Blood color seems to have several biological consequences in addition to the social consequences of the caste system. Troll tears are apparently the same color as their blood, though more diluted in color. Trolls lower on the hemospectrum are more likely to have psychic powers, but are more psychically susceptible as a result. On the other hand, trolls higher on the hemospectrum seem to be more physically strong. Another obvious aspect is the different anatomy of land- and sea-dwelling trolls. The latter sport fin-like protrusions and organs that allow them to live underwater.