Kristin O’Brien is a biologist at University of Alaska Fairbanks, who studies an unusual family of fishes called icefishes.
They’re found only in the Southern Ocean surrounding Antarctica. They are unique because they are the only vertebrates in the world that lack the oxygen-binding protein hemoglobin, which is the protein that transports oxygen throughout the body and gives blood its red color.
In other words, the blood of an icefish isn’t red. Instead, its blood runs a cloudy white. “I think these animals are among the most fascinating creatures on Earth,” Dr. O’Brien said.
Antarctic icefishes – which are within the Channichthyidae family – are an example of the wondrous possibilities that can arise during evolution in a cold environment. Icefishes are aptly named for their translucent bodies and blood. They’re the only vertebrates on the planet that don’t have red blood. Instead, white blood circulates through their blood vessels.