If your looking at a major based on the careers oppuntitunes, take a look at
U.S. Department of Labor
Bureau of Labor Statistics
Occupational Outlook Handbook
Some info on Mathematicians:
A Ph.D. degree in mathematics usually is the minimum educational requirement, except in the Federal Government.
The number of jobs with the title “mathematician” is declining as the workforce becomes increasingly specialized; competition will be keen for the limited number of available jobs.
Master’s and Ph.D. degree holders with a strong background in mathematics and a related field, such as computer science or engineering, should have better employment opportunities in related occupations.
Mathematicians should have substantial knowledge of computer programming, because most complex mathematical computation and much mathematical modeling are done on a computer.
Mathemeticans:
http://www.bls.gov/oco/ocos043.htm Professional and related occupations
http://www.bls.gov/oco/oco1002.htm has the following subcatergories directly related to science.
Life scientists
Agricultural and food scientists
Biological scientists
Conservation scientists and foresters
Medical scientists
Physical scientists
Atmospheric scientists
Chemists and materials scientists
Environmental scientists and hydrologists
Geoscientists
Physicists and astronomers
Social scientists and related occupations
Economists
Market and survey researchers
Psychologists
Urban and regional planners
Social scientists, other