Elephants are equipped to survive every challenge except us.

But because we slaughter close to a hundred elephants every day to sell their tusks for the ivory, it’s possible the elephant might not survive at all.

Every part of the message isn’t that bleak in Nat Geo’s Destination Wild “Mind of a Giant,” an intriguingly scientific elephant documentary that airs Sunday at 9 p.m. ET. But Caitlin O’Connell, one of the experts interviewed on the show, warns that the bottom line is it could be.

“The ivory trade is in no way sustainable,” says O’Connell, a consulting faculty member at Stanford who has studied elephants in the wild for 25 years. “If we’re serious about protecting elephants, I believe ivory should not be sold at all.”

O’Connell notes that as long ago as 1989, Kenya staged a public ivory burn (right), torching 12 million tons of illegally harvested tusks and rhinoceros horns.

The Kenyan government hoped to show it was serious about stopping poachers and protecting its elephant population, which had become a major tourist attraction.

“I was hopeful after that burn,” says O’Connell. “But you look around today and we’re back at the [poaching] levels of 25 years ago.

“There are more awareness programs now to educate people on how special and intelligent these animals are. But they’re still being killed.”

“Mind of a Giant” shows footage of Satao (top), an elephant that, for years, was said to be the largest in Africa. The producers note that his tusks, because of their size, could bring up to $250,000 in the illegal ivory market.

In 2014, Satao was killed by poachers.

“Mind of a Giant,” while it addresses the poaching issue, primarily focuses on elephants themselves, concluding that by any measure, elephants are remarkably intelligent.

Herds of elephants have figured out where they are protected, and where they are threatened by poachers. These herds will queue up in the protected zone at twilight and when it gets dark, hurry across the unprotected area to reach another safe zone.

Elephants recognize their image in mirrors. Elephants can figure out how to retrieve food from a setup that requires two elephants to pull on separate ropes simultaneously. In one study, one elephant figures out that she doesn’t have to pull at all, simply stand on the rope while the other elephant does the pulling.

“Elephants can assimilate and assess data,” O’Connell notes, enabling them to solve problems in ways we might assume are unique to humans.

On an equally interesting plane, the elephants in “Mind of a Giant” gather around and mourn fallen family members. On a lighter note, O’Connell says they have a sense of humor.

“I’ve worked with an elephant at the Oakland Zoo,” she says, “who would straighten his trunk and jab it into you, like a playful punch to the shoulder. It startled me the first time – and after he did it, he rocked back and forth from side to side, like he was enjoying that he’d ‘gotten’ me.”

Some of O’Connell’s longer-term studies have shown that elephants are highly sensitive to vibrations in the ground, which enables them to set up a relay system of warnings when there’s danger ahead.

“They have extremely well-developed auditory and olfactory senses,” she says. “We’ve found elephants can identify specific humans they know could harm them, by the color of their clothes or their smell.

“If you measured elephants against humans by the acuity of their senses, elephants would come out ahead. The only reason we think of ourselves as superior is that humans value vision so highly. In many of the other senses, we’d be far behind.”

An obvious question here, then, is that if elephants understand people are often a threat, why don’t elephants simply avoid us?

“Often in places where they can, they do,” O’Connell says. “They’ll wait until dark to travel in many populated areas. The problem is that humans are spreading out so much that there are fewer and fewer areas where it’s possible not to come in contact with us. So elephants, like other wildlife, have to adapt.”

The consequences of this interaction can get complicated.

“When I was working in Namibia,” she says, “the government instituted a ban on shooting elephants. But that created a problem for farmers. If you’re a poor farmer trying to grow corn in Namibia, you need some way to protect your crop from elephants or you will have nothing.”

Still, it’s the elephants that usually get the shorter end of the interaction stick.

When poachers kill the older elephants, which have the larger and more valuable tusks, it leaves a herd with a younger population. That creates the same kind of crisis that would arise with a human family consisting mostly of teenagers.

“Studies have shown that younger male elephants behave very differently when there aren’t bulls in the herd,” says O’Connell. “In some ways they don’t know how to behave. Since elephants live in family groups, that’s a big problem.”

Like “Mind of a Giant,” O’Connell says she’d like to be optimistic that people and elephants can eventually work it out.

She just hopes we recognize the value and importance of elephants – and other wild animals – before our greed and indifference kills them off.

“I was more optimistic a few years ago,” she admits. “Now it sometimes feels like we’ve fallen back into the dark ages.”