I don't think that there is such a thing as "White Elk". The Roosevelt elk are the biggest, alot of times over 1,000 lbs.

Rocky Mountain elk are the most common, and they usually weigh under 1,000 lbs, around 700.

Tule elk, are notably smaller than either of the predecing, and are the least common. They have small herds, and are VERY expensive to hunt.

I think the Manitobian elk went extinct awhile ago. They say they inter-bred with Rocky Mountain elk and Roosevelt elk.