Quote - Maya - No native linux support.

Maya does support Linux natively.  Look here.  We've recently moved our animation and rigging departments to Maya seats, on Linux - Fedora.  There are no plans to do this with our modeling and texturing seats.

ILM and Dreamworks are two of the most noteable studios employing literally hundreds of Linux workstations, and renderfarms, with deep proprietary applications, as well as commercially available products.  The very best proprietary software is traditionally built on top of open-source software.  This, however, shouldn't be considered the industry standard.  Not every studio in the industry utilize proprietary software, and commercially-available packages do have a long, prolific lineage in the motion picture FX industry.

I don't have hard numbers, but if I were to speculate, based on the information I have seen, I would say the majority of studios are still using Windows or Mac for the largest number of seats. 

Autodesk once released information suggesting 3dsmax was the 3D software package with the largest registered user base of the "big 3".  This was about 7 or 8 years ago, but I imagine it is still the case today, and as previously mentioned, it is only available for Windows. I have seen 3dsmax hosted in Wine and Ubuntu, but not in a production environment.  This would seem to indicate that there are a great deal of professional studios, particularly in the gaming and architectural CG communities,  running on Windows-based seats.

- Daniel Kramer
Modeling Supervisor/Senior 3D Generalist
Intrigue Studios, EncoreFX