– Those magnificent gray giants that symbolize the wonders of the wild may be big, but they are very vulnerable these days.

That’s the message behind World Elephant Day on Tuesday, an effort involving the 96 Elephants campaign and more than 100 zoos across North America to highlight the plight of African elephants.

Conservationists worry that relentless poaching of the animals, slaughtering them for their ivory tusks, could drive the species to extinction within a decade.

“We will be raising awareness of both captive and conservation issues that surround elephants,” said Gina Kinzley, senior elephant manager at Oakland Zoo, which is participating in Tuesday’s event. (The Minnesota Zoo in Apple Valley does not have elephants.)

The numbers tell the story. In 1979, there were an estimated 1.3 million African elephants; by 1989 numbers fell dramatically, to 600,000. That’s when an international ban temporarily slowed poaching, but numbers are still falling, Kinzley said. In 2012, an estimated 35,000 elephants were killed for their tusks, which equates to about 96 per day — or one every 15 minutes.

Conservationists now estimate there are 400,000 left, said Kinzley, and without action, those numbers could dwindle further.

Earlier this year, the Obama administration enacted regulations on importing ivory, with the U.S. Fish and Wildlife Service taking steps toward a near-total ban on commercial elephant ivory trade.

“Today, because of the actions of poachers, species like elephants and rhinoceroses face the risk of significant decline or even extinction,” President Obama said in announcing the National Strategy for Combating Wildlife Trafficking in February.

Tuesday’s event is part of the 96 Elephants campaign, to send 96,000 messages to U.S. public officials to support a ban on the sale of ivory. The campaign was named for the estimated 96 elephants slain each day for their ivory.

Supporters at the Oakland Zoo are being asked to don a gray ribbon, available at the zoo, or simply wear gray. Participants can then take “elphies” at the elephant exhibit, or hold signs of support and post images on social media using the hashtag GoGrey.