Xenobiologist
From StarFleet Bureau of Information
Xenobiologist
Xenobiology (also called astrobiology or exobiology) is the biological science concerned with living alien organisms. Xenobiology was also a course taught at Starfleet Academy.
A biologist who specializes in the field of xenobiology is referred to as an xenobiologist, exobiologist, or astrobiologist.
The sub-discipline known as comparative xenobiology is the scientific study of the physiological features of various alien lifeforms.