Genetics in action

Through an analysis of 135 years’ worth of photographs, a research team at the University of Cambridge has found evidence that all species of rhinoceros : white, black, Indian, Javan and Sumatran have seen their horn lengths decrease "significantly" over time.

The reason for this is because trophy hunters and poachers have concentrated on individuals with the largest horns. The survivors will likely be genetically programmed to produce shorter horns and thus average horn size has reduced over time.

The skull in the photograph is from a long dead Sumatran rhinoceros Dicerorhinus sumatrensis. Today there are probably less than 100 individuals of this species left alive.

What a pig's dinner we are making of our wonderful world!