Propelling and perturbing appendages together facilitate strenuous ground self-righting

  1. Ratan Othayoth
  2. Chen Li  Is a corresponding author
  1. Johns Hopkins University, United States


Terrestrial animals must self-right when overturned on the ground, but this locomotor task is strenuous. To do so, the discoid cockroach often pushes its wings against the ground to begin a somersault which rarely succeeds. As it repeatedly attempts this, the animal probabilistically rolls to the side to self-right. During winged self-righting, the animal flails its legs vigorously. Here, we studied whether wing opening and leg flailing together facilitate strenuous ground self-righting. Adding mass to increase hind leg flailing kinetic energy increased the animal’s self-righting probability. We then developed a robot with similar strenuous self-righting behavior and used it as a physical model for systematic experiments. The robot’s self-righting probability increased with wing opening and leg flailing amplitudes. A potential energy landscape model revealed that, although wing opening did not generate sufficient kinetic energy to overcome the high pitch potential energy barrier to somersault, it reduced the barrier for rolling, facilitating the small kinetic energy from leg flailing to probabilistically overcome it to self-right. The model also revealed that the stereotyped body motion during self-righting emerged from physical interaction of the body and appendages with the ground. Our work demonstrated the usefulness of potential energy landscape for modeling self-righting transitions.

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Author details

  1. Ratan Othayoth

    Department of Mechanical Engineering, Johns Hopkins University, Baltimore, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5431-9007
  2. Chen Li

    Department of Mechanical Engineering, Johns Hopkins University, Baltimore, United States
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7516-3646


Army Research Office (W911NF-17-1-0346)

  • Chen Li

Burroughs Wellcome Fund (1014584.01)

  • Chen Li

Johns Hopkins University

  • Chen Li

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Gordon J Berman, Emory University, United States

Version history

  1. Received: June 20, 2020
  2. Accepted: June 15, 2021
  3. Accepted Manuscript published: July 7, 2021 (version 1)
  4. Version of Record published: July 27, 2021 (version 2)


© 2021, Othayoth & Li

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.


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  1. Ratan Othayoth
  2. Chen Li
Propelling and perturbing appendages together facilitate strenuous ground self-righting
eLife 10:e60233.

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