Activity of a specialized insectivorous mammal (Myrmecophaga tridactyla) in the Pantanal of Brazil

The purpose of this study was to correlate the activity and habitat use of a large and ecologically specialized mammal ( Myrmecophaga tridactyla ) with the time of day and minimum daily temperature in Brazil's Pantanal wetland. Seven giant anteaters were fitted with very high frequency (VHF) radio transmitters and monitored from March to December 2001. The animal's state of activity or rest, time and ambient temperature were recorded in different patches of the study site, which were covered by a mosaic of vegetation types and several ponds. Whenever a giant anteater was inside a forest patch, the temperature inside and outside of the patch was also recorded. The temperatures throughout the day were recorded by the meteorological station at the study site. The period of greatest activity of giant anteaters started at 18:00 h on hot days, but whenever the daily minimum temperature declined, the species' activity began earlier. Giant anteaters use predominantly forest habitats for rest and open habitats for activity. The forest patches work as a temperature buffer, because they are cooler than the matrix of open habitats during the hot hours of the day and warmer than the matrix during the cold hours. Although the giant anteater is known to be associated with open habitats, this study indicates the need of preserving forest patches for the conservation of this species.     

Fluctuations in the tympanic membrane temperatures of non-restrained captive giant anteaters and southern tamanduas

Members of the family Myrmecophagidae (i.e. anteaters) show a variety of anatomical and behavioural adaptations to deal with their low-energy diet; for example, they all have low body temperatures in comparison with other eutherian mammals. In this study, we investigated the tympanic membrane temperatures ( T _mt) of two giant anteaters and three southern tamanduas, housed in captivity and exposed to natural climatic variations in temperature, using an infrared thermometer. Additionally, we measured external dorsal temperature ( T _d), air temperature ( T _a), substrate temperature ( T _s) and whether the subject was active or not. To understand the effect of time of day on these variables, we recorded them, on the hour, over four 24-h cycles for each animal during which the subjects were non-restrained within their enclosures. The results show that both giant anteaters and southern tamanduas allow their T _mt to reduce between 4.0 and 6.5 °C when they are sleeping. Furthermore, linear regressions between T _mt and T _a or T _s showed that the giant anteaters were much more affected by T _a and T _s than the southern tamanduas. Both species also showed higher T _mt when active (comparing subjects active and inactive at the same T _a). Both species appear to use shallow torpor during a normal 24-h cycle probably as a means to economize energy. The torpor in giant anteaters occurred during the night when asleep, whereas in the southern tamanduas it occurred at any time of day when asleep. The giant anteaters appeared to be more directly affected by environmental temperature than the southern tamanduas.     

Seasonal variation in diel activity and microhabitat use of an endemic New Zealand stream-dwelling galaxiid fish

1. Seasonal variation in microhabitat use and activity of 14 giant kokopu Galaxias argenteus, a drift‐feeding galaxiid fish, was compared using radiotelemetry. 2. During winter giant kokopu predominantly used low velocities and intermediate depths by night and day. Activity recorded during 24 and 72 h periods indicated that fish were consistently active at night and inactive during the day. Activity data corresponded with point‐in‐time habitat use data, both of which indicated that fish were concealed amongst cover during the day and used open water habitats at night. 3. During summer, giant kokopu used higher water velocities, shallower depths and coarser substrata, particularly at night but also occasionally during the day relative to winter. Giant kokopu were active by both day and night in summer, although periods of activity were less defined and less predictable than during winter. 4. Adults used predictable home reaches at base‐flow, with most individuals repeatedly using of one or two cover locations within their ‘home’ reach. Reaches used by fish were relatively short (rarely exceeding 26 m) irrespective of season and always included a single pool‐riffle sequence. 5. Diel and seasonal behaviour of giant kokopu was generally comparable with that exhibited by other drift feeding fish species in small temperate streams. However, the nocturnal activity of giant kokopu contrasts with activity patterns in various salmonids, indicating that the impact of predation by different drift feeding fish may vary considerably.     

Huddling house sparrows remain euthermic at night,and conserve body mass

An advantage of huddling in the cold is that the individual animals involved can maintain body temperature while saving energy. Since house sparrows Passer domesticus biblicus store little fat, but inhabit relatively cold climates, we tested the hypothesis that they huddle at night. While recording body temperature and body mass of 18 house sparrows when they were either caged individually, or free in an aviary, we observed that when free in the aviary, the sparrows huddled at low ambient temperatures and more birds huddled, in tighter and tighter formation, as ambient temperature decreased. However, their body temperatures were not significantly different from when they spent the night individually caged. When free to huddle, the birds lost significantly less body mass during the course of a day than when individually caged. This reduction in body mass loss may be of particular importance during periods of adverse environmental conditions, especially for small birds that manage their energy budgets on a daily basis.     

Effect of Season and High Ambient Temperature on Activity Levels and Patterns of Grizzly Bears (Ursus arctos)

Understanding factors that influence daily and annual activity patterns of a species provides insights to challenges facing individuals, particularly when climate shifts, and thus is important in conservation. Using GPS collars with dual-axis motion sensors that recorded the number of switches every 5 minutes we tested the hypotheses: 1. Grizzly bears (Ursus arctos) increase daily activity levels and active bout lengths when they forage on berries, the major high-energy food in this ecosystem, and 2. Grizzly bears become less active and more nocturnal when ambient temperature exceeds 20°C. We found support for hypothesis 1 with both male and female bears being active from 0.7 to 2.8 h longer in the berry season than in other seasons. Our prediction under hypothesis 2 was not supported. When bears foraged on berries on a dry, open mountainside, there was no relationship between daily maximum temperature (which varied from 20.4 to 40.1°C) and the total amount of time bears were active, and no difference in activity levels during day or night between warm (20.4–27.3°C) and hot (27.9–40.1°C) days. Our results highlight the strong influence that food acquisition has on activity levels and patterns of grizzly bears and is a challenge to the heat dissipation limitation theory.     

Giant Anteater Population Density Estimation and Viability Analysis Through Motion-Sensitive Camera Records

Giant anteater (Myrmecophaga tridactyla) populations are decreasing throughout their range. We tested a methodology for individual identification using camera records and fur patterns to estimate the giant anteater population in a protected area of the Brazilian Cerrado. We identified 9 adult individuals and successfully modeled population abundance and density. Our models estimated an adult population of 16.8 (range = 15–19) giant anteaters through a mark-resight approach and 12.5 individuals (range = 9.7–25.5) through a spatially explicit capture-recapture approach. Density estimates were 0.3–0.4 animals/km². Using these estimates, we performed a population viability analysis to understand and predict this population's future. We modeled scenarios without direct effects and models simulating a double carrying capacity and the supplementation and removal of individuals. Even in the more optimistic scenarios, the population is predicted to decreases over time, with ≤8 individuals remaining in 100 years. Given the study area surroundings, realistic models include removals of giant anteaters in the population. Identification of giant anteaters using cameras can inspire conservationists to acquire population data throughout its distribution and obtain population trends to evaluate the species' conservation status. Individual identification of giant anteaters using a motion-sensitive camera design is feasible, opens new avenues for population analyses, and allows the study of population trends in difficult regions. © 2021 The Wildlife Society.     

Interactive effects of temperature and photoperiod on the daily activity and energy metabolism of pouched mice (Saccostomus campestris: Cricetidae) from southern Africa

The daily activity and energy metabolism of pouched mice (Saccostomus campestris) from two localities in southern Africa was examined following warm (25 °C) and cold (10 °C) acclimation under long (LD 14:10) and short (LD 10:14) photoperiol. There was no differential effect of photoperiod on the daily activity or metabolism of pouched mice from the two localities examined, which suggests that reported differences in photoresponsivity between these two populations were not the result of differences in daily organisation. Neverthe-less, there was a significant increase in metabolism at 10 °C, irrespective of photoperiod, even though seven cold-acclimated animals displayed bouts of spontaneous torpor and saved 16.4–36.2% of their daily energy expenditure. All but one of these bouts occurred under short photoperiod, which suggests that short photoperiod facilitated the expression of torpor and influenced the daily energy metabolism of these individuals. As expected for a noctureal species, the amount of time spent active increased following acclimation to short photoperiod at 25 °C. However, there was a reduction in mean activity levels under short photoperiod at 10 °C, possibly because the stimulation of activity by short photoperiod was masked by a reduction in activity during bouts of spontaneous torpor. Cold temperature clearly had an overriding effect on the daily activity and metabolism of this species by necessitating an increase in metabolic heat production and eliciting spontaneous torpor which overrode the effect of short photoperiod on activity at an ambient temperature of 10 °C.Abbreviations 3-ANOVA three-way analysis of variance - %ACT percentage of time spent active - ADMR average daily metabolic rate - M _b body mass - MR metabolic rate - MR_dark metabolic rate recorded during the dark phase - MR_light metabolic rate recorded during the light phase - NST non-shivering thermogenesis - RQ respiratory quotient - STPD standard temperature and pressure, dry - T _a ambient temperature - T _b body temperature - VO₂ oxygen consumption     

Thermal biology, torpor use and activity patterns of a small diurnal marsupial from a tropical desert: sexual differences

Many small desert dasyurids employ torpor almost daily during winter, because cold nights and low food availability impose high energetic costs. However, in Western Australia the arid zone extends into tropical, coastal regions, where winter temperature conditions are far less severe. We studied the thermal biology and activity patterns of free-ranging kaluta (~27 g), a dasyurid restricted to these tropical spinifex deserts, during the Austral winter (June–July) and in addition quantified activity patterns in captivity. Unlike most dasyurids, wild and captive kalutas were almost exclusively diurnal and retreated into underground burrows during the night. Despite being active during the warmer part of the day, kalutas entered torpor daily. However, torpor patterns differed remarkably between males and females. While females spent most of the night torpid at body temperatures (T _b) as low as 21°C, close to soil temperature, males entered multiple short and shallow bouts (T _b > 25°C) during the night. Males also maintained higher T _bs during the early morning when active, occupied larger home ranges and covered greater distances while foraging than females. Hence, males appear to expend more energy than the similar-sized females both while foraging and during the rest phase. We propose that physiological as well as behavioural preparations for the September mating season that culminate in a complete male die-off might already impose energetic costs on males during winter.     

圈养大熊猫同时哺育双胞胎行为观察

2003 年,圈养大熊猫“梅梅”首例哺育成活一胎二仔,通过对其近半年的育幼行为观察,结果发现:1) 母兽主要以同时衔2 仔、同时衔和抱2 仔二种方式将幼仔抱入怀中哺育;60 d 内, 育幼姿势以坐位为主,倦卧其次, 其它姿势更少, 其中坐位随日龄增加逐渐减少, 倦卧变化不大。2) 母兽活动时间在产仔当天最多, 之后显著下降并维持在35.2 ± 0.6% 的低水平, 47 d 后再缓慢上升到108 d 后的54.8 ± 0.9% 。3) 双胞胎幼仔间哺乳的日均次数和时间无显著差异。4) 7 d 内2 幼仔“仔在母身上” 的时间占100%, 21 ～ 23 d 后显著减少, 而“母体盖仔”、“仔在母身边”和“母仔自然分离”的时间显著增加, 但“母体盖仔” 的时间在32 d 左右后又显著减少;双胞胎分别在与母兽的此四种位置变化的时间上无显著差异。5) 母兽的活动、幼仔哺乳日均次数、“母仔自然分离”在全天的日均时间分布有峰、谷变化。6) 随幼仔活动能力的逐渐增强,幼仔离“育幼窝”的距离也逐渐增加,双胞胎幼仔离“育幼窝”的远近也有差别。7)母兽分别与其雄性双胞胎幼仔玩耍的时间有显著差异,而两幼仔自玩的时间无差异,此两双胞胎自玩和一起玩耍所用时间远大于分别与母兽玩耍的时间。该研究丰富了大熊猫育幼行为内容,并为以后的大熊猫双胞胎育幼提供了可供参考的行为资料。     

Partial arousals from hibernation in a pair of common dormice,Muscardinus avellanarius (Rodentia,Gliridae), in their natural hibernaculum

Summary A pair of common dormice discovered while torpid in their natural hibernaculum on December 5, was studied continously outdoors, exposed to natural fluctuations in temperature and rainfall. Temperature inside and outside the nest ball and motor activity were recorded. The first emergence from hibernaculum occurred on March 4, after which the dormice were daily active, chiefly during evening and night hours. Nest departures lasted on average 10.5 h (6.5–14 h) per day.During the 88 days while the animals remained in the hibernaculum ambient temperature ranged from -5° to 8.5° C. Nest temperature never fell below zero, being chiefly 1.0°C above ambient temperature during 68 of these days and thus reflecting deep hibernation in both animals. However, on 19 occasions nest temperature was raised steeply from average 5.6°C (2.0–8.0°C) to average 23.0°C (17.5–32.5°C). These increases of nest temperature, lasting roughly 4 h (3–8 h) are interpreted as partial arousals. The total duration of partial arousals was 76 h, i.e. 3.6% of the time during which the animals remained consistently in the nest.The interarousal time varied, being 16 days at the most and 12 h at the least. The frequency of arousals increased with rising maximum values of ambient temperature, and partial arousals never were recorded on days when temperature remained below 2°C. It is believed that partial arousals correspond to the periodic or spontaneous arousals previously recorded in laboratory experiments of some other hibernating mammals. However, the energetic expenditure seems to be smaller during periodic arousals because of their shorter duration and the fact that no departure from the hibernaculum occurs.Possible mechanisms governing partial arousals are discussed. As these events chiefly occurred during night they may partly be controlled by an inherent time sense.     

The Difference Between Activity When in Bed and out of Bed. III. Nurses on Night Work

Eight nurses have been studied during rest days and three successive night shifts. Measurements of wrist activity have been made and used to assess the extent to which the pattern of daily activity changes between control (rest) days and days involving night work. One analysis considered wrist activity during time spent in bed; this appears to decrease in parallel with the amount of time in bed that is lost during night work but, when this effect is corrected for, there is greater activity during time spent in bed in the daytime compared with control days (when time in bed is during the night). The dichotomy of activity (between lower values during time spent in bed and higher values when out of bed) also decreases if time in bed is during the daytime while on night shifts. These changes in the amount of wrist activity and the dichotomy between activity in and out of bed are related to the changed quality and quantity of sleep that has been measured by self-report questionnaires and the sleep EEG. It is concluded that results from wrist actimetry can provide valuable information regarding the process of adjustment to night work, and that its convenience (to subject and experimenter), coupled with the new analytical approaches described here, make it a viable method for field studies. (Chronobiology International, 13(4), 273-282, 1996)     

Hibernation by a free-ranging subtropical bat (Nyctophilus bifax)

Knowledge about torpor in free-ranging subtropical bats is scarce and it is widely believed that low and stable ambient temperatures are necessary for prolonged torpor. We present temperature-telemetry data from free-ranging male (n = 4) and female (n = 4) subtropical vespertilionid bats, Nyctophilus bifax (~10 g), exposed to pronounced daily fluctuations of ambient temperature. All bats used torpor on every day in winter and both males and females exhibited multi-day torpor bouts of up to 5.4 days. Although females were larger than males, patterns of torpor were similar in both sexes. Torpor use was correlated with prevailing weather conditions and, on days when bats remained torpid, maximum ambient temperature was significantly lower than on days when bats aroused. Moreover, the duration of interbout normothermic periods at night increased with increasing average nightly ambient temperature. Skin temperature of torpid bats varied by 10.2 ± 3.6°C day⁻¹ (n = 8, N = 47) and daily minimum skin temperature was positively correlated with the daily minimum ambient temperature. Our study shows that prolonged torpor is an important component of the winter ecology of a subtropical bat and that torpor and activity patterns of N. bifax predominantly reflect prevailing weather conditions.     

Night roosting and the nocturnal time budget of the little brown bat,Myotis lucifugus: Effects of reproductive status,prey density,and environmental conditions

Summary The insectivorous bat Myotis lucifugus typically apportions the night into two foraging periods separated by an interval of night roosting. During this interval, many bats occupy roosts that are used exclusively at night and are spatially separate from maternity roosts. The proportion of the night which bats spend roosting, and thus the proportion spent foraging, vary both daily and seasonally in relation to the reproductive condition of the bats, prey density, and ambient temperature. A single, continuous night roosting period is observed during pregnancy. During lactation, females return to maternity roosts between foraging bouts, and night roosts are used only briefly and sporadically. Maximum use of night roosts occurs in late summer after young become volant. Superimposed upon these seasonal trends is day-to-day variation in the bats' nightly time budget. Long night roosting periods and short foraging periods are associated with cool nights and low prey density. This behavioral response may minimize energetic losses during periods of food scarcity.     

Space use by giant anteaters (Myrmecophaga tridactyla) in a protected area within human‐modified landscape

1. Spatial ecology data are essential for conservation purposes, especially when extinction risk is influenced by anthropogenic actions. Space use can reveal how individuals use the habitat, how they organize in space, and which components are key resources for the species.
2. We evaluated the space use and multiscale habitat selection of giant anteaters (Myrmecophaga tridactyla), a vulnerable Neotropical mammal, in a Cerrado site within a human‐modified landscape in southeastern Brazil.
3. We used GPS transmitters to track eight anteaters in the wild. With the resulting dataset, we estimated home range and core‐area sizes and then used two overlap indexes. We assessed habitat selection by compositional analysis and analyzed events of spatio‐temporal proximity.
4. The average Brownian bridge kernel estimate of home range size was 3.41 km² (0.92–7.9). Regarding home range establishment, five individuals showed resident behavior. Males (n = 4) had larger home ranges and were more active than females (n = 4). Despite the spatial overlap of home range (above 40% in four dyads), maximum temporal space sharing was 18%. Giant anteaters were found in proximity. Habitat selection favored savanna, and exotic timber plantation was always avoided. Roads and built‐up areas were selected secondarily at the landscape level.
5. The selection of anthropogenic sites denotes behavioral plasticity regarding modified habitats. However, the high selectivity for savanna, at all levels, demonstrates a high dependence on natural habitats, which provide the necessary resources for the species. The recurrent proximity of male–to‐female anteaters may indicate reproductive behavior, which is essential for maintaining this isolated population.

     

Note on the diet of the jaguar in central Brazil

Diet of the jaguar Panthera onca in the Cerrado, central Brazil, was investigated based on a sample of genetically identified jaguar scats. At least nine prey species were observed in 35 scat samples. Giant anteaters Myrmecophaga tridactyla contributed more than 75 % of biomass to the observed diet. Tapirs Tapirus terrestris and peccaries Tayassu pecari and Pecari tajacu contributed approximately 6 % to jaguar diet each, and small mammals contributed least to the jaguar diet. At 0.121, dietary niche breadth was narrower than reported in most other studies. Due to their physical characteristics and abundance, giant anteaters are likely the most profitable prey for jaguars in Emas National Park, and as an important prey, they should be included in jaguar conservation efforts.     

Comparative activity pattern during foraging of four albatross species

The activity patterns of foraging Yellow‐nosed Diomedea chlororhynchos, Sooty Phoebetria fusca, Black‐browed D. melanophris impavida and Grey‐headed Albatross D. chrysostoma were compared using loggers recording the timing of landing and take‐offs, as well as the duration of bouts in flight or on the water, and the overall time spent in flight. The four species spent a similar proportion of their foraging time in flight (56–65%). During the day they were mostly flying (77–85% of the daylight period) whereas at night they were mainly (61–71%) sitting on the water. The amount of time spent in flight during the daytime foraging period was related to the amount of time spent sitting on the water at night. Differences between species occurred in the duration of bouts in flight and on the water as well as in the frequency of landings and in the time elapsed between successive landings. Yellow‐nosed Albatrosses were more active than the other species, with more frequent short bouts in flight and more frequent successive landings at short intervals. Sooty Albatrosses landed or took‐off less often than the other species and were more active just before dusk. Black‐browed and Grey‐headed Albatrosses were more active at night, especially the first part of the night and far from the colonies. Their trips consisted of a commuting part and a foraging part. Black‐browed Albatrosses landed more often during the foraging than the commuting part, suggesting that they were not searching when travelling. The study suggests that there is no fundamental difference between the overall activity budgets of the four species although they show distinctive diet, morphology and life history traits. The differences observed between the four species were related mainly to differences in foraging technique. Comparison with the Wandering Albatross, the only species for which data were available previously, suggest that this larger species might differ completely in foraging technique from the smaller albatrosses.     

Effect of masking the parietal eye on the diurnal activity and body temperature of two sympatric species of monitor lizards, Varanus s. salvator and Varanus b. nebulosus

 Five water monitor lizards, Varanus salvator salvator, and four clouded monitor lizards, Varanus bengalensis nebulosus, were caught on Tioman island in Malaysia. A radio-thermistor transmitter was implanted into the buccal cavity of each animal, and they were released into an enclosure measuring 5.5 × 6.5 metres. The lizards were observed for 9 and 8 days, respectively, before and after the parietal eye was covered with aluminium foil. With uncovered parietal eye, both species showed a clear diurnal rhythm, being active only during day time. After covering the parietal eye, the mean locomotor activity of five V. s. salvator decreased from 791 to 107 min · day^–1 but remained unchanged around 850 min · day^–1 for V. b. nebulosus. The mean duration of locomotor activity decreased in V. s. salvator and V. b. nebulosus after the parietal eye was covered, but V. b. nebulosus maintained its locomotor activity by increasing the number of locomotor bouts. The water monitor spent very little time on thermoregulation. Its body temperature ranged between 26.3 and 28.4 °C, which decreased after the parietal eye was covered. The clouded monitor thermoregulated around 28.8–36.0 °C, which remained unchanged after the parietal eye was covered. In both species, there was a strong correlation between body temperature and ambient temperature. Behavioural abnormalities were recorded among V. s. salvator with covered parietal eye. They were often observed to be active by night and often slept outside a burrow. The circadian rhythm of V. b. nebulosus appeared unaffected by shielding of its parietal eye. Captivity combined with shielded parietal eye induced agonistic behaviour in both species. Accepted: 11 September 1996     

Activity patterns of the serotine bat (Eptesicus serotinus) at a roost in southern England

Activity patterns and emergence times of a colony of serotine bats, Eptesicus serotinus , were studied in southern England. Time of emergence from the day roost varied over the summer but was strongly correlated with sunset. Mean emergence time was 11.6 ± 7.7 min after sunset. Early in summer, activity patterns were unimodal, becoming bimodal during mid- to late pregnancy and multimodal in early to mid-lactation. When juveniles were volant, activity patterns became unimodal again. Periods of low ambient temperature were associated with reduced activity. The duration of the first foraging flight decreased as pregnancy progressed, possibly as a result of the greater wing-loading caused by increased body mass. However, the first foraging flight increased in duration during the course of lactation, probably in response to a combination of increased night length and the increased energetic demands of milk production. It is concluded that seasonal variation in the length of time spent away from the roost in the serotine is related to reproductive status, night length and ambient temperature. It is suggested that the more northerly distribution of this bat in continental Europe may be due to differences in habitat use and diet.     

Activity patterns of pipistrelle bats (Pipistrellus pipistrellus) in Oxfordshire

A maternity colony of pipistrelle bats ( Pipisfrellus pipistrellus ), in Oxfordshire, was monitored between 1 March 1989 and 6 October 1989. An infra-red 'automatic bat counter' was installed at the roost, to record the number of bats entering and leaving each minute throughout the night. Air temperature, light intensity at sunset, cloud cover, wind speed and rain were recorded on each night of monitoring. Insect abundance was estimated on 18 nights.
The nightly activity pattern was found to be unimodal in pregnancy, bimodal during lactation and unimodal post-weaning. The mean time that each bat spent outside the roost ranged from 103–483 min, with a mean of 321 min.
Ambient air temperature and length of night were significant factors affecting mean time spent outside the roost. The percentage of the night which the bats spent away from the roost ranged from 22 to 88%, with a mean of 64%. There was a significant positive correlation between ambient air temperature and percentage of the night spent away from the roost. Insect abundance showed no significant correlation with the time that bats spent outside the roost. Wind and rain had no apparent effect on time spent outside the roost.     

Alteration in diel activity patterns as a thermoregulatory strategy in black wildebeest (<Emphasis Type="Italic">Connochaetes gnou</Emphasis>)

The nychthemeral activity patterns of a population of female black wildebeest inhabiting a shadeless environment were surveyed periodically over 1 year. The wildebeest fed mostly at night, with the proportion of feeding at night increasing when ambient conditions were hotter. Inactive periods were spent mostly lying during cooler weather but standing as days became hotter. We suggest that the entire suite of behavioural adjustments is beneficial to heat exchange with the environment. Behaviour patterns were markedly different during one warm weather survey, from the other warm weather surveys, when an 8-month dry spell had just been broken. We suggest that this may reflect the availability of water for autonomic thermoregulation, a consequent decreased reliance on behavioural thermoregulation, and a release of the thermal constraints on foraging. Our results help to explain the ability of black wildebeest to maintain body core temperature within a very narrow range despite being exposed to an environment with large nychthemeral variations in thermal conditions and offering little in the way of microclimate selection.