SPATA, Greece (AP) — The world’s most endangered tigers have started a family in Greece, offering hope for a predator rapidly vanishing from the wild.

Three 2-month-old Sumatran tiger cubs received identification microchips and their first vaccinations Tuesday at a zoo near Athens, as part of a global effort to build a backup population.

The Sumatran tiger, classified as critically endangered, is found only on the Indonesian island of Sumatra, which is slightly larger than Sweden.