Vol. 5, pp. 112-116

Asiatic

Herpetological Research

December 1993

Resting Metabolic Rate in Three Age-groups of Alligator sinensis

Pei-chao Wang and Jiang-hua Zhang
Department of Biology, East China Normal University, Shanghai 200062, People's Republic of China

Abstract. -The resting metabolic rate in three age-groups of Alligator sinensis is influenced thetemperature, season, body weight and other factors. Among these factors, the effect of body weight,temperature, season, which are greater than that of others. The relationship between the body weight andthe resting metabolism is not consistent with the "third-quarter" surface area law. In the equation M=aW^,
the value of "a" ranges from 0.009 to 0.028, and the value of "b" ranges from 0.522 to 0.591, so that b isapproximately equal to 2/3 in empirical equation.

Key Words:

Reptilia, Crocodilia, Alligatoridae, Alligator sinensis, China, metabolism.

Introduction
Alligator sinensis is a kind of special andprecious reptile. It is classed as a first

grade protected form of wildlife in China.
Much research on the adaptability ofAlligator sinensis have been done in thefields of morphology, distribution,reproduction and so on (Chen, 1985; Chenand Wang, 1984). Zhang (1986; 1989)
reported information about infant Alligatorsinensis whose weights ranged from 35 to50 grams. Because energy metabolism is avery important criterion for the adaptabilityof Alligator sinensis, the purpose of ourwork was to explore the regularity of daily
gain in total energy from diet, with relation
to digestibility and energy allocation and toexplore the resting metabolic rate ofAlligator sinensis. This paper deals withthe resting metabolic rate of three agegroups in Alligator sinensis.

Materials and Methods

The Alligator sinensis that we used wereprovided by the Shanghai Zoo. The total
number of tested animals was 13. Five ofthem were bom in 1980, and their average
body weight was 2.84 ± 0.053 (M±SD) kg
1986
and 3.126±0.053 kg at the end of 1987.
Four of them were born in 1981, and theirat the beginning of the experiment inaverage body weight was 1.5410.59 kg at
the beginning of the experiment in 1986
and 2.13910.857 kg at the end of theexperiment in 1987. Four of them wereborn 1982, and their average body weightDecember 1993

Table 1.

Months

Asiatic Herpetological ResearchVol. 5 p. 113

The linear regression equations and the approximate surface area equations of Alligator sinensis.

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14

Asiatic Herpetological Research

December 1993

Vol. 5 p. 115

the highest level; in September, the30

RMR

becomes lower and it is continues to fall inThis suggests that the energy
consumption is relevant to the seasonalchange which also corresponds with therules of the energy consumption andOctober.

25

requirements of Alligator sinensis. Amongthe growth months of Alligator sinensis asin July, there is a high water temperature,and there is intensive metabolism and rapid
growth in Alligator sinensis. The data
below support this statement. The groupborn in 1980 ingested daily 172.02±77.65(M±SD) g fresh fish in June,
221.35±35.58 g fresh fish in July,

4=s

15

7Months

FIG.

2.

Seasonal influence on theAlligator sinensis maintained at 25°C.

RMR ofSolid circle-1980 age group; x- 1981 age group; open circle1982 age group.
Effects of temperature and season

Table 3 shows that the resting metabolic
rate of Alligator sinensis affected by thetemperature and season. In the cool season
or under the low temperature, the resting
metabolic rate is at a lower level, and viceversa. This is similar to that of the otherreptiles (Coulson and Coulson, 1986;
Huggins et al., 1971; Wang and Lu, 1986;
Wang and Xu, 1987; Wang et al., 1983,1988). This metabolic character is due tothe result of acclimatization of seasonaltemperature rhythm in evolution of animals.

We further analyze the relationshipbetween RMR (resting metabolic rate) andtemperature as well as season. We used
0.56 power of body weight to adjust allvalues of observing, so that the effect ofbody weight in RMR is eliminated. Theresults are summarized in Table 3. The
values of ml O 2 /W 56 hr from Table 3-1

show the temperature and season effect onRMR. The levels of RMR are higher underhigh temperatures than low, and it is asimilar state that there is a higher level ofduring hot seasons than during cool54.73±41.14 g fresh fish in September.
The daily body weight growth of the group
was also rapid, such as 10.3 g in June,
44.6 g in July and 15.8 g in September. InMay, Alligator sinensis had just awaked
wasfrom hibernation, when thelower. In October, Alligator sinensis will
declined tostop the feeding when thea low level, and there were some changes

RMR

RMR

in

their physiological attributes for thecoming hibernation stage.

It isindicated

Alligator sinensis has a series ofadaptive strategies for the seasonalchanges.
thatTlie relationship between age andRMR

The relationships between age and RMRshown in Table 3.
There are two kinds of data on the RMR.
The first RMR in Table 3 is influenced bybody weight, and does not eliminate theeffect of body weight. It is expressed in ml
The second RMR eliminates
02/kg hrthe effect of body weight by expressing
RMR in ml O 2 /W 056 hr A comparisonin three age groups are11.

1.

RMR
RMR

in threeon the level of both kinds ofinon
100of ageisbasedage groupsofin1980.
Theresultscomparisongroupsfalls assuggest that the first kind of
the age of groups increases. The second
kind ofslightly falls in younger
ina few months.
groups, except

RMR

RMR

RMR

Acknowledgments

seasons.

From Fig. 2, is is further shown that theRMR changes with seasons under the same
temperature of 25°C. In July, the RMR iswas supported by theFund of the State Educational
Committee, China, East China NormalThis

study

ScientificDecember 1993

Asiatic Herpetological ResearchVol. 5 p. 116

University and Shanghai Zoo. We thankProfessor Ruyong Sun, Prof. Wenji
Huang, Prof. Ermi Zhao for helpful

Wediscusssions and encouragement.
TedDr.
Joanen,tothanklikewould also
Dr. E. Norber Smith, and Dr. Shoji

Tokunaga for providing some literature.

of small caimans

under basal conditions.

Physiological Zoology 44:40-47.

WANG, P. C, S. ZHAO, H. J. LU, L. B. ZHU,AND Z. X. CHI. 1980. A simple closed-system
for measuring the oxygen
consumption of the terrestrial vertebrate.
Journal of East China Normal University

respirometer(Natural Science) 2:126-131. (In Chinese, with

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