Animal campaigners are really upset after a type of dolphin which has enchanted people in China for generations was declared extinct.
The Yangtze River dolphin was worshipped in ancient times because some people thought it was a goddess.
But it's feared that there aren't any more of the dolphins left - and that's being blamed on humans.
Campaigners say pollution, too much fishing and not enough protection for the dolphin has led to this situation.
It's thought to be the first time that a creature like this has been declared extinct for 50 years.
The dolphin - or baiji as it is sometimes known - was last spotted five years ago.
Last year, experts failed to find any trace of the dolphins in a special six-week search.
The creature will now be listed as critically endangered and possibly extinct.
"Even if there are a few left, we can't find them and we can't do anything to stop their extinction," said search team member Dr Sam Turvey of the Zoological Society of London.
He described the news as shocking and tragic.
Animal campaigners are now hoping that what has happened to this dolphin will encourage people across the world to do more to protect endangered creatures and stop them dying out.