Scientists bred a frog that only lived for 3 days. It was an extraordinary achievement.

Once a species is extinct, it's gone forever, right? A group of Australian scientists would beg to differ.

There are thousands of endangered or vulnerable species in the world right now.

These include animals like the black rhino, the hawksbill turtle, the pangolin, and the Sumatran elephant.

A black rhino lopes through the Masai Mara Game Reserve in Kenya. There are only a few black rhinos left in the world. Photo by Dan Kitwood/Getty Images.

Right now, these species have very little chance of living past the next 50 years. But one little frog could change all that.

In the 1970s, Australian scientists discovered a new breed of frog with some interesting behaviors.

The Guardian reports that the Gastric Brooding Frog was unlike any frog scientists had seen before.

As its name suggests, it swallowed its fertilized eggs and newly hatched tadpoles whole. Then the frog's stomach, which functioned like a uterus, would incubate the frogs until they were fully formed.

Scientists had never seen a species behave like the Gastric Brooding Frog, which made it an immediate topic of fascination. Image via University of New South Wales.

And how did the female frog get her frog children back into the world once they were fully formed, you ask? She projectile-vomited them, of course.

These scientists thought the Gastric Brooding Frog could lead to some huge discoveries.

The functions of this frog's extra-special stomach had the potential to help us discover new procedures that could be used in human medicine (think better treatments for stomach ulcers, new antibiotics or even improved fertility treatments).

But then, just as quickly as they popped up, the Gastric Brooding Frogs disappeared in the early 1980s. The same excited scientists determined that the skin-based chytrid fungus wiped them all out. The frogs were extinct.

Here's the cool part, though: 30 years later, those scientists are back on the Gastric Brooding Frog's case once again.

"This is definitely the most extraordinary frog that ever lived anywhere in the world," scientist Michael Archer said when asked about this particular breed of frog for an episode of the "Catastrophic Science" video series.

That's why Archer, a scientist at the University of New South Wales, chose the Gastric Brooding Frog for his next big project, titled "The Lazarus Project."

Archer wants to bring the extinct Gastric Brooding Frog back to life, a process he's calling de-extinction.

Archer hopes that with the help of a group of internationally renowned scientists, he can bring an extinct frog back from the dead. Image via University of New South Wales.

Where do you start when bringing back an extinct frog?

It's just as tough as it sounds.

First, the scientists had to locate a freezer full of dead (but preserved) Gastric Brooding Frogs. From there, the project looks a lot like an "Orphan Black"-style cloning mission.

At a basic level, the scientists take one cell from a frozen Gastric Brooding Frog and put that cell in the DNA-less egg of another, more common Australian frog. That egg will develop into a tadpole eventually — but it should develop into a Gastric Brooding Frog, rather than a common frog.

Remember when scientists cloned Dolly the sheep? This project builds on that research, but scientists are hoping for even better results. Image via University of New South Wales.

The project has been successful so far, but there are still many obstacles.

According to the scientists on the research team, they're well on their way when it comes to creating the second coming of the Gastric Brooding Frog. They've seen embryos divide, which is an incredibly good sign.

But those embryos have only lived for three days so far, so there's still a lot of work to be done.

This little extinct frog could teach us how to (literally) bring species back from the dead. Image via University of New South Wales.

The ramifications of this project for other near-extinct species (and for humans) are huge, though.

"There is increasing interest in the fact that many animals are becoming extinct all over the world," Archer says in the "Catastrophic Science" video. "We're losing biodiversity. We need to find some animal that can be demonstrated to be brought back from the dead."

For more information about de-extinction, check out this University of New South Wales "Catastrophic Science" video, republished on The Guardian.