harry potter - How did the basilisk get enough food?

This is related to How did the Basilisk survive for a thousand years? The basilisk in "Chamber of Secrets" is shown to eat small mammals and reptiles, from the skeletons that are discovered. I understand that snakes that don't get enough food stay small, and one way to get a bigger snake is to feed it more. The basilisk must start small, as it hatches from a cockerel's egg.

If it was eating stray familiars, in quantities required to grow as big as it did, why didn't anyone notice? At the very least, wouldn't older students mention that animals had a tendency to vanish so either bring a cage or don't get too attached? (How did Neville's toad, Trevor, keep coming back?)

I understand that real snakes actually digest the bones of animals too, so perhaps the digestion of a basilisk is different enough that it spits out/excretes the skeletons? Would this be enough of a difference to explain how it uses less of the available food source but grows bigger?

Additional thought - is there any evidence that the basilisk ate bigger mammals, eg students?

Answer

I've gotten a lot of flak in my comments of the How did the Basilisk survive for a thousand years? question, regarding the fact that the Basilisk is a snake. However I do maintain that it is a snake as this quote from Chamber of Secrets indicates:

Of the many fearsome beasts and monsters that roam our land, there is none more curious or more deadly than the Basilisk, known also as the King of Serpents. This snake, which may reach gigantic size...

As far as snakes go, this article shows that snakes "can lower their metabolic rates by up to 70 percent, allowing them to survive prolonged periods without food". This is supported by the books in that the Basilisk does survive for a long period of time with seemingly only the food from stray animals in the castle.

The question of how it got so big is also answered in the same article:

Despite the lack of food, the snakes continued to grow in length. [...] this suggests that there must be a strong selective advantage to growing longer'

Snakes in "real life" even without food will continue to pour energy into growing longer (read bigger). I feel like this directly relates to the Basilisk, since it is a real world explanation regarding how it could gain so much size without needing as much food. When you add in the fact that it is a mythological creature this characteristic could be magnified in significance.