Do STEM professors retire from research at age 65, while continuing to teach classes? I see many STEM professors work well into their 70s, 80s, and sometimes even into their early 90s - mostly in teaching, but their research careers were outstanding.  One of them that I spoke with told me that he hasn't done research in many years - though he teaches a class every semester.  

Do STEM professors "retire" from research at age 65, while continuing to teach and enjoy their tenure?  Or are many professors still active in research past retirement age?

I'm asking primarily about US universities.
This is very much a function of the regulations of the institution in question, and the health and desires of the faculty members in question.

I have known a number of faculty members who start to wind down their research groups at age 65 or even a little earlier, while others wait until about age 70. I also know of schools that don't allow faculty members over 65 or 70 to bring on new students, thereby effectively "shutting down" the groups. But I do know a handful of faculty members who were active as researchers into their 70's and even into their 80's.

In countries other than the US, policies are much stricter. In Germany, for instance, professors must retire at 65 unless their successor allows them to continue to supervise students and conduct research.