- Scientists in Singapore have decided to collect and freeze sperm from pangolins to use in future artificial insemination programs for the threatened mammals should the need arise.
- The eight known species of pangolins are collectively the world’s most trafficked mammal. The Sunda pangolin has seen its population decline by over 50% in the last 15 years.
- All pangolin species are listed as threatened, and scientists say they hope to create a reservoir of genetic material before arriving at a “too little, too late” scenario.
- While it has successfully extracted and stored sperm from 38 pangolins, the Singapore lab hasn’t collected egg cells from female pangolins because the procedure is much more invasive.
SINGAPORE — A cloud of condensation rises as Shangari Sekar, the assistant laboratory manager for Mandai Wildlife Group, carefully lifts a ladle filled with vials from the center of a cryo tank. She moves slowly as the cargo is precious: within the vials are the genetic building blocks for pangolins, the most trafficked mammals on Earth.
With the future looking bleak for these scaly anteaters, scientists have launched a pangolin biobank to help ensure they live on. Dr. Sonja Luz, CEO of Mandai Nature, the wildlife group’s conservation arm, says they’ve taken this step to create a safety buffer: “We are really worried we are getting too many ‘too little, too late’ scenarios.”
There are four known pangolin species native to Asia and four to Africa, and all populations are declining. Poaching and habitat loss have pushed all eight species into the threatened category on the IUCN Red List. Singapore is home to the critically endangered Sunda pangolin (Manis javanica), which is also found in Cambodia, Indonesia, Laos, Malaysia, Myanmar and Vietnam.
“The Sunda pangolin has seen its population decline by over 50% in the last 15 years due to high levels of poaching driven by the illegal wildlife trade,” says Uma Sachidhanandam, director of conservation and science for WWF in Singapore.
The international trade in wild pangolins is banned under CITES, the global wildlife trade convention. Singapore also strengthened its own endangered species act in 2022, with traffickers now facing fines of up to S$100,000 (about $74,000) per specimen as well as a six-year jail term.
In urban Singapore, the Sunda pangolin’s biggest threat is vehicle traffic. Yet, as a global transit hub, Singapore is acutely aware of the effects of the poaching industry. In one six-day period in April 2019, Singaporean authorities seized nearly 26 metric tons of pangolin scales with an estimated value of $77 million, intercepted en route from Nigeria to Vietnam.
The Mandai Wildlife team first began biobanking 10 years ago when they started helping to conserve another threatened species, the giant panda (Ailuropoda melanoleuca). To support their IVF and endocrine work, they created a lab filled with freezers and cryobanks at the wildlife hospital, part of the Mandai Wildlife Reserve that also hosts Singapore Zoo.
Mandai had six pangolins of its own, and more than 30 wild pangolins typically pass through its doors each year for rehabilitation before being released into the forest. This offered the opportunity to help protect another species, and staff duly started taking pangolin samples in 2016.
When a pangolin is brought to the wildlife hospital, the team carries out a full health check, including blood work and ultrasound, under general anesthesia. For males, they also take semen; for now, they’ve chosen not to take oocytes (eggs) from the females.
“Harvesting of semen under anesthesia is completely harmless to the animal. [Removing eggs] is very invasive. You have to do that endoscopically. We want to always make sure we are not compromising welfare in whatever we do,” says Luz, a trained wildlife veterinarian.
They did attempt to remove oocytes from dead pangolins, but were unsuccessful. They also realized they wouldn’t be able to process and store the eggs with the equipment they currently have.
The team remove the semen manually or by electroejaculation. During the electroejaculation process, a small device is inserted into the pangolin’s rectum and positioned near the prostate gland. Electrical pulses then stimulate the gland and cause ejaculation. The process is commonly used in domesticated animals and has also been used to bank sperm from men with spinal cord injuries and other health conditions.
Once staff have retrieved semen from the pangolin, they have a matter of minutes to complete the biobanking procedure as the semen is sensitive to temperature. Fortunately for the wildlife hospital, its laboratory and biobank are under the same roof.
However, before they bank it, veterinarian Charlene Yeong says they analyze each sample to check whether it’s complete and how mobile it is.
The team also pioneered a new technique to help deliver oxygen to the anesthetized pangolins. As the animal’s breathing apparatus lies deep within its mouth, they initially used a mask over its cone-shaped head to deliver the oxygen. But then they fine-tuned the process by creating a tube system that would make the gas flow more precisely. “Gas delivery through a mask is not as easily regulatable, [but with] intubation you control the oxygen flow much better,” Luz says.
The researchers also created another world first for pangolins. Apart from collecting semen from live pangolins, they also collect skin cells from pangolins killed in traffic accidents to grow fibroblasts (a type of biological cell). These fibroblasts can be reactivated into stem cells, potentially forming an embryo when introduced into an egg.
Dan Challender, who is based at Oxford University in the U.K. and has been involved in pangolin research and conservation for 15 years, says: “I think biobanking pangolin sperm could have potential application for conserving the species in the future. But I hope that we don’t need it because we’ve been able to identify the key threats to the species and taken action to ensure healthy populations of pangolins in the wild.”
Mandai Wildlife Group has bred three pangolin pups by bringing breeding pairs together. It hasn’t yet used the pangolin sperm for artificial insemination, collecting it for research and for use in future assisted reproduction should the need arise.
Luz says breeding pangolins naturally is ideal. However, she says it’s important to master artificial techniques now, pointing to the case of the northern white rhino, which is functionally extinct now that there are only two females remaining. “If you get into situations where you just don’t have enough individuals left to [breed], then … it’s too late,” she says.
The goal for the pangolin biobank is to build capacity. It now has samples from 38 pangolins. “You need enough genetic diversity. So really working towards also these big targets that are set by the Convention on Biological Diversity. For mammals you need at least 100 founders,” Luz says.
Researchers around the world have also taken similar steps. Putra Malaysia University carried out the successful extraction of semen from 15 Sunda pangolins in 2020, and in July 2024, scientists at China’s Guangdong Academy of Forestry collected and analyzed sperm from the critically endangered Chinese pangolin (Manis pentadactyla). Luz says she hopes this type of work continues.
“We can work together on a more holistic population safety net,” she says.
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Editor’s note: This story was modified April 11 to correct the description and clarify the use of fibroblasts.
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