Animal Adaptation and Acclimatization to Cold

Animal Adaptation and Acclimatizationto Cold

R.E. Phillips C.A. Watson

MANY PEOPLEARE confused by the two terms: adap- tors) and these animals avoid winter conditions by going tation and acclimatization.Adaptation is particularlycon- into a dormancy state. It is primarily the homeotherms Downloaded from http://online.ucpress.edu/abt/article-pdf/39/9/528/35964/4446077.pdf by guest on 02 October 2021 fusing because of its use in a non-scientific way in every- (warm blooded) chioneuphores and chioniophiles that day language. As scientists use the term, adaptation is exhibit some form of adaptation or acclimatization. biotic changes occurring within a population during a period of several generations (Burtonand Edholm 1955). Animal Acclimatization An organism develops adaptation to cold through a Acclimatization to cold, which is exhibited to some natural selection process. The development of heavy fur degree by all animals, can be demonstrated by gradual insulation is a good example of adaptation to cold. exposure of experimental subjects to increasingly cold Acclimatizationto cold is the sum of adjustments that conditions for a specified time. During this period, usually follow repeated and prolonged exposure to cold (Brown from two to six weeks, the organism gradually increases 1957). Exposure time for cold acclimatizationvaries from its abilityto survive in cold temperatures. species to species, but it usually falls within the range of Hart (1960) summarizes the phenomena associated from two to six weeks. Once the stimulus, in this case with cold acclimatization in the following related occur- cold, is removed, a new physiological adjustment is ex- rences: pected to occur. Gordon (1968) cites a classic example of adjustments in acclimatizationto cold in herring gulls. 1. A gradual increase in cold resistance; Cold acclimated gulls can walk on ice at freezing tem- 2. An increase in food consumption; peratures without any visible injury,but warm acclimated 3. An elevation of basal metabolic rate; gulls will immediately freeze their feet on ice. 4. An escalation of peripheral and sometimes core Acclimatization and adaptation, then, differ in two temperatures; major ways. Acclimatizationis a temporary adjustment to 5. A decrease in shivering; and a stimulus, but adaptation becomes established only after 6. An increase in non-shivering heat production; biochemical many generations of natural selection. Acclimatization 7. Other associated physiological and also requires a development period during exposure, changes. considerable but adaptation requires no apparent preparation time. It Each of these related occurrences merits appears likely that acclimatizationis related to adaptation attention when discussing cold acclimation. in that a continuously fixed acclimatization over several generations could result through a natural selection pro- The authors are high school cess in a population into an adaptation; or the abilityof a biology teachers in the St. population species to acclimate could be interpreted as James Assiniboia School a form of adaptation. Division, Winnipeg, Manitoba, Canada. Phillips, who teaches . at Westwood Collegiate, re- Terminology ceived a B.S.A. degree in 1967, a B.Ed. degree in 1974, Formozov (1946) classified animals into three basic and an M.Sc. degree in 1969 types: chionophobes (those that fear snow); chioneu- from the University of Mani- A- phores (those that are tolerant of snow); and chionio- toba. Watson, teaching at John Taylor Collegiate holds a B.Sc. degree (1963) and a B.Ed. degree (1966) from the same university. He com- philes (those that are snow lovers). Because the chiono- pleted his M.Ed. degree in 1976. Phillips and Watson were both mem- phobes escape the snow and winter by migrating the bers of a federally sponsored curriculum development project called latter two groups are of interest for adaptation and ac- Project Canada West (1970-75). They co-authored Environmental Studies: Teacher Resource Manual (Enviro-Concerns, Winnipeg) and climatization studies. Most chioneuphores are poikilo- recently completed another resource manual entitled Winter Investiga- thermic (cold blooded) or heterothermic (true hiberna- tions.

528 THEAMERICAN BIOLOGY TEACHER, DECEMBER 1977 of differences in metabolic rates. Apparently acclimatized rats could maintain a high metabolic rate for a prolonged 40 period of time during cold stress; non-acclimatized rats were metabolically unprepared and could not adjust quickly enough to cold shock. o 30 Metabolic rate increases for cold exposure depend in most instances, on the criticaltemperature of the animal. 00 Once temperatures are lower than the critical temperatures, the normal metabolism must make adjustments. $4 Increase in metabolism is partially caused by increased muscle activity in the form of shivering. The increase in metabolic rate due to shivering may be as high as 6 to 7 20 2 3 4 V$4 times the basal metabolic rate, for short periods of time U ~ ~ ~ Aelaio eprtr (Burton and Edholm 1955). Because there is such a temperature gradient between the organism and the VoJ~~~ ambient temperature, body shell and core temperature

must be maintained for homeotherms. According to Downloaded from http://online.ucpress.edu/abt/article-pdf/39/9/528/35964/4446077.pdf by guest on 02 October 2021 Keller (1960), body core hypothermia is prevented by a series of neural integrationsthroughout the body. Chilling FIGURE1. Upper and lower lethal temperature levels of the goldfish. of peripheral receptors activates hypothalmic activity that Lower limits are adjustable according to extent of acclimatization to cold. stimulates both central and peripheral thermogenesis (heat production) during acclimatizationto cold. Decreased shivering and eventual nonshivering thermogenesis results from increased heat production without Development of cold resistance has been shown in detectable muscle activity. Carlson (1960) regards non- some poikilotherms. Studies of cold resistance in goldfish shivering thermogenesis as an acclimatization phenom- (poikilotherms)by Fry (1947) have established upper and date has been shown in rats and to lower lethal temperature levels (fig. 1). The temperature enon, which to clearly in and man. between these two levels represents the temperature some degree rabbits,dogs, and biochemical range within which the acclimated fish can live independ- Numerous associated physiological noted with cold acclimatization. ently. During cold exposure, lower lethal limits can be changes have been adrenals and lowered gradually, thus enabling the fish to survive. Cold Endocrine glands such as the thyroid, pitu- with acclimatization. resistance has also been shown in insects by Asahina itary glands have been linked cold been shown con- (1959). Through a process of gradual acclimation to pre- Noradrenaline and ascorbic acid have and freezing temperatures, insects have eventually been able clusively to interplay with cold resistance. LeBlanc to survive at temperatures below the freezing point of Pouliot (1964) found some cold acclimation accompany- water. ing noradrenaline injections in experimental animals. Food consumption tends to increase significantly 0. Heroux (1960), on the basis of experimental evidence, during cold exposure and acclimatization. Blair et al. believes that noradrenaline plays the role of mediator in for acclimation to cold. (1951) in their study of rabbits at -300 C for many nonshivering thermogenesis research has also been done on ascorbic acid weeks found food intake increased from 60 g at 230 C Extensive to 105 g per day with no appreciable change in weight. in relationship to cold stress and resistance. Increased levels of ascorbic acid in the liver, spleen, and testis have Chinn et al. (1950) found food intake increased 60% to be correlated to in rat experiments at 40 C for 10 days. The type of nutri- been shown highly body adjustment ents also has some bearing on successful cold acclimati- to cold. occurs to some zation. Page (1957) in experiments with rats, noted the In summary, cold acclimatization varies beneficial effects of a high fat diet on acclimation. Fats in degree in all forms of animal life. Its complexity the diet serve as primary fuels for extra heat production according to the thermal status of the organism. Accli- in the cold. matization to cold would appear rather limited for poiki- it would be consid- Sellers et al. (1951b) have clearly shown a relation- lotherms although for homeotherms, ship between cold acclimatization and metabolic rate. ered rather complex. Extensive research, particularly A group of non-acclimatized rats had their coats clipped in the areas related to the intricatephysiological and bio- off and were then subjected to cold conditions. The non: chemical aspects of cold acclimatizationin homeotherms treated control group died within a few hours because of poses a major challenge for the future. excessive cold exposure. In comparison, cold acclimatized rats were clipped and subjected to cold. In most cases, the test group was able to survive for weeks under Animal Adaptation stress. Experimentalresults were interpreted on the basis When a terrestrialorganism is placed in cold conditions

ANIMALSAND COLD 529 species. Lethaltemperatures that could be endured be- HOMEOTHERM 40 came higherwith increase of age in all species. Gordon (1968) mentionsone other instanceof heter- othermy in homeotherms in what he calls regional hypothermia.Regional hypothermia exists at poorly 30 insulatedperipheral extremities. Hence peripheraltem- 0 peratureswill be lower than body core temperaturesin various species of mammalsand birds as illustratedin ' 20 figure3 (Irving1966). Some-external adaptative features have a bearingon cold adaptationfor mammalsand birds.There are numerous common physical features of inhabitantsof the 0~~~~~~~ northernarctic. Typical features, such as larger trunk, shorterappendages, and shorterears have been docu- mented through comparative studies to southern 10 20 30 40 counterpartspecies. Foot size is also muchlarger in many northernspecies. Larger,more distributedfeet create a Downloaded from http://online.ucpress.edu/abt/article-pdf/39/9/528/35964/4446077.pdf by guest on 02 October 2021 Environmental Temperature C "snowshoe"effect that enables many species to walk on top of the snow ratherthan in it. "Floaters,"as they are FIGURE 2. Relationshipof body core temperatureto environmental temperaturefor poikilotherms and homeotherms. called,expend very littleenergy by walkingon the snow. Some comparativeexamples of foot size are cited by Cunningham(1972). A lynx has a loading pressureof with the problem of maintaining a steep thermal gradient 28.4g per squarecentimeter; a house cat exerts 113.4g between its body core and the environment, it must per square centimeter. Other noted floaters are the either maintain or reduce its body temperature. Heter- snowshoehare, willow ptarmigan and polarbear. otherms and poikilotherms tend to reduce their core tem- Coat color is another interestingwinter adaptation. perature but homeotherms as shown in figure 2 tend to The white coat color has alwaysbeen considereda pro- maintain a constant body temperature (Gordon 1968). tective camouflageto white snow, but the white hair Poikilotherms, although somewhat acclimatized to follicleis also believedby some researchersto have insu- lowering of temperatures, must eventually contend with lative value. Coloredhair follicles have colored pigment freezing temperatures. Freezing temperatures can ulti- granulesthroughout the hairshaft but white hairfollicles mately lead to death, unless either warmer shelter or lack these pigment granules.Some researchersbelieve thatthe air some adaptive mechanism is available. Hardy (1972) spaces in the whitehair follicle where pigment and Salt (1957) discuss the natural occurrence of the granulesshould be could serve as an insulant.Consider- able has also antifreezing agent glycerol in terrestrial arthropods. controversy arisenas to whetherthe white colorationof arctic Studies indicate that insects with an abundance of glyc- homeothermsradiates less heat than erol can survive freezing although organisms deficient in the darkcoloration and thereforeis helpfulin preventing heat glycerol are highly susceptible to cold. Apparently glyc- loss. Svihla (1956) conducted experimentswith erol, the antifreezing agent, tends to protect the living tissue from the deleterious effects of freezing. Protection is thought to be achieved by ensuring that the increase Alr -30 C of electrolyte concentrate resulting from ice formation does not readily reach toxic levels and by elevating fluid 23 viscosity levels that minimize ice crystal formation. Under exceptionally favorable conditions further supercooling 7.5 , can occur by gradual reduction of temperature below freezing. Water has been known to super cool to -410 C before the appearance of ice crystals.Some insects during \Nk~~~ the winter dormancy are capable of supercooling 25 to 30 degrees below freezing point of water. Therefore, with 33 the combination of glycerol and the supercooling phen- 5 < /i/(///P(I omenon, many terrestrialarthropods can survive temperatures well below -400 C without freezing. 14 37 Adolph (1951a) detected hypothermic responses in several species of infant mammal homeotherms. Appar- ently many newborn mammals can survive body temperatures that cannot be tolerated by adults of the same FIGURE 3. Regionalhypothermia evident for the Eskimo dog (husky).

530 THEAMERICAN BIOLOGY TEACHER, DECEMBER 1977 10 tissue. Normal body fat tends to become hard and brittle when exposed to cold. Another type of fat has been

white fox found in the colder body extremities of various organ- 8. isms. Irving (1966) mentions the abundance of this low wolf freezing point fat in the legs and feet of caribou. These ~~~~grizzly -~~~~~~~~~~~ lipid oils enable the legs and feet to be pliable at sub-zero bear ~~~rabA't~~6 *red fox temperatures. The Alaskan Red Fox also relies on this in its foot pads. * dog *polar unique oil for suppleness and flexibility o beaver bear A practical example is the oil extract from the domestic

ita .marten bovine hoof, which has long been used by humans as a leather preservant for winter footwear. squirrelsire6 o ~~~~~~~seal *lemming Scholander (1957d) has discovered a remarkable 2, weasel' piece of biological engineering that some organisms have shrew devised to protect poorly insulated body extremities. A homeothermic bird with this protective mechanism can

2 4 6 8 stand in ice cold water for an entire day without experi-

Thickness of fur (cm.) encing any appreciable loss of body heat. A barefooted Downloaded from http://online.ucpress.edu/abt/article-pdf/39/9/528/35964/4446077.pdf by guest on 02 October 2021 human being would have little chance of withstanding FIGURE 4. Comparative insulation values for various northern inhabitants.

albino rats and dyed black rats showing that coloration had no effect on the conservation of heat or the preven- tion of radiation. Ryder (1973) concurs with Svihla's findings in reaffirmingthat no relationship exists between coat color and the amount of heat lost. +~~ Many researchers agree that insulation represents the major homeothermic adaptation to cold resistance. In- sulation in the form of fur for terrestrialanimals and fat in aquatic animals enables core body temperatures to be maintained even in the coldest environmental conditions. veirt! ey Comparative studies for insulation are possible by using an arbitraryinsulation measurement called the clo unit. Burton and Edhold (1955) define the clo unit as the insulation provided by the clothing that would be worn at room temperature of 200 C. Apparently this unit has gained wide acceptance because of its ready appreciation FIGURE 5. The "Wonderful Net," a counter current blood exchange of effective thermal insulation. Irving (1966) in figure 4 in peripheral extremities of various organisms. illustrates a comparison of insulation values for various northern inhabitants. Clothing in humans, also classified this cold stress for any length of time. The difference is as having insulative value, can be increased to a maxi- that the bird is equipped with a "rete mirabile," more mum of 6 clo units because any additional clothes would commonly referred to as a "wonderful net." The wonder- impairfree movement. ful net (fig. 5) is basically a counter current exchange in Upon exposure to cold conditions, homeotherms blood circulation located in body extremities such as adjust immediately by a series of reflex responses, medi- limbs, fins, and tail. Special networks of blood vessels ated by cold receptors in the skin, designed to conserve consisting of arteries and veins act as a barrierto the es- heat. Richards (1973) lists three notable occurrences cape of heat in the direction of the afferent warm current associated with cold exposure: flow. Heat moves through conductance from the warm 1. A maximum constriction of peripheral blood ves- arterial flow to the cool venous flow destined for the sels. warm body core. The result is that a warm body core tem- 2. An erection of hair or feathers. perature is maintained with a contrastingly low tempera- 3. A reduction of functional surface area by change of ture of body extremities. Fortunately, extremities such as posture. the limbs are able to function effectively at the lower tem - Only after the above responses are determined inade- peratures. Temperature gradients between the inner core quate will the metabolic rate increase. and the peripheral extremities may be as much as 300 C. Researchers have also discovered the existence of So far it has been confirmed that whales, seals and many another type of fat besides the internal subcutaneous fatty long-legged wading birds possess such retes.

ANIMALSANDCOLD 531 A vast number of arctic animals lack the "wonderful net" and must rely on an alternative for poorly insulated extremities. In most of these animals (ducks, geese, sea 500 Antelope Ground gulls, fox, husky) the fur or feather insulation is so effec- Squirrel Blossom tive that they use their poorly insulated areas for hea.t 4o00 lOOg dissipation. Bat The only alternative to improved insulation to cold 200g conditions is the adjustment in metabolic heat production. 300

Dependence on this protective adaptation to cold ap- Alaskan pears to be directly related to the size of the individual or- Red Squirrel ganism. Hardy (1972) discusses the metabolic responses r 200 230 g of larger arctic animals to cold. Apparently most of the larger inhabitantsof the north rely on insulation to protect laskan 100 Red Fox them. For instance the arctic white fox can maintain its 5 Kg basal metabolic rate even when it is subjected to temperatures around -400 C. Foxes have been known to endure

-40 -20 020 40 Downloaded from http://online.ucpress.edu/abt/article-pdf/39/9/528/35964/4446077.pdf by guest on 02 October 2021 ambient temperatures as low as -80? C for an hour with- 0 out experiencing any hypothermia. Temperature C Scholander et a!. (1950a) discuss the variation in critical temperatures for homeotherms subjected to cold con- FIGURE 6. Criticaltemperatures for various mammals. ditions. All homeothermic organisms have a criticaltemperature that represents the temperature at which meta- lead to a greater understanding of biotic cold protection in bolic rate changes. Temperatures below the critical tem- the environment. perature for a given organism cause an increase in metabolic heat production as shown in figure 6 (Gordon 1968). Larger arctic mammals with an abundance of insulation generally have critical temperatures below References -300 C. Smaller arctic species with a limited capacity for ADOLPH, E.F. 1951(a). Responses to hypothermia in several insulation have a much higher criticaltemperature. Many species of infant mammals. Am. J. Physiol. 166:75. of the birds (ptarmiganand snow bunting) minimize their . 1951(b). Some differences in responses to low temper- metabolic heat requirements by burying themselves in the atures between warm-blooded and cold-blooded vertebrates. snow overnight. Am. J. Physiol. 166:92. ASAHINA, E. 1959. Prefreezing as a method enabling animals One last consideration in regard to cold adaptation to survive freezing at an extremely low temperature. Nature involves the relationship of brown fat to cold resistance. 184(4691):1003. Research evidence has indicated that brown fat is related BLAIR, J. R., DIMITROFF,J.M., and HINGLEY, J.R. 1951. in some way to hibernation, insulation, and metabolism. Acquired resistance to cold in rabbit and rat. Fed. Proc. Brown adipose tissue represents a form of insulative 10. BROWN, G.M. 1957. Vascular physiology of the Eskimo. adaptation which is present in many hibernatingand non - Revue Canadienne De Biologie 16(2):279. hibernating mammals. Since brown fat is associated with BURTON, A.C. and EDHOLM, O.G. 1955. Man in a cold en- cold climatic conditions, it would be reasonable to assume vironment. New York: Hefner Publishing Company. that brown fat has evolved as specialized adipose tissue CARLSON, L.D. 1960. Nonshivering thermogenesis and its related to cold protection. Brown adipose tissue is usually endocrine control. Fed. Proc. 19, Suppl. No. 5:25. CHAFFEE, R. R. J., ALLEN, J. R., CASSUTO, Y., and SMITH, found in the scapular, axillaryor thoracic depot regions in R. E. 1964. Biochemistry of brown fat and liver of cold accli- the body. Although numerous in vivo and in vitro studies mated hamsters. Am. J. Physiol. 207(6):1211. have been performed on this tissue, relatively little is CHINN, H.E., OBERST, F.W., BYMAN, B., and FENTON, K. understood about this specialized tissue. Researchers 1950. Biochemical changes in rats exposed to cold. USAF have established that brown fat is responsible for higher School of Aviation Medicine, Randolph Field, September 1950, No. 21-23-027. respiration rates than white adipose tissue during cold CUNNINGHAM, H.A. 1972. A bit about snow. Conservation exposure. The presence of brown fat does not always Comment, January 1972. guarantee more favorable responses to cold. Morrison DESMARAIS, A. 1960. Ascorbic acid in cold acclimation. and Allen (1962) attempted brown fat implants into white Fed. Proc. 19, Supplement No. 5:88. mice without success. Implanted mice made no significant FORMOZOV, A.N. Snow cover as an integral factor of the environment and its importance in the ecology of mammals response to changes in temperature. and birds. Originally published as Materials for fauna and In conclusion, although many of the intercomplexities flora of the U.S.S.R., New Series Zoology 5(20):1. English of cold resistance in animals have not yet been discov- translation: 1969. Occasional Publication No. 1, Boreal In- ered, increased interest in the mechanisms related to stitute, University of Alberta, Edmonton. acclimatization and adaptation to cold will undoubtedly (Concluded on p. 538)

532 THEAMERICAN BIOLOGYTEACHER, DECEMBER 1977 was no exception. "Whatcan you tell me about dande- and subarcticbirds and mammals.J. Appi. Physiol. 6(11): lions?"generated studies of dandeliondensity in various 667-680. soil and lightintensity samples, chemical analyses of the IRVING, L. 1966. Adaptation to cold. In Vertebrate adapta- dandelion,investigations of starch-makingand stomata tions. Readings from Scientific American. 1968. San Fran- cisco:W.H. Freeman and Companv. sites, and comparativestudies of leaf arrangementpat- - 1972. Arctic life of birds and mammals: New York: terns and seed dispersalmechanisms. A novice gourmet Springer-Verlag. offered salads made from young leaves and a brew of KELLER,A. D. 1960. Peripheraland centralcontrol of cold roasted dandelionroots. Investigationsare as individual stimulatedthermogenesis. Fed. Proc. 19, Suppl.No. 5:30. as the students themselves, and we are constantly KINTINGE,W. R. 1957. The effect of generalchilling on the vasodilatorresponse to cold.J. Physiol.139:497. amazedby the diverseapproaches class membersuse. In LEBLANC,J. and PAULIOT,M. 1964. Importanceof nor- this case, the dandelion,the layman'slawn pest, became adrenalinein cold adaptation.Am. J. Physiol.207(4):853. a marvelof ecological adaptationsas students pursued MORRISONP. and ALLEN,W. T. 1962. Temperaturere- theirprojects. sponse of white mice to implantsof brown fat. J. Mamm. have found 43(1):13. Kitsare not used by our students,and we PAGE,E. 1957. Body compositionand fat depositionin rats that the magic of commercialkits has been replacedby acclimated to cold. Revue Canadienne De Biologie 16(2):

increasedstudent understanding. Understanding is time- 269. Downloaded from http://online.ucpress.edu/abt/article-pdf/39/9/528/35964/4446077.pdf by guest on 02 October 2021 consuming,however; the analysesof watersamples, for PHILLIPS,R.E. and WATSON,C.A. 1976. A highschool snow example, meant that students had to have background ecology unit. Amer. Biol. Teacher 38(1):16. RICHARDS, S.A. 1973. Temperature regulation. London, in such areas as titrationtheory and the physiologyof England:Wykeham Publishers Ltd. bacteria.Much of thislearning was accomplishedthrough RYDER,M. 1973. Hair. London, England:Edward Arnold student-instructorconferences. We found that few stu- PublishersLtd. dents chose to go throughthe motionsof an experiment SALT,R.W. 1957. Naturaloccurrence of glycerolin insectsand its relationto their abilityto survive freezing.Canad. Ent. withoutknowing why they were doingit. Withample time 89:491. to learnand a concrete,immediate opportunity to apply SCHOLANDER,P.F., HOCK, R., WALTERS,V. and IRVING, new theories,students find learning an excitingchallenge. L. 1950(a). Adaptationto cold in arcticand tropicalmam- We did not use a textbookfor this course because we mals and birds in relationto body temperature,insulation could not find one that would meet our needs. Resource and basalmetabolic rate. Biol. Bull. 9(2):259-271. -. HOCK R., WALTERS, V. JOHNSON, R. and IRVING, personnel, mimeographedmaterials developed for the L. 1950(b).Heat regulation in some arcticand tropicalmam- course, and librarymaterials provided us with greater malsand birds.Biol. Bull. 99(2):237-258 flexibility.Many times we found the best materialsright , WALTERS,V., HOCK,R., and IRVING,L. 1950(c). under our noses: mini-ecosystemsof interactionsof Body insulationof some arctic mammals and birds.Biol. species and populationsuccessions when bacteriaand Bull.99(2):225. mold invade a yeast culture prepared for population . 1957(d). The wonderful net. Sci. Amer. 196:97. SELLERS,E.A. REICHMAN,S. and THOMAS,N. 1951(a). growthstudies; diluted soil samplesincubated for strepto- Acclimatizationto cold:natural and artificial.Am. J. Physiol., mycin;birthrate studies of protozoansthat grew in a brine 167,644. shrimpsolution. Our investigations have never gone bad; , YOU,S.S. and THOMAS,N. 1951 (b).Acclimatization they have gottenprogressively better. and survivalof rats in the cold: effects of clipping,of adren- By using the main concepts of diversityand dynamic alectomyand thyroidectomy.Am. J. Physiol.165:481. STEEN,J. 1958. Climaticadaptation in small northernbirds. interaction,and by allowing surprisesand conflictsto Ecology 39(4):625. occur,any high school can devise a successfulecological STEINER,G. and CAHILL,Jr. G.F. 1964. Brownand white program.Each ecologicalsetting is unique;treasure that adipose tissue metabolismin cold exposed rats. Am. J. uniqueness.Diversity leads to excitementand challenges Physiol. 207(4):840. in learning. SVIHLA,A. 1956. The relationof colorationin mammalsto low temperature.J. Mamm.37(3):378.

Animals and Cold ... from p. 532 Guideto ScientificTestimony FRY F.E.J. 1947. Effects on animal activity. Publication of the The American Institute of Biological Sciences has Ontario Fish Research Laboratories. recently published its 1977 version of A Guide to Pro- GORDON, M.S. 1968. Animal function: principles and adaptation. New York: MacmillanCompany. viding Scientific Testimony. The new guide includes a HARDY R.N. 1972. Temperature and animal life. London, section on the changes in the 1976 Tax Law that affect England: Edward Arnold Publishers Ltd. the "Lobbyingrights" of scientific organizations. It is de- HART, J.S. 1960. Energy metabolism during exposure to cold. signed to assist the individual scientist and the leader- Fed. Proc. 19, Suppl. No. 5:15. ship of scientific organizations in HEROUX, 0. 1960. Thermogenesis in the acclimated animal. sharing scientific infor- Fed. Proc. 19. Suppl. No. 5:43. mation and viewpoints with legislators. The Guide is IRVING, L. and KROG, J. 1954. Body temperature of arctic available at $2.50 per copy ($2 for AIBS members).

538 THEAMERICAN BIOLOGY TEACHER, DECEMBER 1977