Tooth in poo suggests ancient shark ate its young

Scientists have discovered a baby tooth in the fossilised faeces of a prehistoric shark, and concluded that the animals ate their own young.

This rare evidence of "filial cannibalism" was only revealed because the shark's corkscrew-shaped rectum produced dung in a distinctive spiral.

One such dropping, collected in Canada, holds a tiny tooth of the same species.

These Orthacanthus sharks lived in coastal swamps and may have resorted to cannibalism as they expanded inland.

Swampy sharks

The macabre sample was gathered by University of Bristol masters student Aodhan Ó Gogáin, now studying for a PhD at Trinity College Dublin, as part of a wider investigation into prehistoric fish on the coast of New Brunswick.

Like much of North America and Europe, this land used to sit near the equator and was thick with tropical jungles.-read more