But what about creatures that are blind?

If you haven’t already, meet the eastern or common mole, Scalopus aquaticus. In addition to being cute in a kind of creepy way, these mammals are blind and have teeny ears. But they are remarkably good at finding their prey.

Ken Catania, a neurobiologist at Vanderbilt who studies animal sensory systems (he’s one of the researchers responsible for the sensitive alligator study we covered in Science in Action) decided to investigate the mole’s sense of smell.

He didn’t think the moles smelled in stereo—in fact, just the opposite. “I came at this as a skeptic. I thought the moles’ nostrils were too close together to effectively detect odor gradients.” But he’s a scientist—he needed evidence to support his assumption.

To test the theory of stereo smell, he created a radial arena with food wells spaced around the 180-degree circle with the entrance for the mole located at the center. He then ran a number of trials with pieces of earthworm placed randomly in different food wells.

When the mole first entered the arena, it moved its nose back and forth as it sniffed. Then, it seemed to zero in on the food source, moving in a direct path. This was pretty remarkable, and made Catania reconsider the idea of stereo sniffing.

“It was amazing. They found the food in less than five seconds and went directly to the right food well almost every time,” Catania said. “They have a hyper-sensitive sense of smell.”

Catania then blocked one of the moles’ nostrils with a small plastic tube. When their left nostrils were blocked, the moles’ paths consistently veered off to the right, and when their right nostrils were blocked, they consistently veered to the left. They still found the food but it took them significantly longer to do so.

Voilà! Stereo-smelling! (A video of the trials demonstrates this very clearly.)

Catania proved himself wrong and published his findings this week in Nature Communications.

What about the rest of us mammals? Do we smell in stereo?

“The fact that moles use stereo odor cues to locate food suggests other mammals that rely heavily on their sense of smell, like dogs and pigs might also have this ability,” Catania says. But as for humans, he remains skeptical. I guess stereo- vision and hearing is enough…

Image: Ken Catania

These animals are subject to terrific stresses underground: darkness, scarcity of food, immense numbers of pathogens and low oxygen levels. So they have evolved a range of mechanisms to cope with these difficulties.

One of these mechanisms is resistance to cancer. That’s right: blind mole rats and their subterranean cousins, naked mole rats, are the only mammals known never to develop cancer.

Three years ago, a team of researchers published a study of how naked mole rats avoid the disease. In these animals, cancerous cells get claustrophobic and stop multiplying. The research found that a specific gene—p16—makes the cancerous cells in naked mole rats hypersensitive to overcrowding, and stops them from proliferating when too many crowd together.

Scientists figured it would be the same in blind mole rats. Nope!

A paper published this week in the Proceedings of the National Academy of Sciences finds that precancerous cells in blind mole rats commit suicide!

The researchers isolated cells from the animals, grew them on a culture plate, and forced them to proliferate in numbers beyond what occurs in the animal. After dividing approximately 15-20 times, all of the cells died rapidly. The researchers determined that the rapid death occurred because the cells recognized their pre-cancerous state and began secreting a suicidal protein, called interferon beta. The protein kills both abnormal cells and their neighbors, resulting in a “clean sweep.”

“Not only were the cancerous cells killed off, but so were the adjacent cells, which may also be prone to tumorous behavior,” says co-author Andrei Seluanov of the University of Rochester.

Lead author Vera Gorbunova, also of the University of Rochester, believes the anti-cancer mechanism evolved as an adaptation to subterranean life. “Blind mole rats spend their lives in underground burrows protected from predators. Living in this environment, they could perhaps afford to evolve a long lifespan, which includes developing efficient anti-cancer defenses.

“While people don’t use the same cancer-killing mechanism as blind mole rats, we may be able to combat some cancers and prolong life if we could stimulate the same clean sweep reaction in cancerous human cells,” says Gorbunova.

Image: University of Rochester