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Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact
Birds land on a wide range of complex surfaces, yet it is unclear how they grasp a perch reliably. Here, we show how Pacific parrotlets exhibit stereotyped leg and wing dynamics regardless of perch diameter and texture, but foot, toe, and claw kinematics become surface-specific upon touchdown. A new...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
eLife Sciences Publications, Ltd
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684272/ https://www.ncbi.nlm.nih.gov/pubmed/31385573 http://dx.doi.org/10.7554/eLife.46415 |
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author | Roderick, William RT Chin, Diana D Cutkosky, Mark R Lentink, David |
author_facet | Roderick, William RT Chin, Diana D Cutkosky, Mark R Lentink, David |
author_sort | Roderick, William RT |
collection | PubMed |
description | Birds land on a wide range of complex surfaces, yet it is unclear how they grasp a perch reliably. Here, we show how Pacific parrotlets exhibit stereotyped leg and wing dynamics regardless of perch diameter and texture, but foot, toe, and claw kinematics become surface-specific upon touchdown. A new dynamic grasping model, which integrates our detailed measurements, reveals how birds stabilize their grasp. They combine predictable toe pad friction with probabilistic friction from their claws, which they drag to find surface asperities—dragging further when they can squeeze less. Remarkably, parrotlet claws can undergo superfast movements, within 1–2 ms, on moderately slippery surfaces to find more secure asperities when necessary. With this strategy, they first ramp up safety margins by squeezing before relaxing their grasp. The model further shows it is advantageous to be small for stable perching when high friction relative to normal force is required because claws can find more usable surface, but this trend reverses when required friction shrinks. This explains how many animals and robots may grasp complex surfaces reliably. |
format | Online Article Text |
id | pubmed-6684272 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | eLife Sciences Publications, Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-66842722019-08-09 Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact Roderick, William RT Chin, Diana D Cutkosky, Mark R Lentink, David eLife Evolutionary Biology Birds land on a wide range of complex surfaces, yet it is unclear how they grasp a perch reliably. Here, we show how Pacific parrotlets exhibit stereotyped leg and wing dynamics regardless of perch diameter and texture, but foot, toe, and claw kinematics become surface-specific upon touchdown. A new dynamic grasping model, which integrates our detailed measurements, reveals how birds stabilize their grasp. They combine predictable toe pad friction with probabilistic friction from their claws, which they drag to find surface asperities—dragging further when they can squeeze less. Remarkably, parrotlet claws can undergo superfast movements, within 1–2 ms, on moderately slippery surfaces to find more secure asperities when necessary. With this strategy, they first ramp up safety margins by squeezing before relaxing their grasp. The model further shows it is advantageous to be small for stable perching when high friction relative to normal force is required because claws can find more usable surface, but this trend reverses when required friction shrinks. This explains how many animals and robots may grasp complex surfaces reliably. eLife Sciences Publications, Ltd 2019-08-06 /pmc/articles/PMC6684272/ /pubmed/31385573 http://dx.doi.org/10.7554/eLife.46415 Text en © 2019, Roderick et al http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited. |
spellingShingle | Evolutionary Biology Roderick, William RT Chin, Diana D Cutkosky, Mark R Lentink, David Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact |
title | Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact |
title_full | Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact |
title_fullStr | Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact |
title_full_unstemmed | Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact |
title_short | Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact |
title_sort | birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact |
topic | Evolutionary Biology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684272/ https://www.ncbi.nlm.nih.gov/pubmed/31385573 http://dx.doi.org/10.7554/eLife.46415 |
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