How to sharks make new sharks? There are a variety of different modes, from laying egg cases to giving birth to live, swimming mini-sharks. We can use medical techniques to learn more about reproduction. This is an ultrasound from a pregnant shark, showing embryonic sharks inside the uterus. Start of video shows an embryo from above, with eyes, gills and spine visible. Second part of video show an embryo from below, showing mouth, making pumping motions to “breathe”. Vertical side of image is 25 cm (10 inches).