Human newborns are the only mammals that do not stand up soon after they are born. Elephants, giraffes, and horses take a few steps just a few minutes after they are born. Before a human newborn does anything similar it will take about a year and during that time it will roll and drag itself on the ground. Studies tell us that with our mouth and nose just a few centimeters from the ground or mat the infant inhales an invisible cloud of dust, spores, fungi and biological matter. As if this were not enough, the various filters (cough, sneezes etc.) which are well developed in an adult are much less so in an infant. So, the cloud of filth that the infant inhales with its nose against the floor is up to 20 times the concentration of filth that an adult breathes. Maybe crawling on the floor is nature’s plan to help us. It appears that those infants who crawled on mats that were never cleaned, once grown up never need to visit an allergy specialist and so they save on very expensive allergy testing with the relative treatment. They immunize themselves against dust mite, pollen and various animals at home on their own.