Cavefish live in underground caverns, where the water is unaffected for long periods of time. Studies have shown that standing water pools can have significantly less dissolved oxygen than surface water.
Boggs said that while they are mobile all the time and have limited access to nutrition, they do not have enough food. It’s a paradox. They are wasting all their energy. Where does this energy come from?
Cavefish have higher hemoglobin levels than surface fish, according to blood samples. Researchers at UC assumed that cavefish would have a higher hematocrit, a clinical measurement of the relative contribution to red blood cells in whole body blood.
Researchers expect to find red blood cells in cavefish that are larger than previously thought.
Gross said that they were nearly identical. We couldn’t figure out why.
UC biologists compared red blood cells from both fish and found that the ones of cavefish were significantly larger. Gross compared them with softballs to the baseballs made by surface fish.
Gross stated that this alone is what explains the different hematocrits. We don’t know much about the evolution of cell size, so this finding could be a key to understanding how animals develop increased hemoglobin levels.
Gross suggested that cavefish might be able to forage longer in low-oxygen environments due to their higher hemoglobin levels. Cavefish have to work harder to find the limited food they can find in caves.