Screw-shaped bird sperm swim faster — but it comes at a cost
IMAGE: The helical sperm of the bluethroat (Luscinia svecica). view more Credit: Hanna Støstad The research was part of the thesis of PhD student Hanna Nyborg Støstad, investigating the peculiar spiral shape of songbird sperm. Støstad compared sperm cells of 36 bird species, from house sparrows to tree swallows, and found that species whose sperm had…