there are several of them weird stuff in Shrek 2 – the sequel to DreamWorks’ surprising hit about an ogre falling in love with a princess.
Amid royal frogs, ogre farts and angry in-laws in Shrek 2, there’s one detail that’s arguably stranger than the rest: the tumultuous love affair between Shrek’s best pal, Donkey, and Dragon. At the end of the film, it is revealed that Donkey and this dragon have mated, producing six flying donkey-dragon hybrid creatures called “dronkeys”.
It may seem like just a stupid plot point in an already very stupid movie, but this strange donkey-dragon relationship actually reveals a serious scientific debate about the biology of hybrid animals and their role in the animal kingdom.
But could a donkey and a dragon really – well, hypothetically, since dragons aren’t real – mate and produce babies? According to Scott Taylor, assistant professor, Department of Ecology and Evolutionary Biology at the University of Colorado, the answer is a firm no.
“Two species as different as a donkey (mammal) and a dragon (reptile?) could never produce offspring,” Taylor said. Reverse.
Still not convinced? Let’s take a closer look at the science of bumblebees.
Coil Science is a Reverse series that reveals the real (and fake) science behind your favorite movies and series.
What are hybrid animals?
Many scientists interpret “hybrid” to mean a cross between two different species – sperm from one species uniting with an egg from another species – resulting in an offspring with a 50/50 mix of genetic information from both. species. Some common true hybrids are mules, ligers, coywolves, and tigons.
So the bumblebees in Shrek 2 would like to definitively be hybrids. But hybrids can technically form even when two animals of the same species mate, as long as they belong to genetically different populations or subspecies. A hybrid could result from two different dog breeds – what we commonly call a “mutt”.
“A hybrid is the result of a cross between two different forms,” says James Mallet, professor of organismal and evolutionary biology at Harvard University. Reverse.
But Mallet explains how the boundary between hybrid and non-hybrid can very quickly become blurred over successive generations:
“A first-generation offspring of two species (like the dragon-donkey ‘dronkeys’ hybrids in the Shrek movies) is clearly a hybrid. But if those hybrids interbreed with one of the parent species, when does it stop d be a hybrid and start to be the recipient species with some genes from another species?”
Hybrid animals are different from so-called “chimeras,” which are “created when cells from one animal are transferred into another animal,” says Insoo Hyun, director of research ethics and faculty member of the Harvard Medical School Center for Bioethics. Reverse. A human receiving a transplant from another human would technically be a chimera, but not a hybrid.
Hybrid offspring resulting from interspecific breeding were previously thought to be uncommon in animals compared to plants, but “scientists are now realizing that this happens much more than previously thought,” Eva- Maria Geigl, paleogenetician and director of research at the Jacques Monod Institute in Paris, tells Reverse.
There has even been some debate over whether humans are hybrids due to the prevalence of Neanderthal DNA among many of us. But it wouldn’t be accurate to call humans hybrids, experts say.
“Humans are not hybrids, but there is evidence of hybridization in our evolutionary history – (yes, with Neanderthals)”, Taylor said.
In theory, researchers could create human-animal hybrids in a lab “by uniting sperm and eggs from closely related humans and apes,” according to Hyun.
But Hyun also adds, “There’s no scientific reason to do it, and I don’t know anyone who actually thinks it should be done.” Thus, there will probably be no human-ape babies in the near future.
Can a donkey and a dragon have babies?
In short: no. While dragons are fictional, we can assume for our purposes that dragons are a derivation from reptiles.
“Hybridization requires that the two species/subspecies are close enough for the offspring to be viable and that they are both able to meet,” said Alexandra Palmer, researcher at the The School of Biological and Social Sciences at the University of Auckland tells Reverse.
The donkey and the dragon fulfill this last condition – proximity – but not the first. Reptiles are do not closely related to mammals, ergo, mating – and hybrid offspring – between an equine like Donkey and a reptile Dragon shouldn’t be possible, even in a fictional world where ogres exist. Mallet jokingly rates the chances of success of a cross between a donkey and a dragon as “one in ten billion”.
“A hybrid between donkeys and dragons is a fantastic idea since dragons are (presumably) egg-laying reptiles and not mammals like donkeys,” Hyun says, adding, “They would be too far apart. evolutionarily different for this combination to work.”
Palmer agrees. “In the real world, certainly no reptile could successfully interbreed with an equine,” she says.
“A hybrid between donkeys and dragons is a fantastic idea”
But even if Shrek 2‘s Donkey managed to mate with another non-dragon species, his offspring could very well be sterile.
In the real world, donkeys are not hybrid animals, but they can mate with horses to produce hybrid offspring, called mules and hinnies. Hinny are the offspring of male donkeys and female horses, and vice versa for mules. Mules and hinnies are both sterile, meaning they cannot reproduce naturally.
“The closer in evolution a hybrid’s parents are, the higher the chance that the hybrid will be able to produce its own offspring,” Hyun says.
Are hybrid animals good for the world?
Compared to human-animal chimeras, there are generally fewer ethical issues regarding hybrid animals – such as zonkeys or mules – especially those bred by humans.
“Farmers have been creating hybrids for centuries, so the hybrids aren’t shocking or novel in a socially disruptive way,” Hyun says.
But there are also concerns about whether the hybrids are evolutionarily good. Conservationists often worry that non-native hybrid animals introduce invading genes and wipe out a local species.
“We are almost always concerned about the short-term survival of species in conservation, so we don’t want to mess them up with invasive genes,” Mallet explains.
While some scientific reports suggest hybrids may contribute to species loss, other studies suggest they may be beneficial in adapting to circumstances such as climate change by introducing new DNA into a local population. . Recent reports suggest that polar bears are mating with grizzly bears to form “pizzly bear” hybrids due to climate change.
“Whether hybridization is good or bad depends on the context,” Taylor says.
Taylor offers an example of humans introducing a non-native species – say, rainbow trout to Colorado. This species could “hybridize” or breed and form offspring with a native species like cutthroat trout, potentially leading to species loss.
“But hybridization can also provide genetic variation that selection can act on to produce new species – for example, Lake Victoria cichlids – or allow species to adapt quickly to change,” Taylor adds.
Mallet agrees. “Hybridization is a natural process and is neither ‘good’ nor ‘bad’. That’s right,” he said.
Whether good or bad, hybridization is here to stay – both in the real world and in the imaginary world of Shrek 2.
Shrek 2 is streaming now on Netflix.