Dog cloning. You’ve probably heard about it. Barbra Streisand certainly has, and she’s not alone. And if we’re being honest with ourselves, who hasn’t looked at a beloved dog and wished for more time? The grief of losing a dog is real and is in no way trivial. But as a dog lover — not just a lover of one particular dog — would you actually want to look into cloning? 

Cloning is pretty much what your 9-year-old self thought: it replicates an individual’s genetic makeup, and tada(!), out comes a genetic clone. It sure seems like a straightforward, one-to-one process — take cells from a beloved dog, send them to a cloning lab, and get back your cloned BFF. But the “tada” part is anything but straightforward, and that’s where the animal welfare concerns arise. 

In 1996, Dolly the sheep became the first cloned mammal. Since then, cloning took off, sort of. Mice, cows, pigs, goats, rabbits, and cats were relatively easy to clone, but a multi-million-dollar project out of Texas A&M to clone a dog in the late 1990s — the Missyplicity Project— did not produce another Missy. As reported recently in Scientific Reports, “What made dog cloning challenging was certain unique aspects of the reproductive process in canids compared to most other mammals.” Dogs have a more limited breeding period, and it can also be difficult to extract their eggs, a necessary step in the cloning process. 

The first cloned puppy, Snuppy, an Afghan hound, was born in 2005 at Seoul National University using somatic cell nuclear transfer (SCNT). In this technique, eggs are removed from female dogs, the nucleus is removed (enucleated), and body cells from the to-be-cloned dog are injected into the eggs. The eggs serve as host for the genetic material of the dog to be cloned. Electric stimulation makes the egg divide, and divide, and divide to behave like a growing embryo, and eggs are then implanted into a dog who serves as a surrogate. The history of dog cloning shows common use of multiple surrogates.

The protagonist of the dog cloning story is not the cells to be cloned or even the cloned dog. Instead, the unseen protagonists are the dogs behind the scenes giving one dog’s cells a new run at life. Cloning research — and the cloning of any beloved pet dog — relies heavily on female dogs. Not only for their eggs, but also as surrogates to birth the clones. In the cloning business, these dogs are housed for the purpose of egg extraction and implantation, with varying success rates.

To produce Snuppy, the first dog clone, over 1,000 embryos were surgically transferred to 123 surrogates, resulting in three pregnancies. Out of those three, one fetus miscarried, and two were carried to term — one clone had neonatal respiratory distress and died within three weeks, and the other became the world famous Snuppy. A 2008 paper described the cloning of a toy poodle by implanting 20 dogs — two became pregnant, and only one maintained the pregnancy to produce a live puppy by caesarean section. Of course, many more dogs were part of the early stages to figure out the just-so technique needed to clone a dog.

Over time, the number of dogs involved in the process seems to have decreased, but questions remain about the dogs involved and produced. How many dogs serve as egg providers and surrogates, and how many become pregnant? The quick turn around time advertised in pet cloning might suggest that more than one surrogate is used. And how many pups are born, and what happens to any “extras” produced? After all, the first commercially cloned pet dog, Booger, produced five cloned copies. 

I’ve been wondering for some time about the dogs behind the dog-to-be-cloned. In a 2015 interview, I asked John Woestendiek, a Pulitzer Prize-winning investigative reporter and author of the 2010 book, Dog, Inc.: How a Collection of Visionaries, Rebels, Eccentrics and Their Pets Launched the Commercial Dog Cloning Industry to weigh in:

“…there are concerns about the number of dogs it takes to clone just one. In addition to the tissue sample of the original dog, cloners will need to harvest egg cells from dogs in heat – maybe a dozen or so. And, after zapping the merged cells with electricity so they start dividing, they’ll need surrogate mother dogs, to carry the puppies to birth. That’s a whole lot of surgeries, on a whole lot of dogs.

“Add to that all the cases that go wrong, all the aborted fetuses, all the dogs that don’t come out as exact matches, and an argument can be made that dog cloning is not only adding to the dog overpopulation problem, but causing a lot of pain and suffering along the way.”

Cloning regulations and oversight aren’t entirely clear either. As Woestendiek reports in Dog, Inc.,“While research companies and universities receiving government funding for projects are required to submit to U.S. Department of Agriculture inspections and to report the number of cats and dogs they use, pet cloning companies are not subject to federal or state licensing, and are not required to either uphold standards of care or keep records on how many animals they use” (p. 218).

Then there is clone quality. Even if the original dog was healthy, clones are not immune from deformities and abnormalities, even if not frequently reported. A 2014 report described two clones of an 8-year-old male German shepherd; one pup was healthy, while the other had a cleft palate and abnormal external genitalia. A 2015 report described anomalies of the liver and gallbladder resulting in day-of-birth death of the cloned puppy. Cloning of the clone (yes, that’s called recloning) did not produce the abnormalities in the resulting pups (yes again, the reclones). As Viagen Pets — which describes itself as “America’s Pet Cloning And Genetic Preservation Experts” — reports, “Unfortunately, all forms of reproduction result in some unhealthy births.” While they add, “Regular health checks are performed on animals to ensure the health and wellbeing of the animals,” I, for one, welcome more specifics on this topic.  

Dog cloners, and increasingly the general public, understand that clones are not always physical matches of the original. One genotype can produce a diversity of phenotypes, the outward physical appearance. After all, the first cloned cat named Carbon Copy (CC) looked nothing like the original, highlighted veterinarian Sophia Yin in an interview with geneticist Leslie Lyons: “The cool thing about CC is that it shows that even though two animals are genetically identical, they may not look or act identical. A clone is never actually identical because there are so many different environmental factors that come into play.”

And perhaps of most importance to pet owners, pet cloning companies increasingly admit that clones do not match the original pet’s personality. “The new puppies and kittens will be the same sex as the donor, but just as it is in nature, may have slight phenotypic differences, such as different markings due to natural epigenetic factors,” reports Viagen Pets FAQ. “The environment does interact with genetics to impact many traits such as personality and behavior.”

In fact, cloning a personality is virtually impossible. In a 2013 interview with me at The Bark, Samuel Gosling, a personality and social psychologist, explained: “Temperament is the basic, biologically inherited tendencies of an individual, and personality is the result of the interaction between temperament and the environment.” Because environments are never purely identical, even in lab conditions, cloning an original’s personality, by definition, would be impossible (unless there are parallel universes). 

And yet… Stay. Please don’t go. 

Who hasn’t made these simple requests to a dog. How could you not? What I wouldn't give to bring back “the original.” Even apart from the welfare issues, cloning can’t live up to our ideal.

“Cloning does not buy immortality; it is not cheating death,” reminds philosopher Mark Greene. “Cloning is no more a way to extend the life of an individual animal than having a genetically identical twin is a way for one individual to live two lives simultaneously — twins are distinct individuals, and so are clones.”


Greene M. (2002). New dog: Old tricks. Journal of Applied Animal Welfare Science, 5, 239-242. 

Jang G et al. (2008). A cloned toy poodle produced from somatic cells derived from an aged female dog. Theriogenology, 69, 556-563.

Kim M J et al. (2017). Birth of clones of the world’s first cloned dog. Scientific Reports, 7, Article number: 15235 

Kim G A et al. (2012). Species-specific challenges in dog cloning. Reproduction in Domestic Animals, 47, 80-83. 

Kim M J et al. (2014). Reduced birth weight, cleft palate and preputial abnormalities in a cloned dog. Acta Vet Scand. 56(1): 18.

Kim M J et al. (2015). Ectopic liver and gallbladder in a cloned dog: Possible nonheritable anomaly. Theriogenology, 84, 995-1002.

Woestendiek, J. (2010). Dog, Inc.: How a Collection of Visionaries, Rebels, Eccentrics and Their Pets Launched the Commercial Dog Cloning Industry. Avery, New York.