Ok, I was going to do my headcanons in order of favorites but I messed up. This. THIS is my favorite.

Andalites are not only a social animal but naturally gifted in telepathy.

In the days before civilization a herd of andalites could take flight at the drop of a pin. This panic could be detrimental to the herd if not managed correctly. Some andalites, Shepherds (in english I guess), have a progressed telepathy that can direct and control the herd in varying degrees.
Think of collies herding sheep, they were most effective flanking the herd, capturing their fellow andalites in their field of telepathy to calm, steer or inflight the herd. The more powerful ones can clamp down and temporarily steer or change emotions completely of an individual, mostly however they can only nudge slightly to steer in their preferred direction.

This power in modern andalite civilization is considered a myth.

BUT HOLD THE FUCK ON.

Remember that philanthropist family I mentioned a while ago?

How they steer modern civilization in the right direction to benefit the herd?
Yes, they are genetically predisposed to this power, many of the family members are shepherds and its more prevalent in females.
Pictured above are the twin daughters of the head of the family, each moderator gifted in teleherding but being so similar to each other the wave lengths are amplified greatly when used together.

*BOWS THE FUCK OUT*