A Frenchman and a Japanese - who's the monkey and who's the pig?

As the problem with the machine development project I talked about recently (post here if you're too lazy to scroll down a little bit) is deepening I have found myself more and more dragged into trying to coordinate things between the Japanese team and some of the experts in our different R&D centers.

One of the key experts in the specific problem is located in our facility in France and in a discussion with the R&D global project leader in Germany we talked about possibly teaming the French expert up with Mr. Pot-Belly to try and work something out. Now, it should be worth to mention that although the Frenchman is very competent in this specific area, he is quite difficult to deal with and is not particularly great at English. Similarly, Mr. Pot-Belly is also a bit of a character and similarly not that great at English either to begin with, but the project leader have worked with them both separately quite extensively and know them quite well so as we discussed the possibility of having them work together, the project leader sighed and said "Well, having those two working together without adult supervision would be a bit like putting a monkey and a pig on running a nuclear plant, I wouldn't be able to sleep at night, so I guess I will supervise their work personally".

I really liked the metaphor, but after we hung up I started thinking about who would've been the pig and who would've been the monkey? Something to dig deeper into at some later point!

(Disclaimer: Do not get too excited, I know the project leader very well and the comment was not a racist comment, but based on knowing their individual pecularities and considering the potentially explosive mix in having two very interesting characters working together for the first time with significant communication difficulties)