The princes made royal internet history as they appeared for a live question and answer session today.
Hong Kong is acting as the gateway for illegal ivory entering China - where the item is high in demand.
Prince Charles and Prince William joined launched a campaign to save endangered species like rhinos, tigers and elephants from poachers.
The public have been given another window into the upbringing of Prince George with a new official family photograph showing the eight-month-old royal with the Duke and Duchess of Cambridge and their pet dog Lupo.
The young family are seen posing out of a window at their home in London's Kensington Palace in the first official photo of Prince George since his christening last October.
The young prince is seen wearing a jumper with his name emblazoned across it and gazing at the family's black cocker spaniel, while his parents fix their eyes on the camera.
The Maori King has pulled out of a meeting with the Duke and Duchess of Cambridge during their New Zealand tour.
His officials suggested the engagement was not long enough to do justice to the status of the royal visitors.
"They were offered a 90-minute slot, that was longer than pretty much any other engagement that they have, and King Tuheitia's people decided that wasn't long enough and on that basis they rejected him attending," New Zealand Prime Minister John Key said in statement.
The Cambridges were due to meet King Tuheitia, a former truck driver who ascended to the throne in 2006, on the country's North Island at Turangawaewae, his official residence and reception building.
The Maori King's office issued a statement which reportedly quoted a senior official who said the monarch was "not some carnival act to be rolled out at the beck and call of anyone, and nor should we be prepared to compromise our tikanga to fit into a pre-determined schedule".
Prince William wants all ivory in the Royal Collection at Buckingham Palace to be destroyed, according to a leading primatologist.
Leading primatologist Jane Goodall told the Independent on Sunday that the Duke of Cambridge had told her he would "like to see all the ivory owned by Buckingham Palace destroyed".
Prince Charles has reportedly also asked for all ivory items at his Clarence House and Highgrove homes to be removed during the last few years.
Charles and William called on the world to turn its back on illegally traded animal parts like ivory and rhino horn in a video appeal earlier this month.
Illegal trade in animal parts such as rhino horn, tiger parts and elephant tusks is worth more than an estimated £11.5 billion each year.
Princes William and Harry have left the flood-hit village of Datchet in Berkshire after a day moving sandbags in a "private" mission to help residents.
Princes William and Harry formed a human chain to unload sandbags from an Army vehicle as they joined colleagues from the armed forces in helping to defend Datchet from the floods.
The private visit was unannounced but once news of their work spread, they were followed by journalists and cameramen.
Asked by ITV News whether he was enjoying helping, Prince Harry replied: "Not really with you guys around".
William and Harry's visit to flood-hit Datchet has "gone down very well", according to the village's parish clerk.
"They were very involved and wanting to know what was going on," parish clerk Graham Leaver said.
"They have been in Datchet and the area and I think it's gone down very well. That is my assessment.
"They were very natural. To be honest, they could have walked in among people here and nobody would have recognised them looking at the way they were dressed.
"They came into our parish office and it took most of us a few minutes to realise they were there. They were particularly interested in talking to the troops."
Princes William and Harry have now left the flood-hit village of Datchet after spending the morning helping to defend the town from the floods.
The royals, dressed in waterproofs and wellington boots, moved sandbags from an Army vehicle onto the back of a train wagon where they were then delivered to homeowners who have struggled to defend their properties.
Asked by ITV News whether he was enjoying helping in flood-hit Datchet, Prince Harry replied: "Not really with you guys around".
The royals were spotted on their "private" mission to help residents by journalists this morning and they have since been followed by reporters and photographers as they continue their visit.
Earlier, Prince William suggested that reporters should "come and help instead of throwing cameras around" after he was pictured loading sandbags in the flood.
Prince William has suggested that reporters gathered in flood-hit Datchet should "come and help instead of throwing cameras around."
The Duke of Cambridge was speaking to ITV News reporter Rupert Evelyn shortly after being pictured alongside his brother Harry helping to move sandbags in the Berkshire village.