Aerial locomotion is conveniently treated under parachuting, gliding, and flying, al? though these categories intergrade freely. Soaring might be treated separately, but is legitimately regarded as gliding with the downward gradient balanced by thermal or mechanical updrafts. In the flying fishes (Exocoetus) we find what Gray (1953) calls velocity gliding; they depend on the kinetic energy of their moving bodies. Glides of 50 yards are not uncommon and this distance may be greatly exceeded in turbulent conditions. It has been estimated that such glides require a take-off speed of 30-35 mph, a speed unbelievably high for normal swimming. However, photographs show that, after the body breaks out of the water, the tail continues to drive the fish forward. Thus we have an analogy to a hydroplane rising on to the step.
[1]
A. Raspet,et al.
Biophysics of Bird Flight.
,
1960,
Science.
[2]
O. B. O. Savile,et al.
ADAPTIVE EVOLUTION IN THE AVIAN WING
,
1957
.
[3]
T. H. Hamilton.
THE ADAPTIVE SIGNIFICANCES OF INTRASPECIFIC TRENDS OF VARIATION IN WING LENGTH AND BODY SIZE AMONG BIRD SPECIES
,
1961
.
[4]
James A. Oliver,et al.
"Gliding" in Amphibians and Reptiles, with a Remark on an Arboreal Adaptation in the Lizard, Anolis carolinensis carolinensis Voigt
,
1951,
The American Naturalist.
[5]
John H. Ostrom,et al.
The Origin of Birds
,
1926
.