Soft spines tend to take the form of bristles or hairs instead of thorns, spines, spikes, quills, prongs, or needles. Both bristles and hairs may have softer, gentler forms. But bristles tend to be much shorter than hairs.

Or bristles and hairs may not be sharp, but still irritating. An example of a softer, gentler haired cactus is the old man [Cephalocereus spp]. Its long, silky hairs may end up encasing much of the blue green columnar stem in a soft, white beard. An example of the soft and the sharp of cactus spines is found in another old man cactus [Oreocereus spp]. The stem is encased in a soft down of fine, long, white hairs. But underneath are razor sharp yellow, white or red needles.