Scientists have found signs of four Javan rhinos born in recent weeks in Indonesia, a surprising baby boom for a species that may be reduced to fewer than 60 individuals worldwide…

Signs of the rhino calves were discovered in Indonesia's Ujung Kulon National Park by a team of biologists who were checking on the rhinos after the recent earthquake on the island of Java. These are the first known births for the Javan rhinos in three years.

"Javan rhinos are probably the rarest large mammal species in the world," said Arman Malolongan, a director at Indonesia's Ministry of Forestry. "To discover that this population is breeding, and even slowly growing, gives us hope for the species' future."

Javan rhinos are the rarest of the world's five rhino species. It is estimated that between 28 and 56 Javan rhinos live in Ujung Kulon.

The team found the first sign of a calf a few weeks ago, with the discovery of a small footprint (about 16-17 cm) along with a larger footprint belonging to the mother. One day after this first discovery, another set of mother and calf footprints of slightly different size was found in a different area. Both signs were estimated to be three days old or less. On the same day, a second team came face-to-face with a mother and female calf. And the following day, the team found a fourth small footprint in a different location.

Because of the distance between the four areas where the discoveries were made and the differences in the size of the footprints, the team concluded they are evidence of four different calves.

Javan rhinos are vegetarians that live deep inside the rainforest and it's very unusual to catch a glimpse of them.