even the growth of an animal or plant body from cells all with the same DNA. There is no physical science explanation possible, really. We just know that groups of cells or insects or birds or whatever seem to have some features of group organization and shared consciousness, or just plan or hologram or something.

Creating circles is natural. If you just used circles, you would have each circle surrounded by six others. The problem with this arrangement is that there is wasted space between circles. The next step would be to flatten the circles into hexagons to capture the spaces between the circles. Article

@LostInParadise I’m glad bees have discussed this and worked out the proper arrangement or they might have been stuck with circles to work with.

The transition from 6 circles surrounding a circle to a hexagon is not all that great. I am no evolutionary biologist but it does not seem to be out of the scope of evolution. Bees exhibit some rather sophisticated behavior, like doing waggle dances telling the direction and distance of a bunch of flowers. If evolution could do that, it is not hard to imagine it getting the bees to flatten the connections between circles.

Something else to consider is that the structural strength of the circular structure is not all that great. The circles theoretically touch each other at just a single point. In reality this would be larger, but not nearly as good as the length of a side of a hexagon.

It’s pretty clear that none of the insect architecture can be explained by just DNA / evolution / mechanics / dancing, though those are there. There is some un-understood sort of group / species intelligence and consciousness at work.

I tried to visualize how to get from circles to hexagons and, not being very good at visualization, I created this drawing Notice how easy it is to get from circles to hexagons. If you put in lines tangent to the circles where the circles touch, the lines intersect at the corners of the hexagons. If the bees in adjacent cells simultaneously squish the circular cells together, it is not hard to imagine that they will end up with hexagons. I think it is neat how the regions between the circles divide into 3 pieces of the same size and shape that connect to the circles to form the hexagons.