1. Has it been tested and observed numerous times by more than

one group of scientists?

Yes, it has.

Explanation:

Replicability of an experiment holds great importance in the scientific world. Different groups of scientists ought to be able to replicate a certain experiment to achieve the same results/conclusions as the first team of scientists did. This is essential to prove that the findings are credible and did not just occur by chance, which is the case here too.

i think it is true in my reasonment ..

as the gila monster consumes the eggs or young of the desert cottontail and gambel's quail, thus its main food supply is only accessible for a restricted time duration every year. however, for this, the gila monsters exhibit three adaptations, which elevate their survival rate in the desert condition.  

first, is that they possess huge bodies, and can consume greater concentrations of food during a small period. secondly, they require to feed infrequently as they can accumulate fat in their tails. ultimately, their rate of metabolism is very low, so that they can burn their reservoirs of fat gradually.