Sumatran rhinoIs there any hope of saving the Bornean rhinoceros (Dicerorhinus sumatrensis harrissoni) from extinction? Sadly, the chances of that happening seem to grow slimmer and slimmer. Experts once estimated that the rapidly disappearing forests of Sabah, Malaysia, could have hidden up to 10 Bornean rhinos–a subspecies of the critically endangered Sumatran rhino, of which fewer than 100 remain scattered around Borneo, Sumatra and mainland Malaysia. But this month Sabah’s environmental minister reported some devastating news: It appears that there are no more wild rhinos in the state.

There are, however, three Bornean rhinos in captivity in Sabah, all at the Borneo Rhino Sanctuary in Tabin Wildlife Reserve. One of them, a female named Iman, was captured from the wild a little over a year ago after she fell into a pit trap.

When she was rescued, Iman was proclaimed the species’s “newest hope for survival.” Sanctuary veterinarians even suspected she was pregnant at the time.

That didn’t turn out to be true. Ultrasound tests conducted soon after Iman’s arrival at the sanctuary revealed that the mass in her uterus wasn’t a fetus. It was a vast collection of tumors that would make it impossible for her to ever get pregnant naturally.

A male named Tam and another female, Puntung, also live at the sanctuary. According to WWF Malaysia, Puntung is also incapable of breeding because she has “severe reproductive tract pathology, possibly due to having gone unbred in the wild for a long time.”

So all hope is lost, right? Well, not so fast. Both Iman and Puntung are still producing immature eggs calls oocytes. It might be possible to combine those oocytes with Tam’s sperm to produce embryos in the lab, which could then be implanted back into one of the two females or a rhino of another species. Late last month the Malaysian government pledged about $27,700 toward financing artificial insemination techniques for the task. That’s just a fraction of the money the Borneo Rhino Alliance says it needs for the task, but it’s a start.

Meanwhile, there’s still a small chance that a handful of Bornean rhinos remain elsewhere on the island. Borneo is divided into three countries: Malaysia, Indonesia and Brunei. In 2013 video camera traps spotted one or more rhinos in the Indonesian province of East Kalimantan–the first such evidence of the subspecies there in many years. Most reports identified these as Sumatran rhinos because with so few animals left it hardly made sense to keep referring to the nearly nonexistent Bornean subspecies.

In fact, in 2013 the Sumatran Rhino Crisis Summit agreed to treat all Sumatran rhinos as a single species instead of a species and subspecies in order to maximize the potential for saving the greater species as a whole. Sanctuary officials told Mongabay last week that it’s time to bring together the world’s nine remaining captive Sumatran rhinos–including the three in Sabah–plus as many as can be gathered from the wild as possible in a last-ditch effort to save the entire species from extinction. Unfortunately, Indonesia has reportedly resisted efforts to find and capture its remaining wild rhinos. Until that happens, the chances of saving any of these rhinos from extinction rest on just a few captive animals, none of which are breeding.

The clock is ticking. In the past few years we have already lost the western black rhino in Africa and the Javan rhino subspecies in Vietnam. Without immediate help, the Bornean and Sumatran rhinos may not be far behind.

Previously in Extinction Countdown:

Photo by Willem v Strien. Used under Creative Commons license