By comparing P. furiosus with a related species of archaea, Pyrococcus abyssi, scientists have tried to determine the correlation between certain amino acids and affinity for certain pressures in different species. P. furiosus is not barophilic, while P. abyssi is, meaning that it functions optimally at very high pressures. Using two hyperthermophilic species of archaea lessens the possibility of deviations having to do with temperature of the environment, essentially reducing the variables in the experimental design