plate measures, provided estimates of the joint moments, whichwere converted to force using measures of the muscles' momentarms over the range of joint angles used during stance. We wereable to separate two muscle groups with differing economies offorce production and examine the effects of speed on the cost ofproducing force.

doi:10.1016/j.cbpa.2008.04.093

A2.24Built for speed? Anatomy of the cheetah (Acinonyx jubatus) andthe greyhound (Canis familiaris)

P. Hudson (Royal Veterinary College); S. Clancy (Royal VeterinaryCollege); E. Lane (National Zoological Garden of South Africa); S. Corr(Royal Veterinary College); A. Wilson (Royal Veterinary College);R. Payne (Royal Veterinary College)

The cheetah is the fastest living terrestrial mammal, anddemonstrates some unusual morphology compared to other felids. Itis of similar size and build to the racing greyhound, however, whilstthe cheetah is able to attain speeds of 29 ms−1 the greyhound can onlyachieve 18 ms−1. Here, as the first part of a research program oncheetah locomotion we examined the musculoskeletal system of thecheetah and greyhound. We hypothesised that similar anatomicaladaptations for speed will be found in both species and that thecheetah will demonstrate a greater extent of specialisation. Specifi-cally we predicted that cheetahs should have smaller hip musclemoment arms to allow for an increased hip rotational velocity,decreased distal segment masses and an increased amount of spinalmusculature.

In this study the muscle architecture of the forelimbs andhindlimbs of three cheetahs were described and quantified. Themoment arms of the major limb muscles were also measured usingthe tendon travel method. These data were then compared to existinggreyhound data to identify anatomical adaptations to explain howcheetahs are able to attain superior speeds.

doi:10.1016/j.cbpa.2008.04.094

A2.25Locomotor plasticity of larval zebrafish in high viscosityenvironments

N. Danos (Harvard University)

Routine turns are a normal part of the zebrafish foraging locomotorbehavior that provides a good context in which to study thedevelopmental plasticity of locomotor behavior. Zebrafish are raisedfrom 1 to 5 days post fertilization in increased viscosity water. Threeviscosity treatments are applied to different groups of larval zebrafish,the highest viscosity treatment being 15 times as viscous as normalwater. At the endof this period 3 to 5 fish fromeach treatment are filmedperforming routine turns in their growth medium (native medium).They are then transferred into water of normal viscosity and filmedwithin the first 30 min of being in normal water. Fish remain in normalwater for 24 h and are then filmed again in normal water. Controls arealso performedwhere zebrafish raised inwater are transferred to higherviscositywaterand filmedafter30minand24h. I hypothesize that if fish

aim for an optimum in foraging, i.e. maximum area searched asmeasured by the product of turn frequency and body curvature, turningkinematics of fish in their native viscosities should be indistinguishable.However, if the behavior is determined by mechanosensory input or bymorphological changes resulting from the treatment, the kinematics offish in the various treatments will differ. In order to differentiatemorphological changes from behavioral ones I quantify the turningkinematics of the fish after the longer acclimation period. If the changesare completely plastic, after 24 h in normal water the fish's behaviorshould be indistinguishable from that of fish raised in normal water. If,however, the mechanosensory input led to irreversible neurological ormorphological changes, fish raised in higher viscosities should performroutine turns with increased angular velocity in water.

doi:10.1016/j.cbpa.2008.04.095

A2.26The effects of wing loading on take-off performance ingreenfinches and yellowhammers

M. Kauffmann (University of Leeds)

Body mass and take-off performance are important factors in thesurvival of an individual bird. A high body mass is likely to be selectedfor, since storing fat reduces the risk of starvation. Another factor underselection is take-off performance, since it is a prime determinant of anindividual’s ability to escapepredators. However, take-off performanceis likely to be impaired by increased body mass. Therefore a trade-offexists between maximizing escape performance and minimizing therisk of starvation. We tested the hypothesis that take-off performancedecreases with increasing wing loading (body mass/wing area).

We used high-speed video recordings and a kinematic analysis toquantify the take-off performance of greenfinches (Carduelis chloris)and yellowhammers (Emberiza citrinella). The power required toincrease the animal's kinetic and potential energy, which encom-passes changes in take-off angle, velocity and acceleration, wascalculated as a measure of take-off performance. A full aerodynamicanalysis was also performed to calculate the total mechanical powerrequirements in relation to body and flight muscle mass.

Contrary to our predictions, we found that mass-specific aero-dynamic power during take-off was not affected by wing loading ineither species. However we found a significant increase in the meanrate of kinetic energy with increasing body mass in yellowhammers,counterbalanced by a tendency for a decrease in the mean rate ofpotential energy. The same tendency was found in greenfinches,which may suggest that heavier birds use another strategy, increasingforward velocity at the expense of altitude gain.

doi:10.1016/j.cbpa.2008.04.096

A2.27A comparative analysis of the normal swimming performance oftwo subcarangiforms, blind Mexican cave fish (Astyanax fasciatus)and goldfish (Carassius auratus)

R. Holbrook, R. Bomphrey, S. Walker, G. Taylor, A. Thomas, T. Burt dePerera (University of Oxford)

Here we compare the normal swimming performance of twosubcarangiform fish, the blind Mexican cave fish (Astyanax fasciatus) and

S70 Abstracts / Comparative Biochemistry and Physiology, Part A 150 (2008) S64–S73