EUGENE, Ore., Sept. 23 (UPI) -- Fish species that make their home in the frigid waters of Antarctica have developed special antifreeze proteins that keep their blood from icing over. But evolution is a strange game in which seemingly every adaptive trait comes with a trade-off, and for the fish of Antarctica that trade-off is quite the paradox.
For the benefit of avoiding frozen blood, Antarctic notothenioid fish species must tolerate ice in their veins. That's right, the same antifreeze proteins that latch onto ice crystals and prevent them from growing also inhibit them from melting.