It is estimated that 36,000 elephants are killed each year – roughly one every 15 minutes.

If the killing continues at this rate, campaigners say, there could be no elephants left in the wild in 15 years.

During his visit to Kenya last month US President Obama announced steps to tighten restrictions on the sale of ivory from elephants, but despite such efforts – and attempts to rein in poachers – elephants continue to be killed for their valuable tusks.

Often when adults are killed the young, who have not yet grown tusks, are left behind.

On World Elephant Day, the BBC has been to visit the David Sheldrick Wildlife Trust’s elephant orphanage in Nairobi.