Mimicking nature's processes has been a field of many scientists' interests. Though some of them have managed to create things like artificial rain, science hasn't really come close to challenging nature. But don't you relax nature, we're coming for you. And we've upped our game. We've developed artificial animals now. Sounds amazing, right? That's right, folks! Bioengineers at Harvard's Wyss institute, led by Kevin Kit Parker, have created a small light controlled stingray using a metallic skeleton and that moves with the help of actual rat heart muscles. What's more, its body is 3D-printed. Okay, not completely an animal. Part-animal, part-machine. Even cooler, they've created a cyborg. The muscles of the 'device' are stuffed with rat-DNA to make it light-sensitive. The “artificial animal,” and “bio-inspired swimming robot”, as the creators call it, uses a simple and elegant motion to move forward and make a turn. It's essentially one big fin, which moves in controlled waves. The team also managed to manoeuvre this stingray through an obstacle course. Okay, all this biology stuff is cool. But is it of any use? Apart from giving a vague sense of achievement (and probably a few scientific awards, and millions of dollars in cash too) to people who created it, what good does an artificial stingray do? Good question. The team behind this considers this a training exercise on the way to create an artificial human heart. Speaking to the National Public Radio, Parker says that although the heart and a stingray fin are very different, they both need to overcome problems related to pushing fluids. The way a human heart propels blood out is similar to the way a ray propels itself through water. Artificial hearts nowadays are usually made as versions of mechanical pumps. A heart made from living cells would behave much more like a natural heart, and would be able to grow and change over time, Parker says. "The heart's built the way it is for a reason," he says. "And we're trying to replicate as much of that function as we possibly can."