With hunting being so costly to the velvet worm, it comes as little surprise that some species choose to not go hunting alone. One Australian species- Euperipatoides rowelli- has been shown to form packs, with social hierarchy, pack protection, and team hunting. These packs have an ‘alpha female’, which usually is selected by being the largest and most aggressive individual in a group.

The velvet worms form a clump, and the largest female makes her way to the top, biting and pushing the others as she does. In this way, the velvet worms not only form a tolerance to being close to one another, but also an understanding of who is – both literally and figuratively – at the top of the pack.

The pack hunts together, trapping larger prey through using multiple slime jets. The alpha female will then, much like a male lion in a pack, push the other members aside to have their feed, after which the others will join in on the feast.

http://www.eartharchives.org/articles/velvet-worms-the-voracious-snipers-of-the-undergrowth/