eli5: Why is it so difficult to mate endangered species and increase their populations in the same way we mass produce cows and chickens
In: Biology
Domesticated animals like cows have been selectively bred and although it’s not the primary trait farmers have looked for the selective breeding has included a tolerance for human proximity, so can be readily bred on farms. Their habitat is also one that is commercially viable to provide – pasture – because were farming the animals.
Many wild animals have a low tolerance for proximity to animals they perceive as threats – and humans certainly qualify here. Captivity, particularly with close human proximity, puts stress on them that discourages reproduction. Large wild animals (eg rhinos, pandas, etc) also have a strong preference for a large habitat. If they don’t believe their habitat needs are being met they won’t breed. Further – if bred it is often challenging to release them into the wild, as the primary factors for why they are endangered are:
1. Loss of habitat, mostly due to humans.
2. Poaching, entirely due to humans.
Lost habitat has been lost because we’ve taken it for other uses. And animals that get poached are still highly targeted by poachers. So even if we could mass breed them it would be extremely challenging to repopulate wild populations as there’s nowhere to put them and even when there is people frequently kill them.
Then we come to captive populations – many of these animals are very resource intensive to maintain in captivity so have to be commercially viable within the budgets of zoos, which are often very tight. Zoos flatly cannot afford to mass reproduce them.
Because you need an animal which can live in the wild, so you can’t just put them in captivity and later release the offsprings, they would die.
Said this not every animal can be held captive. Some just don’t easily breed in captivity, others literally die in captivity like great whites
Most animals don’t take well to being locked up in captivity, they don’t breed, they don’t eat, they kill themselves trying to escape… They won’t raise their own offspring…
Another problem is that the natural territories of these animals are in other countries, and they are low on their governments’ list of priorities. So for example laws against poaching aren’t enforced because the government doesn’t have enough funds to allocate to that; they have too many other issues in their country that need funding.
There are a few different reasons that can apply situationally.
While any animal can in theory be kept and bred in captivity if we provide it with a perfect enclosure, that isn’t always possible. Sometimes the perfect enclosure would simply be unreasonably expensive to build, such as with large whales, but more often its because we are missing some crucial information about some subtle element(s) the animal needs.
Great white sharks for example are incredibly hard to keep alive in captivity, even though the much larger whale shark is not only possible to keep alive in captivity, but actively thrives! This is because whale sharks despite their size live in relatively shallow and tropical areas that are easy to replicate in captivity. Their social behaviour is also very easy to research partly because it’s easy to keep them alive in the first place and partly again because they live in places we can easily observe them, making even their abstract needs easy to meet.
Great white sharks however are found in a wide range of areas, including a wide range of temperatures and water depths. We really don’t understand exactly when and how they require (or even if they require) access to different kinds of habitats.
There is also sometimes political pressure on obtaining the animals in the first place. Giant pandas are the prime example here, as they are “claimed property” of the Chinese government. You “can’t have pandas” unless the Chinese government says you can, and they don’t exactly loan them out for free.
Other examples include animals that live in very poor areas that can’t afford to provide them with protection or proper captivity, but also refuse to let foreign organizations take them.
Money and public support are the two biggest factors. Just about any animal could be protected and allowed to breed naturally with an unlimited amount of funding, but for the most part no one is going to spend billions of dollars buying and protecting a massive reserve to keep the animals safe. Because of that, these programs need to use their much smaller budgets to keep the animals safe on public lands.
The US red wolf recovery program is a perfect example of how this can fail. There’s a huge network of zoos and wildlife centers breeding them in captivity to ensure they don’t go extinct. Yet, none of that matters if there’s nowhere to *put* the wolves. The only wild population known is in South Carolina after being reintroduced there in the 70’s, and the local government has made it repeatedly clear since that they no longer want the wolves around. They do everything they can to hinder additional reintroductions, while simultaneously looking the other way as local landowners illegally kill them.
Without somewhere for the wolves to live in the wild, there’s only so much a breeding program can do.
Sometimes the population is so small that you end up with indbred offspring.
This happened with cheetahs: their population numbers underwent a sudden drop in the past, introducing what is known as a genetic bottleneck. Since so much of the population died, there is less genetic variation in the species, leading to an increased chance for harmful mutations appearing in offspring.
This is made worse by human activity (hunting, habitat loss), which further reduces the genetic variance of cheetah populations.
Latest Answers