http://www.bbc.co.uk/nature/19909635
Bottlenose dolphins using sponges to protect their noses while foraging is a technique that the animals discovered in the 19th century, a study has found.
Scientists analysed data on the dolphins of Shark Bay, Australia, to model the appearance and transmission of the skill over generations.
The study found that "sponging" could have begun with a single "innovation event" between 120 and 180 years ago.
It suggested that mothers passed on the skill by teaching their offspring.
The analysis is published in the journal Animal Behaviour, and used previous field studies to investigate how sponging was established and maintained.