Does a swarm damage other swarms or creatures of the same kind?

Question

I am wondering if swarms damage other swarms of the same kind if they occupy the same square, or other animals of the same species/kind that move through, or even join them.

An extended example shows the problem:

A 6th level druid uses his Wild Shape spell and turns into a tiny bat (animal). Then he casts one Summon Swarm of Bats inside a globin's square, 30 feet from him. Then he casts another on his next turn, in the same square.

Does one Bats Swarm damage the other? Why or why not?

After the goblin is killed by the swarms, the druid stops his concentration and moves into the square of the swarms as a bat.

Is the druid in Bat Form damaged by the Bat Swarm? Why or why not?

Answer 1

Whether or not 2 'natural' swarms of bats would hurt each other I don't know, but multiple Summon Swarm spells would.

The spell states:

You summon a swarm of [bats] which attacks all other creatures within its area... the swarm attacks or pursues the nearest creature as best it can. The caster has no control over its target or direction of travel

A swarm counts "as a single creature", even a summoned swarm, so, assuming there are no other living creatures around, 2 swarms would go after each other. RAW they would do their normal damage to each other, although I would rule they do more, since the constituent creatures of each swarm can reach each other.

The swarm (or swarms) would also damage the Wild Shaped druid, as the druid is inarguably a distinct living creature, even if it is shaped as a bat. If the 2 swarms started attacking each other, and then the druid moved into them, he would be attacked by both swarms at once.