In 1848, London natural history dealer Samuel Stevens established a collecting agency that supported field collectors, including Bates and Wallace. This arrangement helped finance their work by advancing funds and selling part of the specimens they shipped home.
In the late 1840s, Henry Walter Bates and Alfred Russel Wallace decided to travel to the Amazon Basin to collect animals and plants for study and for sale to European collectors and museums. This plan helped them fund long-term fieldwork at a time when most naturalists did not have independent wealth.
Bates and Wallace left England by ship from Liverpool in April 1848, beginning their Amazon expedition. Their goal was to collect widely across the region and send specimens back to London through an agent who could sell duplicates and place key specimens in collections.
They reached Pará (now Belém) at the mouth of the Amazon near the end of May 1848. From this base, they began learning local conditions and making short collecting trips into nearby forests before pushing farther upriver.
Working alone, Bates traveled up the Amazon system and used a series of base camps to collect across different environments. This long, place-based fieldwork let him compare related species across regions and seasons, a key step toward later ideas about mimicry and adaptation.
After roughly a year of joint collecting around Pará and nearby river routes, Bates and Wallace separated to work independently. Dividing the region let them cover more habitats and collect more species, which was essential for both science and income from specimen sales.
Bates regularly sent specimens to England during the expedition and took steps to reduce the risk of total loss during shipping. Later accounts note he used multiple shipments, a strategy shaped by the dangers of long sea travel and by Wallace’s earlier shipping disaster.
In 1852, Alfred Russel Wallace attempted to return to England, but a shipboard disaster led to the loss of most of his Amazon specimens and notes. This event became a cautionary example for other collectors and is often contrasted with Bates’s more successful preservation of his own collections.
Bates ended his field expedition and returned to Britain in 1859 after nearly eleven years in the Amazon Basin. He brought back a very large natural history collection, including thousands of insect species that were new to science, which gave him a strong evidence base for later publications.
Bates published a detailed scientific study of Amazon butterflies in the Transactions of the Linnean Society, describing how some harmless species closely resemble toxic or otherwise protected species. He argued that this resemblance can help the mimic avoid predators—an idea that later became known as Batesian mimicry.
In 1863, Bates published The Naturalist on the River Amazons, a two-volume account combining travel narrative with natural history observations from his expedition. The book made his Amazon work widely accessible and helped spread attention to tropical biodiversity and evolutionary explanations for it.
After his Amazon work was published and his reputation grew, Bates took on a senior administrative post at the Royal Geographical Society as assistant secretary in the mid-1860s. This position helped him shape how new exploration results were edited, presented, and circulated, extending his influence beyond the Amazon expedition itself.
Henry Walter Bates' Amazon Expedition and Mimicry Research (1848–1859)