The following is a grant proposal I wrote to conduct my Ph.D. work on the thermal biology of rubber boas in Idaho. The proposal was written to the American Museum of Natural History. You should view this proposal as a sample of what should be included in terms of content of your proposal. However, this proposal should not be used as an example of the formatting of your proposal. You should follow the instructions I gave to format your proposal correctly.

Testing and Applying the Coadaptation Hypothesis:

the Thermoregulatory Behavior and Thermal Physiology of

the Rubber Boa, a Cold Tolerant Snake

Coadaptation, the beneficial interaction of complementary traits, is an important concept of evolutionary thought (Huey and Bennett, 1987). By studying the coadaptation of thermal physiology and thermoregulatory behavior of snakes, I can test how this concept applies to thermal biology. Many snake species constitute good systems for studies of thermal biology because their activity and body temperatures can be monitored in the field using radiotelemetry, models can be constructed which accurately measure the range of possible body temperatures of snakes (Peterson, 1987), and physiological studies of snakes can readily be performed in the laboratory (Stevenson et al., 1985). Many snakes appear to thermoregulate behaviorally to optimize physiological processes such as digestion and crawling speed. Diurnal snakes are active in environments that offer a wide range of temperatures in which to thermoregulate. Diurnal snakes generally show a good correlation among the temperatures at which they are active (activity temperatures), the temperatures they prefer in a laboratory thermal gradient (thermal preference), and the temperature at which they perform optimally (optimal performance temperature) (Lillywhite, 1987; Peterson, 1987). Nocturnal snakes are active in an environment which is often cooler and offers a narrow range of temperatures in which to thermoregulate. Consequently, nocturnal snakes often exhibit lower activity temperatures than diurnal species. Based on the coadaptation hypothesis, I predict that snakes with lower activity temperatures will have a corresponding reduction in thermal preference and optimal performance temperature. Furthermore, I predict that the thermal performance breadth, the range of temperatures at which snakes perform well, of nocturnal snakes will be wider.

The rubber boa (Charina bottae) is primarily nocturnal and displays lower activity temperatures than sympatric diurnal species (Ross, 1931; Wright and Wright, 1957; Cunningham, 1966). My preliminary field telemetry data indicate rubber boas are active at temperatures at least as low as 12.5oC. My general objective is to examine the extent of coadaptation between the thermoregulatory behavior and the thermal physiology in nocturnal snakes using the rubber boa as a test species. My specific objectives include:

1. Determine when and at what environmental and body temperatures rubber boas are active.

2. Establish the thermal preference of rubber boas.

3. Examine how body temperature variation affects performance.

4. Analyze the relationships among activity temperature, thermal performance, and preference.


I will determine when and at what body temperatures rubber boas are active in the field using surgically implanted temperature and motion sensitive radiotransmitters. These snakes will be continuously monitored with an automated field telemetry system. The body temperatures of three rubber boas are currently being monitored in the field using this method. I am using a Telonics Fast Data system to record snake body temperatures and activity at five minute intervals. A Campbell Scientific datalogger is being used to continuously monitor air, soil, and snake model temperatures. The study site is a box canyon located approximately 10 km east of Pocatello, Idaho at an elevation of 1700 m. Vegetation is predominately maple and douglas fir interspersed with dry sagebrush/grassy areas. There are many large, south facing, rock outcroppings in which the snakes hibernate.

In the laboratory, I will determine the thermal preference of rubber boas in an artificial thermal gradient. My preliminary data indicate a thermal preference several degrees lower than that of diurnal species such as garter snakes (Thamnophis sp.). I will also test the thermal dependency of digestion, crawling speed, tongue flick rate, strike speed and metabolism. Activity periods and thermal preference will be measured using a computerized laboratory telemetry system. This system will continuously monitor up to 20 snakes and will allow control of temperature and photoperiod.

Data will be used to ascertain the relationships among thermal preference, optimal performance temperature, thermal performance breadth, and activity temperature. Correlation of different types of performance (i.e. crawling speed and digestion) with thermal preference and activity temperatures may be complicated. For example, the optimal temperature for digestion may coincide well with thermal preference, indicating good coadaptation for digestion. However, the optimal temperature for crawling speed may be higher than observed activity temperatures, indicating poor coadaptation for crawling. Nevertheless, if the thermal performance breadth of rubber boas is expanded, then activity at temperatures other than the optimal performance temperature for crawling speed may not substantially decrease performance.

The majority of studies concerning the thermal biology of reptiles have dealt with diurnal species. Studies of a wider variety of species (both phylogenetically and ecologically) are needed to obtain a general view of body temperature variation in reptiles (Avery, 1982; Huey, 1982; Peterson, 1987). By examining the thermal ecology of rubber boas, my study will extend our knowledge concerning the thermal biology of reptiles, both phylogenetically and ecologically. This is the first study of rubber boas using radiotelemetry. It is also one of the first studies to examine the thermal ecology of a nocturnal snake. Resulting information will lead to a more thorough understanding of the extent of coadaptation of behavior and physiological processes in nocturnal ectotherms.


Avery, R. A. 1982. Field studies of body temperatures and thermoregulation. pp. 93-166. In C. Gans and F. H. Pough (eds.), Biology of the Reptilia, vol. 12. Academic Press, N.Y.

Cunningham, J. D. 1966. Observations on the taxonomy and natural history of the rubber boa, Charina bottae. Southwestern Nat. 11:298-99.

Huey, R. B. 1982. Temperature physiology and the ecology of reptiles, pp. 25-91. In C. Gans and F. H. Pough (eds.), Biology of the Reptilia, vol. 12. Academic Press, N.Y.

Huey, R. B. and A. F. Bennett. 1987. Phylogenetic studies of coadaptation: preferred temperatures versus optimal performance temperatures in lizards. Evolution 41:1098-1115.

Lillywhite, H. B. 1987. Temperature, energetics, and physiological ecology, pp. 422-477. In R. A. Seigel, J. T. Collins, and S. S. Novak, editors. Snakes: ecology and evolutionary biology. McMillian, N.Y.

Peterson, C. R. 1987. Daily variation in the body temperatures of free-ranging garter snakes. Ecology 68:160-69.

Ross, R. C. 1931. Behavior of the Rubber Snake. Copeia 1931:7-8.

Stevenson, R. D., C. R. Peterson, and J. S. Tsuji. 1985. The thermal dependence of locomotion, tongue flicking, digestion and oxygen consumption in the wandering garter snake. Physiol. Zool. 58:46-57.

Wright, A. H., and A. A. Wright. 1957. Handbook of snakes of the United States and Canada. Ithaca, N.Y., Comstock Publishing. Pp. 1-1105.

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