Singapore – In response to the extinction crisis facing pangolins, one of the world's most heavily trafficked mammals, scientists in Singapore have established a proactive conservation measure. Researchers at the Mandai Wildlife Group announced that they have created a biobank to collect and cryopreserve pangolin sperm, in preparation for potential artificial insemination programs in the future.
Currently, eight species of pangolins are known worldwide, and they face severe threats due to indiscriminate poaching. In particular, the Sunda pangolin is critically endangered, with its population having declined by more than 50% over the past 15 years. According to the International Union for Conservation of Nature (IUCN) Red List, all pangolin species are threatened with extinction, and scientists are striving to secure genetic material "before it's too late" to build a safety net for species conservation.
Researchers at the Mandai Wildlife Group have successfully extracted and stored sperm from 38 pangolins to date. However, collecting eggs from female pangolins has not yet been carried out because it is a much more invasive procedure compared to sperm collection in males.
Dr. Sonja Luz, CEO of Mandai Nature and Chief Conservation Officer of Mandai Wildlife Group, emphasized the importance of this biobank, saying, "We're really worried that we're going to have too many situations where we regret that we were too late."
With four species each in Asia and Africa, pangolin populations are declining globally due to habitat destruction and poaching. High demand for their scales, used in traditional Chinese medicine, has made pangolins the most trafficked mammals in the world. International trade in wild pangolins is prohibited under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), 1 and Singapore has also strengthened its Endangered Species (Import and Export) Act in 2022, imposing fines of up to S$100,000 (about US$74,000) and imprisonment of up to six years for poachers.
In urban environments like Singapore, the biggest threat to Sunda pangolins is vehicle traffic. However, as an international transportation hub, Singapore recognizes the serious impact of the illegal wildlife trade. In a six-day period in April 2019, Singaporean authorities confiscated approximately 26 tons of pangolin scales, estimated to be worth US$77 million, en route from Nigeria to Vietnam.
The Mandai Wildlife Group first started biobanking a decade ago when it began assisting with the conservation of the endangered giant panda. To support in vitro fertilization and endocrine research, they established a laboratory equipped with freezers and cryogenic storage facilities within the Wildlife Healthcare and Research Centre at the Mandai Wildlife Reserve.
Mandai currently houses six pangolins and receives more than 30 rescued wild pangolins each year for rehabilitation before they are released back into the forest. This environment provided an opportunity to aid the conservation of another endangered species, the pangolin, and staff began collecting pangolin samples in 2016.
When a pangolin arrives at the wildlife hospital, the medical team conducts a comprehensive health check under general anesthesia, including blood tests and ultrasound scans. In males, semen is collected, while eggs have not been collected from females to date. Dr. Luz explained, "Collecting semen under anesthesia is completely harmless to the animal. However, egg collection is a very invasive procedure and requires the use of an endoscope. We always prioritize the welfare of the animals in any action we take." Researchers have also attempted to collect eggs from deceased pangolins but have been unsuccessful and have confirmed that their current equipment cannot process and store eggs.
Semen collection is performed either manually or through electroejaculation. In the electroejaculation process, a small device is inserted into the pangolin's rectum and positioned near the prostate gland. Electrical pulses are then applied to stimulate the prostate and induce ejaculation. This method is commonly used in livestock and has also been utilized in sperm banks for men with spinal cord injuries or other health conditions.
Once semen is collected, researchers must complete the biobanking process within minutes due to the temperature-sensitive nature of the sperm. Fortunately, the wildlife hospital's laboratory and biobank are located within the same building, allowing for rapid processing. Veterinarian Charlene Yeong stated that each sample is analyzed for integrity and motility before being stored.
The research team has also developed a new technique for providing oxygen to anesthetized pangolins. Initially, oxygen was supplied using a cone-shaped mask placed over their unique pointed heads, but later, a tube system was developed to provide more precise control over gas flow, increasing efficiency. Dr. Luz noted, "Gas delivery via a mask is not easy to control, but intubation allows us to control the oxygen flow much better."
The researchers have also pioneered another world-first technique for pangolins. In addition to semen collection, they collect fibroblasts (tissue cells) that can be converted into stem cells and then reprogrammed to potentially recreate life. While eggs are still needed to create an embryo, research is underway to convert cells obtained from pangolins that died in traffic accidents into sperm cells.
Dr. Dan Challender, a pangolin researcher and conservationist based at the University of Oxford who has been involved in pangolin research and conservation for 15 years, said, "I think pangolin sperm biobanking has potential applications in the future for conserving this species. However, we hope that these technologies won't be needed because we've addressed the major threats to the species and secured healthy wild pangolin populations."
The Mandai Wildlife Reserve has successfully bred three baby pangolins naturally by housing breeding pairs together. While they have not yet used pangolin sperm for artificial insemination, they are storing it for research and potential future use in assisted reproductive technologies.
Dr. Luz stated that natural breeding is ideal but emphasized the importance of mastering artificial insemination techniques now, citing the case of the northern white rhino. Currently, only two females remain, making the species functionally extinct. Dr. Luz warned, "Once you get to a situation where you don't have enough individuals left to breed, it's too late."
The goal of the pangolin biobank is capacity building. They have secured samples from 38 pangolins to date, and Dr. Luz explained, "We need sufficient genetic diversity. So it's important to work towards the big goals set out by the Convention on Biological Diversity. For mammals, that's a minimum of 100 founders."
Researchers around the world are also taking similar measures. Universiti Putra Malaysia successfully extracted sperm from 15 Sunda pangolins in 2020, and in July 2024, scientists at the Guangdong Academy of Forestry in China collected and analyzed sperm from the critically endangered Chinese pangolin (Manis pentadactyla). Dr. Luz expressed hope that this research will continue, adding, "We can collaborate to build a more comprehensive population safety net."
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