The Nishikawa Lab
Photo and Video Gallery
The biomechanics of rapid movements
Toads and chameleons make their living by shooting their tongues out of their mouths at incredible speeds in order to catch their food. How do they do it? And can we, by studying the underlying mechanical principles, explain these complex behaviors and perhaps even develop useful technologies to benefit mankind?
Neuromechanics of prey capture in frogs
This is a high-speed movie of a toad (Bufo woodhousii) ballistically projecting its tongue to capture a cricket. The movie plays at about 1/30 real time. The tongue lengthens over 200% of resting length. This movement is powered by extremely rapid mouth opening transferring momentum to the tongue. The tongue contains intrinsic muscles, but none of them can account for the velocities and accelerations observed during ballistic tongue projection.
This is a high-speed movie of an Indonesian tree frog (Litoria caerulea) projecting its tongue to capture a cricket. The movie plays at about 1/30 real time. Tongue protraction by this animal is much slower than that of those species that ballistically project their tongue, such as toads, and the tongue does not lengthen past resting length when protracted.
A high-speed movie of an African pig-nosed frog (Hemisus marmoratum) protracting its tongue to capture a termite.Tongue protraction is accomplished by a muscular hydrostatic mechanism allowing the animals to aim the tongue during protraction. (Hemisus marmoratum) is unusual in that it has two muscular "pinchers" at the tongue tip which allows it to grab prey. The movie plays at about 1/10 real time.
Ecomorphology of lizard feeding
This is a male Crotaphytus collaris from northwestern Arizona in its natural habitat (30K).
This is a male Crotaphytus collaris from northwestern Arizona in hand (30K).
This is a closeup of a gorgeous eye of male Crotaphytus collaris (22k).
This is a juvenile male Crotaphytus collaris from northwestern Arizona. Note the orange coloration, similar to that in breeding females, which will fade and disappear in the first year of life (28K).
This is another view of a juvenile male Crotaphytus collaris. A few of the teeth are visible (22k).
This is a Gambelia copei caught with Eric Zepenewski and Carrie Carreno in Baja California Sur. This specimen constitutes a significant range extension for the species (20k).
Another view of the Gambelia copei caught with Eric Zepenewski and Carrie Carreno in Baja California Sur (20k).
As part of Kris's dissertation research, bite force in several species of crotaphytid lizards were measured to relate their feeding biology to the structure and function of the feeding apparatus. This is a male Crotaphytus collaris from northern Arizona biting on a double-cantilever bite-force transducer (28k).
These are side views of the skulls of two species of crotaphytid lizards, Crotaphytus collaris and Gambelia wislizenii. Note the differences in cranial robustness, snout length, and tooth form. Crotaphytus collaris includes many hard-integumented beetles in its diet, while Gambelia wislizenii is a big consumer of other species of lizards. The osteological and dental differences between these species reflect the differences in dietary ecology (24k).
Working with large crocodilians is necessarily a cooperative effort. Here, at the Saint Augustine Alligator Farm in Florida, a large gator is taken to a scale for weighing.
Here, a moderately large alligator is being weighed.
Pair of adult southern plateau lizards (Sceloporus undulatus tristichus) found together under a coverboard in the thin treatment; female on top; male on bottom; adult females are generally larger than adults males.