Changes in body size in fluctuating populations of the collared lemming: age and photoperiod influences

1981 ◽  
Vol 59 (2) ◽  
pp. 174-182 ◽  
Author(s):  
Frank F. Mallory ◽  
J. Richard Elliott ◽  
Ronald J. Brooks

Paired wet lens weights of 115 laboratory-reared collared lemmings were plotted against known age, to assess the reliability of this parameter, as a means of estimating age. Approximately 85% of the total variability in In age (A) was accounted for by In paired wet lens weight (W) (equation of best fit; In A (days) = −0.9771 + 2.186 In W (milligrams). In addition, variation in gender and photoperiod did not influence lens weight, although other parameters such as body weight and pelage were significantly affected.Field data from Eskimo Point, N. W.T., indicated that animals were older and heavier during the peak year (1973). Reduced recruitment and length of breeding season were observed during high densities, and sexual maturation was delayed in the nonbreeding segment of the population. Fluctuations in body size during microtine cycles were discussed as influenced by age, photoperiod, and shifts in the breeding season.

1961 ◽  
Vol 22 (4) ◽  
pp. 387-393 ◽  
Author(s):  
HELEN CHITTY

SUMMARY 1. Mean weights are given for the adrenal glands of 1167 male and 806 female voles from naturally fluctuating populations at Lake Vyrnwy, Wales, during 1952–58. 2. Although the mean standardized adrenal weights of both males and females varied from year to year, no consistent relationship with population trend could be found, except that females from expanding populations tended to have the heaviest adrenals. 3. The adrenal weights increased seasonally each year from low values in the spring to maxima in midsummer and decreased again to low values in the autumn. 4. This fluctuation was exhibited not only by breeding animals but also by those that were sexually immature. It therefore seems unlikely that the seasonal enlargement is entirely a direct effect of gonadal activity, though it may be due to changes in social behaviour during the breeding season. 5. In each month the adrenals of pregnant or lactating females were heavier than those of nulliparous animals of the same body weight.


2020 ◽  
Vol 3 (2(71)) ◽  
pp. 22-28
Author(s):  
N.I. Fulga ◽  
I.K. Toderash ◽  
D.E. Bulat ◽  
D.E. Bulat

The results of studies of the reproductive system of sexually mature females of the round goby Neogobius melanostomus (Pallas, 1814) from the Lower Dniester during the spawning season are presented. The age of sexual maturation and the timing of spawning of fish in the conditions of this basin are determined. Asynchrony in the development of germ cells has been identified, which provides four-time spawning during the entire breeding season of fish. Throughout the entire reproductive cycle, larger females with greater body weight and gonad mass are the first to spawn.


2011 ◽  
Vol 286 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Eva Küttner ◽  
Hooman K. Moghadam ◽  
Skúli Skúlason ◽  
Roy G. Danzmann ◽  
Moira M. Ferguson

Herpetologica ◽  
10.1655/03-97 ◽  
2004 ◽  
Vol 60 (4) ◽  
pp. 414-419 ◽  
Author(s):  
Narahari P. Gramapurohit ◽  
Bhagyashri A. Shanbhag ◽  
Srinivas K. Saidapur

1971 ◽  
Vol 55 (3) ◽  
pp. 651-665 ◽  
Author(s):  
G. M. HUGHES ◽  
R. GAYMER ◽  
MARGARET MOORE ◽  
A. J. WOAKES

1. The O2 consumption and CO2 release of nine giant tortoises Testudo gigantea (weight range 118 g-35·5 kg) were measured at a temperature of about 25·5°C. Four European tortoises Testudo hermanni (weight range 640 g-2·16 kg) were also used. The mean RQ values obtained were 1·01 for T. gigantea and 0·97 for T. hermanni. These values were not influenced by activity or size. 2. The data was analysed by plotting log/log regression lines relating body weight to O2 consumption. Both maximum and minimum metabolic rates recorded for each individual T. gigantea showed a negative correlation with body weight. For active rates the relation was O2 consumption = 140·8W0·97, whereas for inactive animals O2 consumption = 45·47W0·82. 3. The maximum rates were obtained from animals that were observed to be active in the respirometer and the minimum rates from animals that remained quiet throughout. The scope for activity increased with body size, being 82 ml/kg/h for animals of 100 g and 103 ml/kg/h for 100 kg animals. The corresponding ratio between maximum and minimum rates increases from about 2 to 6 for the same weight range. 4. Values for metabolic rate in T. hermanni seem to be rather lower than in T. gigantea. Analysis of the relative proportion of the shell and other organs indicates that the shell forms about 31% of the body weight in adult T. hermanni but only about 18% in T. gigantea of similar size. The shell is not appreciably heavier in adult T. gigantea (about 20%). 5. Data obtained for inactive animals is in good agreement with results of other workers using lizards and snakes. Previous evidence suggesting that chelonians show no reduction in metabolic rate with increasing size is not considered to conflict with data obtained in the present work.


1994 ◽  
Vol 76 (1) ◽  
pp. 314-320 ◽  
Author(s):  
C. L. Marcus ◽  
W. B. Glomb ◽  
D. J. Basinski ◽  
S. L. Davidson ◽  
T. G. Keens

The developmental pattern of ventilatory responses, through childhood and puberty into adulthood, is not known. Therefore we studied hypercapnic (HCVR) and hypoxic ventilatory responses (HOVR) in 59 subjects (29 males and 30 females) 4–49 yr of age, of whom 35 were children ( < 18 yr old). There was a significant correlation between HCVR and weight (r = 0.33, P < 0.02), vital capacity (r = 0.30, P < 0.05), and body surface area (r = 0.30, P < 0.05) but not height (r = 0.22, NS). There was no correlation between HOVR and any of the correcting factors. To account for disparities in body size, volume-related results were scaled for body weight. The HCVR corrected for weight (HCVR/WT) decreased with age (r = -0.57, P < 0.001). HCVR/WT was significantly higher in children than in adults (0.056 +/- 0.024 vs. 0.032 +/- 0.015 l.kg-1 x min-1. Torr end-tidal PCO2-1, P < 0.001). The (tidal volume/inspiratory duration)/weight, respiratory rate, and heart rate responses to hypercapnia were increased in the children, and the CO2 threshold was lower (36 +/- 5 vs. 40 +/- 6 Torr, P < 0.05). Similarly, the HOVR corrected for weight (HOVR/WT) decreased with age (r = 0.34, P < 0.05), and HOVR/WT was significantly higher in children than in adults (-0.035 +/- 0.017 vs. -0.024 +/- 0.016 l.kg-1 x min-1.% arterial O2 saturation-1, P < 0.02). The respiratory rate and heart rate responses to hypoxia were increased in the children. We conclude that rebreathing HCVR and HOVR are higher during childhood than during adulthood.


1988 ◽  
Vol 3 (3) ◽  
pp. 193-196 ◽  
Author(s):  
S. Barni ◽  
P. Lissoni ◽  
S. Crispino ◽  
F. Rovelli ◽  
G. Esposti ◽  
...  

Melatonin secretion is often enhanced in patients with cancer. In the light of a reported correlation between melatonin levels and body size, we investigated blood levels of this pineal hormone in a group of 72 patients affected by cancer, 30 of whom had body weight within the normal range, 30 were obese and the last 12 cases had body weight below the normal range, in order to establish whether in fact melatonin blood concentrations were related to body size. Melatonin levels were high in 19/72 patients (26%). The mean levels of the pineal hormone were similar in patients with normal, low and high body weight. Finally, there was no significant correlation between melatonin values and body weight, height or surface. Melatonin secretion thus does not appear to be influenced by body size in cancer patients.


2019 ◽  
Vol 17 (1) ◽  
pp. e0601
Author(s):  
Alicia Román-Trufero ◽  
Antonio Martínez ◽  
Luis M. M. Ferreira ◽  
Valentín García-Prieto ◽  
Rocío Rosa-García ◽  
...  

Steer meat production in northern Spain is deficient to attend market demand. This research aimed to compare the foraging behaviour and production of yearling steers from two local breeds differing in body weight (BW), Asturian Valley (AV, 372 kg) and Asturian Mountain (AM, 307 kg), grazing in summer pastures consisting of 70% grassland and 30% heathland. Bodyweight gains from a total of 42 steers were recorded during four grazing seasons (from June to October). In two years, in July and September, plant community selection and diet composition were estimated by direct observation and using faecal markers, respectively. Grazing time increased from July to September (488 vs. 557 min/day; p<0.001) as sward height in the grassland decreased. Although AV steers grazed proportionally for longer on herbaceous pastures than AM steers (81.3 vs. 73.3%; p<0.05), no differences between breeds were found in diet composition. AM steers showed greater mean daily BW gains than AV steers (252 vs. 133 g/day; p<0.01). From June to August, steers from both breeds gained BW (487 vs. 360 g/day for AM and AV, respectively; p<0.01), but thereafter BW gains decreased (120 vs. –12 g/day for AM and AV, respectively; p<0.05), because of reduced availability of grassland herbage. Yearling steers from AM breed seem to be better suited to mountain conditions than those from AV breed, probably because of their smaller body size and lower total nutrient requirements for maintenance.


Author(s):  
P. M. Parés- Casanova ◽  
A. Kabir

Sexual dimorphism, defined as phenotypic differences between males and females, is a common phenomenon in animals. In this line, Rensch’s rule states that sexual size dimorphism increases with increasing body size when the male is the larger sex and decreases with increasing average body size when the female is the larger sex. Domesticated animals offer excellent opportunities for testing predictions of functional explanations of Rensch’s theory. Pigeon breeds encounters many different functional purposes and selective constraints, which could influence strongly their morphology. The aim of this paper is to examine, for first time, Rensch’s rule among domestic pigeons. It was compiled a database of 12 quantitative traits (body weight, body height, beak thickness, beak length, neck length, neck thickness, wing length, rump width, tail length, tarsus length, tarsus thickness and middle toe length) for males and females of 11 different domestic pigeon breeds: Bangladesh Indigenous, Racing Homer, Turkish Tumbler, Indian Lotan, Kokah, Mookee, Indian Fantail, Bokhara Trumpeter, Bombai, Lahore and Hungarian Giant House; Rock Pigeon (Columba livia) was also considered as wild relative for comparative purposes. Comparative results between males and females showed that only body weight, wing length and neck thickness were consistent with Rensch’s rule. The rest of trait did not present correlations. Among domestic pigeons, there can appear different expressions of dimorphism according to each trait, so it must be considered that Rensch’s rule vary when considering other traits than body weight.


2020 ◽  
Author(s):  
Yu_an Zhang ◽  
Zijie Sun ◽  
Chen Zhang ◽  
Shujun Yin ◽  
Wenzhi Wang ◽  
...  

Abstract In stock farming, the body size parameters and weight of yaks can reasonably reflect the growth and development characteristics, production performance and genetic characteristics of yaks. However, it is difficult for herders to measure the body size and weight of yaks by traditional manual methods. Fortunately, with the development of edge computing, herders can use mobile devices to estimate the yak’s body size and weight. The purpose of this paper is to provide a machine vision-based yak weight estimation method for the edge equipment and establish a yak estimation comprehensive display system based on the user’s use of the edge equipment in order to maximize the convenience of herdsmen’s work. In our method, a set of yak image foreground extraction and measurement point recognition algorithm suitable for edge equipment were developed to obtain yak’s measurement point recognition image, and the ratio between body sizes was transmitted to the cloud server. Then, the body size and weight of yaks were estimated using the data mining method, and the body size estimation data were constantly displayed in the yak estimation comprehensive display system. 25 yaks in different age groups were randomly selected from the herd to perform experiments. The experimental results show that the foreground extraction method can obtain segmentation image with good boundary, and the yak measurement point recognition algorithm has good accuracy and stability. The average error between the estimated values and the actual measured values of body height, oblique length, chest depth, cross height and body weight is 1.95%, 3.11%, 4.91%, 3.35% and 7.79%, respectively. Compared with the traditional manual measurement method, the use of mobile end to estimate the body size and weight of yaks can improve the measurement efficiency, facilitate the herdsmen to breed yaks, reduce the stimulation of manual measurement on yaks, and lay a solid foundation for the fine breeding of yaks in Sanjiangyuan region.


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