The lion which was legally shot dead by a hunter on December 30 was pictured with the teeth emerging from the back to its head. Biologists said they had never seen anything quite like it before. One theory suggests the teeth could be the remnants of a conjoined twin which died in the womb.

Another explanation is a so-called ‘teratoma’ tumor. This type of abnormality, whose Greek name translates to ‘monster tumor’, can grow teeth and hair. In humans, it can even grow fingers and toes. The Idaho Department of Fish and Game said the lion was hunted after it attacked a dog in Idaho and that a set of whiskers was also found springing from its head.