QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online August 17, 2006
Journal of Experimental Biology 209, 3358-3369 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02381

This Article Summary Full Text Full Text (PDF) Supplementary Material Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Socha, J. J. Search for Related Content PubMed PubMed Citation Articles by Socha, J. J.

Becoming airborne without legs: the kinematics of take-off in a flying snake, Chrysopelea paradisi

John J. Socha

Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA

View larger version (17K): [in a new window]   Fig. 1. Representative anchored J-loop take-off sequence in C. paradisi. Overhead (A), side (B) and front (C) views, traced from video records. Sequence starts just prior to the first upward movement. The preparation phase, in which the snake drops down from the branch, is not shown. In side view, arrows refer to horizontal and vertical axes. Scale bar, 25 cm. Mass=83 g, SVL=83 cm.

View larger version (25K): [in a new window]   Fig. 2. Representative traces of other modes of take-off in C. paradisi. Side (left) and overhead (right) views of sliding J-loop, side-loop and dive take-offs. In side view, arrows refer to horizontal and vertical axes. Scale bar, 25 cm. (A) Sliding J-loop take-off sequence. Mass=26 g, SVL=62 cm. (B) Side-loop take-off sequence. Mass=16 g, SVL=54 cm. (C) Dive take-off sequence. Mass=11 g, SVL=47 cm.

View larger version (12K): [in a new window]   Fig. 3. Types of branch `grips'. Overhead view of the snake on the branch, with the anterior body of the snake hanging off the right side and below the branch (into the page). The location of the snake's vent is represented by a yellow dot. (A) Most common grip configuration. Grips generally comprised at least one loop with two points of orthogonal contact (gray arrows). (B) Grip with the first loop hanging from the branch, with the middle of the loop (gray arrow) not contacting the branch. (C) Grip with posterior body and tail wrapping under the branch in a spiral (gray arrow), used less frequently than A or B. In some trials, the snake threw multiple wraps around the branch in a more circular fashion.

View larger version (16K): [in a new window]   Fig. 4. Three-dimensional positions of the head, midpoint, and vent in representative anchored and sliding J-loop take-offs. Head, midpoint and vent points are represented with triangles, circles and squares, respectively. Scale bar, 25 cm. Side (A), overhead (B) and rear (C) views of unsmoothed data sampled at 60 Hz. In both take-offs, the head traces approximately the same path, moving upward, outward, and then down. In the anchored J-loop take-off, the snake's head has a slight rearward component during the first upward movement. The upward movement during the initial acceleration has almost no lateral component. Note the relative lack of movement of the vent (gray arrow, A) early in the anchored J-loop take-off. Anchored J-loop take-off: mass=27 g, SVL=63 cm; sliding J-loop take-off: mass=26 g, SVL=62 cm.

View larger version (35K): [in a new window]   Fig. 5. Representative traces of position, velocity and acceleration in looped take-off modes. Data are from 3D coordinates of the head. The lateral, horizontal and vertical components are represented by a thin blue line, thick red line and thick green line, respectively. Gray banding represents the vertical (light gray) and horizontal (dark gray) acceleration phases. (A-C) Anchored J-loop take-off. (D-F) Sliding J-loop take-off.

View larger version (12K): [in a new window]   Fig. 6. Head angle changes in an anchored J-loop take-off. Head angle is the angle between the head axis and the horizon in lateral view. Intervals are 125 ms. (A) Head angle vs position. Head angles are represented by the angle of the black bars drawn at successive head positions, labeled `1' through `8'. Position 1 represents the snake just prior to the first upward movement. (B) Head angle vs time. The head angle starts at 18° and begins to increase at about position 4, when the snake reaches the apex of the jump. At position 8, the head angle is 40°, aligned approximately 10-20° above the trajectory path in the post-take-off ballistic dive. Mass=53 g, SVL=75 cm.

View larger version (43K): [in a new window]   Fig. 7. Summary of performance comparisons. (A-D) Differences in looped take-offs (blue; N=15) vs non-looped take-offs (gray; N=9). (E-G) Differences in anchored J-loop take-offs (red; N=11) vs sliding J-loop take-offs (yellow; N=4). All comparisons are statistically significant except where noted by `NS'.