TED Talks · Level C2 Mixing

How Rats Conquered The World

On a grey London day in 1851, a captivated crowd gathered around a makeshift stage.

Level: C2 · 77 sentences

Transcript

  1. On a grey London day in 1851,
  2. a captivated crowd gathered around a makeshift stage.
  3. At the center stood a man adorned in a top hat,
  4. leather sash, and a swarm of rats.
  5. This showman, Jack Black,
  6. had risen to fame claiming to be Queen Victoria's authorized rat catcher.
  7. And between tricks, he lectured the crowd on his poisons
  8. and unique ability to capture hundreds of vermin with just his bare hands.
  9. This is just one of many junctures in the long entangled history of human and rat.
  10. The two most common species of rat, brown and black,
  11. both scurried onto the scene roughly 1 to 3 million years ago in Asia.
  12. There, they craftily survived Earth's most recent ice age,
  13. and eventually, began living around and with humans.
  14. Their constant presence even earned them a spot in the Chinese zodiac,
  15. where they symbolize new beginnings.
  16. Brown and black rats are generalists,
  17. a biological badge ascribed to species who can brave diverse climates and diets.
  18. So when trade routes opened between East Asia and the West,
  19. rats naturally tagged along.
  20. Black rats were the first to venture out,
  21. sneaking aboard ships from India to Egypt
  22. an estimated 5,000 years ago.
  23. Some believe that this rodent influx into Egypt
  24. fueled their ancient spiritual reverence of cats.
  25. After all, they were top-of-the-line rat catchers.
  26. Trade between Egypt and the Romans brought black rats to Europe.
  27. These stowaways claimed lands as far as the Anglo-Celtic Isles,
  28. earning notoriety along the way.
  29. Beyond pilfering and reproducing like there's no tomorrow,
  30. black rats brought bacterial and viral infections,
  31. which they spread to humans through their droppings and urine.
  32. In the late 1340s, history's most infamous plague, the Black Death,
  33. killed tens of millions of people,
  34. or around half of Europe's population.
  35. To this day, many lay the blame on rats.
  36. However, the real story is more complicated.
  37. Black rats don't directly spread the plague to humans;
  38. though they can carry the fleas that transmit the bacterium responsible.
  39. And brown rats, which hadn't yet set foot in Europe,
  40. don't have any blood on their paws.
  41. Back in Japan, these brown rats were receiving a warmer welcome
  42. as pet rats grew in popularity.
  43. 250-year-old guidebooks detail tips on rodent domestication,
  44. and how to breed the most affectionate rats in various coat colors and patterns.
  45. Wild brown rats finally entered Europe
  46. sometime between the 13th and 18th century,
  47. by ship and perhaps, sometimes, by treading water.
  48. Some say a particularly violent earthquake in 1727
  49. led hordes of brown rats to swim across the Volga River into Russia.
  50. Eventually, the larger and more adaptable brown rats displaced the black rats
  51. in homes and cities across Europe and North America
  52. by outcompeting them for resources.
  53. The Industrial Revolution only bolstered the lives of industrious brown rats.
  54. As cities expanded, rats thrived by making homes of our sewers
  55. and buffets of our trash.
  56. They even evolved resistance to our poisons,
  57. to the dismay of exterminators who inherited Jack Black's mission.
  58. But the human-rat race took a monumental turn in 1906,
  59. when the Wistar Institute in Philadelphia bred the first standard rat strain for scientific research.
  60. Rats are unrivaled lab animals.
  61. Their bodies function and respond to disease similarly to humans,
  62. and we share much of the same genome.
  63. Plus, they're smart,
  64. which has made them indispensable to neuroscience and psychology research.
  65. In the 1960s, for example,
  66. scientists observed that rats raised with toys and companions
  67. had thicker cortical brain tissue than those who didn't.
  68. This helped establish the concept of neuroplasticity,
  69. which explains how our environments and learning shape our minds.
  70. Today, rats are often regarded as the most successful invasive species in the world.
  71. And this comes at a price,
  72. they often live at the mercy of human priorities.
  73. In cities like New York,
  74. they're reviled enough to warrant multi-million-dollar extermination efforts.
  75. But if history is any indication,
  76. no amount of money, nor skill of rat catcher,
  77. will ever fully rid us of our rodent shadows.