This clip from the BBC shows a Sandtiger Shark being given an ultrasound.
Sandtiger Shark caught off southern NSW
Photographer: Ian Merrington © Ian Merrington @ DPI Fisheries
Despite its 'overly dramatic presentation' the clip does present some interesting information about the unusual early life of the species. Yes, developing pups do eat their siblings before birth. Only one young survives in each uterus. It's known as intrauterine cannibalisation.