Life and work
Thomas worked at the Natural History Museum in the field of mammals, of which he described about 2000 species and subspecies for the first time.
He began in 1876 to work at the museum and changed in 1878 in the Zoological Department. In 1891 he married a wealthy heiress. Their funds made it possible for Thomas, for the museum to acquire a large number of mammalian collecting pieces, which he described one by one.