"Even though our work is attempting to make the seemingly impossible possible – i.e., to ensure the survival of animals that would otherwise probably disappear from our planet – it must remain an exception and not become the rule. Despite all the buzz around what we are doing in the lab, this can at best make a small contribution to saving these rhinos from extinction. The protection and conservation of the animals’ few remaining habitats is at least equally important,” said Dr. Vera Zywitza, a stem cell scientist from Max Delbrück Center.

Photo: YouTube/National Geographic

Dr. Sebastian Diecke, head of the Pluripotent Stem Cells Platform at the Max Delbrück Center in Berlin, and Dr. Zywitza head the team that's endeavoring to revive the population of the critically endangered Sumatran rhinos.

Today, there are fewer than 80 Sumatran rhinos left in Indonesia’s Gunung
Leuser and Way Kambas National Parks on the island of Sumatra and in Kalimantan. In Malaysia, this ancient species and the only rhino species with hair has already gone extinct after the death of the country's last male and female Sumatran -- Kertam and Iman -- in 2019.

Photo: YouTube/National Geographic

With the demise of Kertam, Malaysia's hope to save their Sumatran rhinos was shattered. “I remember so well when Tam was captured and the high hopes everyone had that he could be the founding member of a successful captive breeding program in Sabah and join the then-international efforts involving the US and Indonesia,” said Susie Ellis, executive director of the International Rhino Foundation, in a statement. “Sadly, those hopes were repeatedly dashed over the next decade by a series of incidents, some sociopolitical, some biological, and some simply bad luck.”

Malaysia tried to hold on to what remained of its hope through Iman, but she too suffered from reproductive pathologies and passed away that same year.

Photo: YouTube/National Geographic

And yet, Dr. Zywitza and Dr. Diecke refused to accept this tragic fate of the Sumatran rhinos. Through sophisticated technologies acquired from the BioRescue research project that's dedicated to saving the even more critically endangered northern white rhinos – of which there are only two females left -- the team had been able to preserve Kertam's and Iman's skin cells and turn them into induced pluripotent stem (iPS) cells.

From these iPS, Dr. Silke Frahm-Barske, who is also a scientist in Diecke’s research team, grew brain organoids or mini-brains. “To the best of our knowledge, mini-brains like these have only been obtained from mouse, human, and non-human primates so far. So we were very pleased to see that the stem cells we generated from the Sumatran rhino formed organoids quite similar to those of humans,” explained Frahm-Barske.

Photo: YouTube/National Geographic

Their next goal is the production of sperm cells from Kertam's skin cells, which is more complex because they have to cultivate primordial germ cells from the iPS cells. But they are very hopeful, and when they succeed, egg cells from Iman and other deceased female rhinos will be produced. Then, fertilization will be done in a petri dish, and then they'll be developed into baby rhinos through surrogate rhino mothers.

It's pure hard work, but with the initial success of their painstaking effort, the team is fulfilling what Malaysia had hoped for. To build a new future for the Sumatran rhinos through Kertam.

https://www.youtube.com/watch?v=FcJrQ9pUq5k