Illness/Sickness: Red efts have they own little friend clicks?

[EarthLover93]

So Im raising 4 Red efts. I had caught these wild and decided to raise them for a bit. They all eat well, walk around and do newt stuff pretty normal. However at first i had 3. Then i found my 4th, which is the largest. After i added the fourth i noticed that one of the first 3 and the larger 4th always stay together. They always are laying right on each other. The other two do not. They just do their own thing and usually do not lay together. But the other 2 Always do.
Whats the reason for this. Im just wondering what they are doing/ thinking