2022-03-24 ブラウン大学
A boa constrictor feeds on a lizard in Tijuca Forest National Park, Rio de Janeiro, Brazil.Vitor Marigo / Aurora Photos/Getty Images/Aurora Open
・ヘビの頭に最も近い鱗状のコイルが獲物を絞り出すのに大忙しのとき、爬虫類は呼吸方法を変えるだけで、肋骨と体長より下の筋肉を使うことができる。
・この研究は、血圧計を膨らませてボアコンストリクターの体のさまざまな部分を固定し、同時にX線スキャンで肋骨の動きをモニターしたものである。その結果、ヘビは肋骨の異なるセットを使って、蛇腹のように空気を吸い込むように簡単に変化することがわかった。
<関連情報>
- https://www.npr.org/2022/03/24/1088192843/this-trick-keeps-snakes-from-suffocating-as-they-squeeze-and-swallow-their-prey
- https://journals.biologists.com/jeb/article-abstract/225/6/jeb243119/274764/Modular-lung-ventilation-in-Boa-constrictor?redirectedFrom=fulltext
ボアコンストリクターのモジュール式肺換気法 Modular lung ventilation in Boa constrictor
John G. Capano,Scott M. Boback,Hannah I. Weller,Robert L. Cieri,Charles F. Zwemer,Elizabeth L. Brainerd
Journal of Experimental Biology Published:24 MARCH 2022
https://doi.org/10.1242/jeb.243119
ABSTRACT
The evolution of constriction and of large prey ingestion within snakes are key innovations that may explain the remarkable diversity, distribution and ecological scope of this clade, relative to other elongate vertebrates. However, these behaviors may have simultaneously hindered lung ventilation such that early snakes may have had to circumvent these mechanical constraints before those behaviors could evolve. Here, we demonstrate that Boa constrictor can modulate which specific segments of ribs are used to ventilate the lung in response to physically hindered body wall motions. We show that the modular actuation of specific segments of ribs likely results from active recruitment or quiescence of derived accessory musculature. We hypothesize that constriction and large prey ingestion were unlikely to have evolved without modular lung ventilation because of their interference with lung ventilation, high metabolic demands and reliance on sustained lung convection. This study provides a new perspective on snake evolution and suggests that modular lung ventilation evolved during or prior to constriction and large prey ingestion, facilitating snakes’ remarkable radiation relative to other elongate vertebrates.
