Seven per cent of pet dogs – largely small, “toy” breeds – have doubled-up tooth, harking back to sharks’ mouths. The situation, often known as persistent deciduous tooth, happens when the canine’s child tooth stay mounted within the jaw, near the grownup tooth, as a substitute of falling out, creating rows of tooth just like these seen in sharks.
To examine these “shark teeth”, Corrin Wallis at Waltham Petcare Science Institute in Leicestershire, UK, and her colleagues examined the information of two.8 million purebred dogs in…