Researchers at the San Diego zoo were celebrating last week after one of their beloved southern white rhinos was determined to be carrying a rhino fetus. This rhino became pregnant after male white rhino sperm was injected into her uterus at just the moment that all the stars in the rhino universe aligned.
Artificial insemination with rhinos is hard. Calculating the estrus cycle of female rhinos is tricky enough. Add to that the sheer distance of the ovaries and uterus from where the artificial inseminator can enter the rhino’s body. In addition, as is often the case with very large mammals, rhinos are just not very prolific breeders. You need a little bit of guesswork and more than a little luck for fertilization to occur.
Two months after the successful procedure, the embryo visible on the ultrasound is still only an inch long. The normal gestation period for southern white rhinos of sixteen to eighteen months means that there will be plenty of room for nervousness in the weeks and months ahead. For now, rhino lovers around the world are keeping their fingers crossed.
Southern white rhino populations have recovered somewhat in the last century after their near extinction at the turn of the last century. Today there are thought to be around 20,000 of them worldwide and, while the population is still categorized as “near threatened,” their numbers are currently increasing.
You might wonder, then, why the first successful artificial insemination would be considered such an important milestone. Southern white rhinos appear quite capable of getting “horny”* with each other even without human technicians waving their catheters and syringes in the vicinity of the rhino’s sensitive parts. (*The “horny” pun, I have learned, is obligatory in stories about rhino breeding).
The answer, perhaps unsurprisingly, lies in the fact that the southern white rhino has the potential to be particularly useful to humanity. We want to borrow them for our purposes, or at least borrow their wombs.
Having failed to protect the last northern white rhinos from extinction, some scientists desperately want to make amends. Southern white rhinos, it is hoped, might serve as surrogate parents for a lab-generated embryos that could bring back their “functionally extinct” northern cousins.
Only two northern white rhinos still exist on the whole planet. Both of these are female. All northern white males are now dead, with Sudan, the last of his tribe, finally succumbing to old age the Ol Pajeta Conservancy in Kenya in March of this year.
Sperm from twelve northern white rhinos is waiting in freezers at San Diego’s Frozen Zoo for the opportunity to be defrosted and used in some variation of a resurrection project.
In one version of this endeavor, eggs would be extracted from the two remaining females and fertilized in a lab by the stored sperm. If things go well, the fertilized eggs would be implanted into southern white rhino females who would serve as stand-in mothers for the sixteen or more months that it takes to produce a baby rhino.
Such a feat would make the recent success with artificial insemination look like child’s play. On top of the mysteries of the estrus cycle and the low success of embryo implantation, simple geometry multiplies the challenges. Gathering the ova from the females, successfully fertilizing them, and then implanting them back into the uterus requires considerable ingenuity. It is also desperately invasive.
In the film, The Last Rhino, amid excruciating scenes of the scientists at work with a sedated female, it is pointed out that the five foot long probe used to withdraw eggs is inserted into the rhino’s anus (rather than vagina) due to the difficulties presented by the rhino’s anatomy. Success at this in vitro version of a fertility treatment is thought to be at least 15 years off.
This is why the procedure is being practiced in the relatively more numerous white rhinos first. These animals are experimental subjects for a technique that would not benefit them so much as their northern relatives. There is little point dipping into the finite stores of precious northern white rhino sperm if we are unsure of whether the experimental technique will actually work.
These pragmatic considerations bring into focus the complicated moral calculus at play in highly technological attempts to save – or even bring back from the dead – species that are imperiled (or already extinct).
On the one hand there are the countless millennia of evolutionary wisdom embedded in a species’ genome whose loss would be an unquestionable tragedy. An environmental philosopher named Holmes Rolston, III has called human-caused extinction “superkilling.” The end of a species represents a different order of bereavement from the end of an individual animal. If it were possible to prevent – or even undo – such a loss there would be ample moral motivation to explore this path.
On the other hand, one wonders whether the exploitation of one species to serve the interests of another doesn’t raise its own set of moral concerns. The website at the San Diego zoo declares that its staff “work closely with the rhinos, building positive relationships so the rhinos participate voluntarily in procedures like artificial insemination and ongoing monitoring of pregnancies.”
While one can only be extremely grateful for the hard work and dedication of those who commit their lives to the preservation of endangered species, the idea that southern white rhinos voluntarily submit to artificial insemination stretches credulity. Consent to invasive technological experiments is not that easy for rhinos to give.
Even though many large mammals appear to be much more warm-spirited and altruistic across species lines than the members of Homo sapiens that have imperiled them, some might balk at the methods under consideration. Viewed in a certain way, borrowing one species’ womb for the benefit of another can look like a form of “uterine hijacking.”
There also appears to be a risk that the ethical lens is being focused in the wrong place. The moral calculus should consider that it is the human inability to keep rhinos safe in their natural habitat that is the direct cause of southern white rhino uteri now needing to be borrowed.
As will increasingly be the case in the synthetic age, there is a distinct danger that the drama of an exciting technology might be used to obscure both an ongoing conservation failure (northern white rhinos) and a self-serving manipulation of another species (southern white rhinos).
I don’t offer an answer to this difficult conundrum. I’m pulled in both directions. The best we might hope for is that the discussion is informed, nuanced, and inclusive.
Ethics, as Aristotle suggested, is never a precise subject.
Rhino image by Paul Hudson (through Flickr) Test tubes by University of Liverpool Faculty of Health and Life Sciences (through Flickr)
Christopher J. Preston 