Zookeepers at the Chester Zoo in Cheshire, England experienced a rare feat when about 200 Montserrat tarantulas successfully hatched, making the zoo the first in the world to accomplish the process in captivity, officials said.

Native to the Caribbean island of Montserrat, not much is known about the tarantula. This makes breeding of the species essential in understand more about the species. Gerardo Garcia, curator of lower vertebrates at Chester Zoo, said in a statement: “Breeding these tarantulas is a huge achievement for the team as very little is known about them. It’s taken a lot of patience and care to reach this point.”

After observing them in the wild, a keeper from the Chester Zoo brought a dozen of the spiders to the zoo in 2013. Over three years, they were studied to devise behavioral indications. Finally, a female Montserrat tarantula has given birth to almost 200 baby spiders.

The journey, however, has been challenging.

There is a difference between the lifespan of the female spiders and the males. While the male spiders can live for 2.5 years at the most, the females, with a longer lifespan, take much more time to mature. The other big problem was common for many invertebrates. According to Garcia, there was a threat that the female Montserrat tarantulas could prey on the male instead of viewing them as partners.

The next challenge was the disappearance of the three female tarantulas after they were finally impregnated.

“They literally dig a burrow in the ground, and they’re gone,” Garcia told BBC. “They don’t feed, they don’t show up, we don’t know what’s going on. You just have to leave it for several months and see what happens.”

Finally, a number of small spider babies started to appear from under the earth.

“We’re keeping them in small, individual pots,” Garcia said. “A member of staff is feeding them one-by-one with small flies, at the beginning. Then we’ll go for bigger prey like crickets.”

Over time, the “spiderlings” are expected to become a part of the system they were born out of as there remain no males in the existing adults.