Mei Lun and Mei Huan, the first surviving pair of giant panda twins ever born in the U.S., are officially on their way to Chengdu, China, for a new home at the Chengdu Research Base of Giant Panda Breeding. The 3-year-old giant pandas left Atlanta in the early-morning hours of November 3, 2016.

The twins, who are the fourth and fifth Atlanta-born pandas to travel to China, are accompanied by two Zoo Atlanta staff and a considerable amount of panda-particular luggage, including around 375 pounds of bamboo, 8 gallons of water, and 25 pounds of favorite treats, including sugarcane, bananas and giant panda biscuits.

Photos | Panda twins' sweet send-off from Zoo Atlanta

“This is a milestone to be celebrated. While the Zoo Atlanta family and their many fans will miss seeing Mei Lun and Mei Huan in Atlanta, we’re very proud to see two more Atlanta-born giant pandas go to join such an important program,” said Raymond B. King, President and CEO. “It’s a tribute to the success of the Zoo Atlanta giant panda program and to the commitment of our international partners who are helping us save this species.”

Mei Lun and Mei Huan will join one of Zoo Atlanta’s longest and most successful conservation collaborations. Zoo Atlanta has contributed more than $10 million in sustained support for conservation of the species, and eight of the Chinese nature reserves inhabited by wild giant pandas are supported by Zoo Atlanta. The International Union for the Conservation of Nature (IUCN) upgraded the giant panda’s status from “endangered” to “vulnerable” in September 2016, but the species remains heavily reliant on conservation programs. Fewer than 1,900 giant pandas are estimated to remain the wild in China’s Sichuan, Shaanxi and Gansu provinces, where they face continuing threats from habitat fragmentation and habitat loss as a result of deforestation and other human activities. More than 1,200 of China’s remaining wild giant pandas live inside nature reserves like those supported by the Zoo.

Fans from around the world tuned in for Mei Lun’s and Mei Huan’s final days on the Zoo’s PandaCam, and many traveled to join the pair at Zoo Atlanta on October 30, when the twins enjoyed special travel-themed enrichment surprises, including a giant passport, globes and a “China or Bust” banner celebrating the duo’s milestone transition to a future at the Chengdu Research Base, where their parents, Lun Lun and Yang Yang, were born, and where their older brothers and sister, Mei Lan, Xi Lan and Po, now reside.

Giant pandas are a solitary species and are weaned from their mothers by the time they are around 18 months old. Mei Lun and Mei Huan have been living apart from their mother since February 2015 and at 3 years old, are ready for this next step in terms of both their age and behavior.

Lun Lun’s and Yang Yang’s youngest offspring, a new set of female twins born September 3, 2013, will follow in their older siblings’ footsteps as they begin to achieve many important milestones of their own. The 2-month-old twins, who can currently be seen on PandaCam hosted by Animal Planet L!VE at zooatlanta.org/pandacam, are expected to make their debut in December 2016 or January 2017. Like Mei Lun and Mei Huan before them, the twins will be named in accordance with the Chinese 100 Day tradition on their 100th day on December 12, 2016.

Stay tuned to Zoo Atlanta Facebook, Twitter and Instagram for social media updates on Mei Lun’s and Mei Huan’s travels, and visit zooatlanta.org for blog posts on the giant pandas. Visit the cubs’ father, Yang Yang, at the Arthur M. Blank Family Foundation Giant Panda Conservation Center.