True enough, but in those species males are typically larger to begin with, where in garters females average three times heavier than their male counterparts. For the males to catch up to their weight in 8 weeks is pretty impressive.

-It would have been neat to see a measure of activity...did they gain so much weight because they became less active after castration?
-A measure of fat levels...is the added weight of the males a similar ratio to females, or are these obese?
-Additionally it would have been interesting to see a measure of energy effcientcy. Its theorized the females grow larger in size to be able to more suitable to carry greater quantity of offspring, but males can stay small because they don't need to be big, so why waste the energy?