Are managers mentors?

A few months ago I had lunch with someone writing their Masters on the merits of business managers taking on mentoring roles. After we met they sent me an article (naturally now that I want it, I can't find it anywhere) reporting on the benefits managers receive from being a mentor for others. It made for interesting reading, especially because I'd never considered that the mentor would actually gain anything from the process.

The research basically said that senior managers often felt less stressed and more able to face complicated decisions after having a meeting with the person they were mentoring as a result of having spent time investing in someone else's life and development.

It also made me start thinking about what criteria make up a successful mentor. Definitely the criteria will change at least a bit across purposes, people and contexts, but surely there are some commonalities too. There is a bunch of academic research and pop-literature on the topic of mentors especially in relation to professional development, but I have some ideas of my own too.

• A mentor should be able to act like an editor - constructively question and criticise elements of the mentee's development, behaviour and attitudes.
• A mentor should be able to cast vision and act as a 'thought-planter'.
• A mentor should be able to set pace, but also adapt their agenda and style to meet the feedback from the mentee.

So even though a mentor-mentee relationship is usually one on one, now that I've written that list out, remind me again how mentors are different from leaders?