![]() |
Credit: Wikimedia Commons / Marrabbio2 |
Icefish are the only vertebrates that lack red blood cells and hemoglobin as adults. In vertebrates, these are essential for binding oxygen and then transporting oxygen throughout the body. But rather than this being a “simple adaptation,” the icefish of the Channichthyidae family appear to have several major anatomical and chemical alterations compared to other similar fish (even other Antarctic species within the same order, from the Nototheniidae family). The icefish has extremely large gills for its body size, no scales (which may help it to absorb oxygen from the surrounding water), a flexible (and less dense) bony skeleton. It also has a heart four times the size of similar fish, larger blood vessels than other similar-sized fish, has accumulated a lipid layer in its bloodstream that makes it more buoyant, and makes more antifreeze-like proteins than other cold-water fish. Oxygen exists solely in physical solution in icefish blood, which has an oxygen-carrying capacity of less than 10% compared with that of their relatives with hemoglobin.To read the entire article, click on "Clear as Blood: How Did Antarctic Icefish Survive Their 'Evolution'?"
Looking for a comment area?
You can start your own conversation by using the buttons below!