Everything Everywhere Daily: History, Science, Geography & More - Rat Eradication on South Georgia Island (Encore)

Starting point is 00:00:00 The following is an encore presentation of Everything Everywhere Daily. Humans and rats have lived in an uneasy relationship for millennia. Rats have spread diseases like the bubonic plague, destroyed grain harvest, and stolen our pizzas. In return, rats have given humans, well, pretty much nothing. As such, humans have waged a relentless war against rats, which, for the most part, has gone nowhere. However, there are some fronts where we have had some amazing success. Learn more about humanity's war on rats. on this episode of Everything Everywhere Daily.

Starting point is 00:00:36 What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night. And how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. The history of rats and humans goes back to the beginning of agriculture. The rats, which most humans are familiar with, are the black rat or the ship rat, which came from India, and the brown rat or the Norwegian rat, which, oddly enough, didn't come from Norway, but somewhere else in continental Europe. Prior to the rise of agriculture, there was nothing special about the rat human relationship.

Starting point is 00:01:36 Rats were like other rodents that lived in the wild. They were opportunistic eaters and were preyed on by larger carnivorous mammals and birds. With the rise of agriculture, rats found a brand new, almost unlimited food source, grain. Humans produced tons of grain, and all the rats had to do was hang around humans, and they could get almost unlimited food. Rats are omnivorous, which means they can eat almost anything. Grain, fruit, meat, insects, and other rats are all on the menu. Almost immediately, this caused problems for humans. Many early farmers had their entire crops wiped out due to infestations of rats.

Starting point is 00:02:13 It's widely believed that the rat's attraction to human settlements was one of the major reasons for the domestication of cats. As rats came for our food, the cats came for the rats, but that's a topic for another episode. Even today, an estimated 1% of all cereal crops in the world are destroyed by rats, and as much as 5% in some developing countries. Rats were widely thought to be the transmission mechanism for the bubonic plague, which was behind the Black Death and the Plague of Justinian, and you can see my previous episode about that. As humans spread across the globe, rats came with them every step of the way. This was also true when humans started to go on long ocean voyages. Rats would board the ship where they would survive by eating food stores and then would leave the ship once it arrived in a new port. And this gets to the subject of this episode.

Starting point is 00:03:02 Ships spread rats all over the world. In the old world, rats were annoying and were pests, but they didn't overload the ecosystem. However, many of the islands that the rats wound up on had no defenses against them. They were nesting areas for numerous seabirds and had no natural predatory. Because these islands were isolated and didn't have any natural predators, birds would set their nests right in the ground and in large numbers. These birds, and more importantly the bird eggs, were easy prey for rats. Rats have done more to devastate the population of seabirds than anything else in the world. One island in particular had been hit very hard from rats, South Georgia Island. If you aren't familiar with South Georgia Island, I can tell you from firsthand experience that it is one of the most

Starting point is 00:03:47 incredible places on earth. Located between South America and Africa, north of Antarctica, but everything is north of Antarctica, it's a British territory and one of the largest breeding grounds for penguins and seabirds in the world. Well, at least it was. In the early 20th century, Norwegian whalers and sealers set up bases on the island, and with them came rats. The rats, facing no natural predators, destroyed the native population of albatross,

Starting point is 00:04:14 scuwa, turns, and petrels. Most importantly, the two species of bird which were found nowhere else in the world, the South Georgia Pippet and the South Georgia Pintail, were threatened with extinction. It had been estimated that by 2010, the seabird population on South Georgia was probably 10 million less than what it would have been if there were no rats on the island. In 2010, the British government announced their intent to eradicate rats on South Georgia. South Georgia Island isn't enormous, but it was going to be the single largest rat eradication program in the world.

Starting point is 00:04:48 The hard part of getting rid of rats is that you have to get rid of all the rats. Killing 99% of the rats won't work. It has to be 100%. Rats reproduce rapidly. Really rapidly. A female rat can have six litters in a single year, and a rat can reach sexual maturity only nine weeks after being born. If you have two rats, absent any predators or food shortages, you can have a half a

Starting point is 00:05:15 billion rats within three years. The good thing about South Georgia is that the center of the island is mostly covered in ice. The island is also surrounded by various peninsulas and fjords, which meant that the different parts of the island were separated from each other by ice, and rats can't cross over ice. The plan was to cover the rat-infected parts of the island with a rodenticide called rhodophicum. The poison is an anticoagulant that causes the rats to bleed internally and die. The poison-laced rat pellets were methodically spread by helicopters, which carried bins of pellets that spread the pellets below them. They would fly a route that was plotted via GPS to make sure that they got every square inch of the island. If they missed anything, a few rats might survive, and the entire project would be for naught.

Starting point is 00:06:02 Now, if you're like me, you might be wondering if spreading all the poison around might not harm the birds. And the answer is, yes. but the impact on the birds wouldn't be nearly as bad as what it would do to the rats, and the impact would be short term. In the long term, the birds would thrive once the rats were gone, and the poison in the rat pellets would decay over time. This technique had been tested on other islands, where the rats were eradicated and the birds came back. The first test was done in 2011. The next season, they laid traps to find evidence of rats and found nothing. Phase two commenced in 2013, and phase three in 2015.

Starting point is 00:06:39 In total, more than 300 tons of rat poison were spread over the island. You just can't declare victory when it comes to rats. They set traps and brought in rat sniffing dogs to the island in 2016 and 2017 to check to see if any rats had returned. In 2018, the South Georgia Heritage Trust announced that South Georgia Island was rat free. It was the largest successful rat eradication program in history. There has already been a noticeable increase in the population of the South Georgia's a Pippet, which is the only songbird in the Antarctic and sub-Antarctic region. The sound of the pippets is now said to drowned out the sound of the seals.

Starting point is 00:07:18 They've instituted protocols for the ships which visit the island to make sure that no rats ever return. Ships are fumigated and checked with rat sniffing dogs. Other islands around the world have looked to the success of the rat eradication on South Georgia and are looking to replicate the success themselves. Hopefully, this will be the start of removing the invasive rats which were brought to many of these islands by humans and the return of the native birds which live there. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Thor Thompson and Peter Bennett.

Starting point is 00:07:53 I just want to thank everyone, including the show's producers, who support the show over on Patreon. If you'd like to support the show, just head over to patreon.com, which is currently the only place where you can get show merchandise. Also, if you want to talk to other listeners about the show, head over to our Facebook group or Discord server, both of which have links in the show notes.

Everything Everywhere Daily: History, Science, Geography & More - Rat Eradication on South Georgia Island (Encore)

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