Why Can’t We Clone Endangered Species to Save Them?


Thanks to Skillshare for supporting this episode
of SciShow. [♪ INTRO] Tigers, gorillas, rhinos, it seems like there are a lot of animals on the
endangered species list these days. But we know how to clone animals. So if the problem is too few rhinos, and if
we know how to make more rhinos, problem solved, right? Well, there actually are people working on
cloning endangered animals. But, it is not as easy as you might think,
and in the end, it still won’t fix the problems that made those
species endangered in the first place. The first mammal cloned from adult cells was
Dolly the sheep back in 1996, and since then scientists have cloned a lot of different
things, like cats, dogs, and even monkeys. And it didn’t take long for endangered animals
to get on that list. In the early 2000s, for example, researchers
cloned a type of wild cow called the gaur. And they went on to clone other endangered
cattle, wild sheep, and even an extinct wild goat. But, as cool as these achievements were, none
of them ended up really increasing the species’ numbers. That’s because, despite what movies might
suggest, you can’t just order up an army of clones. To clone something, you typically need more
than just some DNA from the original creature. You also need an egg cell to put that DNA
into to create an embryo. Then that embryo needs to be implanted in
a surrogate mother to develop. You can’t just do this in a petri dish. While that all might sound straightforward enough, getting those eggs in the first place
can be difficult and risky for the animal. To know how to get eggs, you need to know
a lot about that specific animal’s reproductive biology, like when they ovulate, or grow and
release egg cells. Humans generally ovulate in regular, frequent
cycles, but not all animals do. Pandas only ovulate once a year, for example, and there are animals like cats
that only ovulate after mating. We can sometimes use hormone
injections to kick start ovulation, but each animal may need different
doses or a different mix of hormones. And then you still have to get the eggs.
Take rhinos, for example. Like, you try convincing a 1,700 kilogram
ovulating rhino to let you collect eggs from inside her using a custom-designed,
one-and-a-half-meter-long device. I won’t. I mean sure, you can sedate her.
Which is definitely what the researchers do. But sedation also carries risks. All and all, getting eggs from animals may
involve multiple hormonal injections and the use of anesthetics
or surgical procedures, and not every individual animal is
healthy enough to undergo all that. And also, you need to collect a lot of eggs. The DNA-egg cell fusion doesn’t always
work right, so for each viable embryo, you might need hundreds of egg cells. And even if you go through all of that, you
still need surrogates to carry the pregnancy. Like collecting eggs, that requires knowledge
about the animal’s reproductive biology, as well as lots of healthy female animals; more than
just the number of clones you want to make. Because unfortunately, not every implantation
takes and develops into a healthy offspring. For plentiful species, or ones we know really
well, like cows or sheep, those might not be big problems. But for endangered species, like tigers or rhinos, there
may not be enough female animals to work with. The good news is that
there are ways to kind of cheat. You can sometimes use eggs or mothers from
more common, closely related species, for example. The baby gaur’s surrogate mom was actually
a regular cow named Bessie. Because, of course, all cows
are named Bessie, apparently. But hybrid embryos can have
extra problems during development. Scientists are working on an alternative to
all this: a way to make eggs and sperm by genetically reprogramming
frozen tissue samples. So one day we might be able to make a lot of
eggs without needing a lot of female animals. But that’s still in the very early stages
and the process will likely need to be customized for each animal. Now, it’s possible that we might figure
out how to solve all of these challenges. But even if we could clone any animal we wanted,
it might not be the fix we were looking for. For one thing, even though cloning might increase
the number of animals, you could still end up with a loss of genetic diversity because
they’d all be genetically identical. That’s bad because the population could
effectively become inbred, which can leave them vulnerable
to diseases or genetic disorders. If you have frozen tissues from a lot of different
individuals, you might be able to avoid this issue or even reintroduce
genetic variation that’s been lost, but that will depend on what you’ve stockpiled. The real problem with cloning endangered animals
is that it won’t stop the poachers, habitat loss, or myriad other things driving these
species extinct in the first place. Cloning is very expensive, and some researchers
have pointed out it’s probably cheaper and more effective to spend that money on fighting
poaching, creating new nature reserves, or other, more traditional conservation efforts. Still, scientists working on cloning remain
optimistic that it could one day become a really useful tool for conservation, like
to reintroduce lost genes or a last lifeline to save species whose numbers
have dwindled to just a handful. But for now, we’ll have to make all of our
tigers and rhinos the old fashioned way. Cloning animals in the real world: super tricky,
but cloning pictures of animals is something anyone can learn to do well,
especially with a little help from one of the amazing Photoshop
classes offered by Skillshare. But if you really want to up your Photoshop-art
game, you might want to check out this Skillshare course by lifestyle journalist Helen Bradley
on how to make surrealist collage effects. In it, Helen explains how you can use different
Photoshop tools to split apart an image and make really wacky art, sort of like the prints
by the artist featured in the episode, Julia Geiser. What I love about this class is that, as the
title suggests, Helen goes through everything clearly and quickly, so you really can take
the class over your lunch break! And Helen has a bunch of other
quick courses on Skillshare, so you can try your hand at making
stylish doodles or drawing furry creatures. Right now, Skillshare is offering SciShow
viewers 2 months of unlimited access for free. And they have more than
20,000 classes to choose from, so no matter what hobby you want to pursue,
there’s probably a Skillshare course for you to take. And you’ll be supporting SciShow while you do it. You can follow the link in the description
to check it out! [♪ OUTRO]