Some cactus protect the growing tip of the plant with a mass of spines that looks somewhat like hair. I can assure you, you would not like to run your fingers through this cactus' mass of spines. Not only do the spines protect the growing tip from mammals, birds and insects, but they provide valuable shade in areas where there is no other plant cover. This type of growth is associated mainly with columnar cactus that grow to be 20 to 30 feet high. This type of spinal growth is commonly seen on Senita cactus.