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Proceedings of the National Academy of Sciences of the United States of America2016; 113(25); 6979-6984; doi: 10.1073/pnas.1604009113

Leaping eels electrify threats, supporting Humboldt’s account of a battle with horses.

Abstract: In March 1800, Alexander von Humboldt observed the extraordinary spectacle of native fisherman collecting electric eels (Electrophorus electricus) by "fishing with horses" [von Humboldt A (1807) Ann Phys 25:34-43]. The strategy was to herd horses into a pool containing electric eels, provoking the eels to attack by pressing themselves against the horses while discharging. Once the eels were exhausted, they could be safely collected. This legendary tale of South American adventures helped propel Humboldt to fame and has been recounted and illustrated in many publications, but subsequent investigators have been skeptical, and no similar eel behavior has been reported in more than 200 years. Here I report a defensive eel behavior that supports Humboldt's account. The behavior consists of an approach and leap out of the water during which the eel presses its chin against a threatening conductor while discharging high-voltage volleys. The effect is to short-circuit the electric organ through the threat, with increasing power diverted to the threat as the eel attains greater height during the leap. Measurement of voltages and current during the behavior, and assessment of the equivalent circuit, reveal the effectiveness of the behavior and the basis for its natural selection.
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Publication Date: 2016-06-06 PubMed ID: 27274074PubMed Central: PMC4922196DOI: 10.1073/pnas.1604009113Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • U.S. Gov't
  • Non-P.H.S.

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article provides validating evidence for the centuries-old anecdote of ‘fishing with horses’ by observing that electric eels can leap from water to attack threat, discharging high-voltage volleys to short-circuit their electric organ through the threat.

Origin of the Study

  • The inspiration for this research came from an account given by Alexander von Humboldt in 1800, in which he described a technique used by native South Americans to catch electric eels.
  • The method involved driving horses into a pool where electric eels were present, prompting the eels to surface and attack the horses by pressing their bodies against them and discharging electricity until exhausted.
  • After the eels were drained of energy, they could be safely collected. Despite the popularity of this account, there has been no scientific observation supporting this behavior until now.

New Observations

  • The researcher observed similar behavior exhibited by electric eels that corroborate Humboldt’s account.
  • The defensive approach of the eel includes coming out of the water and pressing its chin against a threatening object, typically a metallic conductor, discharging high-voltage electricity.
  • This electricity released is transferred to the threat, increasing in power as the eel gets higher from the water surface while leaping.

Implications of the Research

  • By measuring the voltages and currents during these interactions, the researcher determined the behavior’s effectiveness and implied natural selection choices.
  • The findings confirm that this behavior has evolved to protect against potential threats, making it a survival tactic.
  • The study provides a unique understanding of the electric eel’s behavior, extending the ability to harness the potential of these creatures and their unique electric organ in the field of bio-engineering or electrical mechanics.

Cite This Article

APA
Catania KC. (2016). Leaping eels electrify threats, supporting Humboldt’s account of a battle with horses. Proc Natl Acad Sci U S A, 113(25), 6979-6984. https://doi.org/10.1073/pnas.1604009113

Publication

Proceedings of the National Academy of Sciences of the United States of America
ISSN: 1091-6490
NlmUniqueID: 7505876
Country: United States
Language: English
Volume: 113
Issue: 25
Pages: 6979-6984

Researcher Affiliations

Catania, Kenneth C
  • Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235 ken.catania@vanderbilt.edu.

MeSH Terms

  • Animals
  • Behavior, Animal
  • Electrophorus
  • Horses
  • South America

Conflict of Interest Statement

The author declares no conflict of interest.

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Citations

This article has been cited 7 times.
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