Antarctic Fish Have Ice In Their Veins

Scientists have revealed that some fish that thrive in the freezing cold waters of the Antarctic actually have ice in their veins. A protein in their system called notothenioids not only keep the fish from freezing to death, but also keeps ice crystals in their veins.

Although the ice crystals would melt at temperatures just slightly above freezing, the fish seldom if ever encounter water of such temperature, making the phenomenon virtually permanent. The study had been documented by the Proceedings of the National Academy of Sciences.

It appears that the same proteins that prevent their blood from freezing also bind to the ice crystals which prevents them from getting smaller. The study concluded that it is unclear as to whether evolution played a role in the ability for the fish to survive with the ice crystals in their system or if the formations lead to their eventual demise.

It’s definitely an interesting evolutionary tale: The very adaptation that allows these fish to survive in freezing water must have required other adaptations to keep from killing them.