Seasonal changes in aggression, hunger, and curiosity in ranch mink

1969 ◽  
Vol 47 (6) ◽  
pp. 1395-1404 ◽  
Author(s):  
R. R. MacLennan ◽  
E. D. Bailey
Keyword(s):  
Breeding Season ◽  
Seasonal Changes ◽  
Environmental Temperature ◽  
Gonadal Hormones ◽  
Corpora Lutea ◽  
Field Situation ◽  
Body Weights ◽  
Males And Females ◽  
And Storage ◽  
Ranch Mink

Aggression, hunger, and curiosity of ranch mink (Mustela vison) were examined. The animals were divided into socialized animals (those visually isolated at 1 year of age) and unsocialized animals (those visually isolated at 10 weeks of age).Aggression was measured by placing two mink in a special cage and measuring the time until a fight or confrontation occurred. The effects of 0, 24, and 48 hours of food deprivation were measured in summer, fall, and winter. The number of trips made by each mink up a vertical cage to get food was used as an indicator of hunger. Levels of curiosity were determined by measuring the speed and pattern of exploration of a novel open-field situation. The breeding behaviors of experienced and inexperienced male mink were compared.Aggression in mink consisted of at least two offensive threats and, as in other animals, fighting was ritualized to a great extent. All young mink showed some adult aggressive patterns by 20 weeks of age. Aggression in males reached a peak at breeding season (March) and declined throughout the summer and fall, to a low point in November. Socialized males had lower aggressive levels than unsocialized males. Aggression in female mink reached a peak after the breeding season and declined to a low in winter. These cycles were likely caused by gonadal hormones in males and hormones from the corpora lutea in females.Both consumption and storage of food must be considered in determining hunger in mink. Hunger varied inversely with environmental temperature, reaching a peak in the winter and a low point in the summer. Immature animals had lower hunger drives than adult animals. Changes in body weights of mink centered around the breeding season.Curiosity decreased from summer to fall as did aggression. Unsocialized males had higher levels of curiosity than socialized males and females. Immature mink showed incomplete exploratory behavior and had lower curiosity scores than adult animals.

Odor preference and social behavior in meadow voles, Microtus pennsylvanicus: seasonal differences

1987 ◽  
Vol 65 (12) ◽  
pp. 2931-2937 ◽  
Author(s):  
Michael H. Ferkin ◽  
Joshua O. Seamon
Keyword(s):  
Social Behavior ◽  
Social Organization ◽  
Breeding Season ◽  
Seasonal Changes ◽  
Microtus Pennsylvanicus ◽  
Odor Preference ◽  
Nonbreeding Season ◽  
Y Maze ◽  
Female Territoriality ◽  
Males And Females

Olfactory cues play a major role in inter- and intra-sexual agonistic behavior for Microtus pennsylvanicus. We show that seasonal changes in odor preference and behavioral interactions coincide with varying patterns of social organization. Odor preference trials were conducted in a Y maze and social behavior was measured in dyadic encounters in a neutral arena. During the breeding season, paired encounters between females contained more agonistic acts than did encounters between males, or those between males and females. Breeding males preferred the odor of females to the odor of conspecific males. In contrast, breeding females preferred their own odor and the odor of males to the odor of other females. The data support female exclusiveness during the breeding season. During the nonbreeding season, paired encounters between females contained fewer agonistic acts than did encounters between males or those between males and females. Nonbreeding females preferred the odor of female conspecifics to their own odor or the odor of male conspecifics. These results are consistent with group nesting and a relaxation of female territoriality during the nonbreeding season. Nonbreeding males did not exhibit a preference for their own odor, the odor of other males, or the odor of female conspecifics. Our results indicate that nonbreeding males are solitary, and overwintering groups are female-biased. Odor preferences may underlie seasonal changes in social organization.

scholarly journals Reproduction in the common shrew ( Sorex araneus Linnæus ). II—Seasonal changes in the reproductive organs of the male

1935 ◽  
Vol 225 (518) ◽  
pp. 51-62 ◽  
Keyword(s):  
Breeding Season ◽  
Seasonal Changes ◽  
Common Shrew ◽  
Reproductive Organs ◽  
Sorex Araneus ◽  
The Body ◽  
Body Weights ◽  
The Common ◽  
Common Shrew Sorex Araneus ◽  
Male Reproductive Organs

The male Common Shrews obtained at the same time and in the same way as the females provide material which throws further light on the duration of life and of the breeding season in this species. This paper deals with the body-weights, weights of the reproductive organs and the occurrence of spermatozoa in the testes. The duration of fertility in the male and in the female are compared. The anatomy of the male reproductive organs is described by Ärnbäck-Christie-Linde (1907) and requires only brief consideration here.

Observation on the breeding biology of Polypedates teraiensis (Dubois, 1987) (Amphibia: Rhacophoridae)

2017 ◽  
Vol 17 (1) ◽  
pp. 25-32
Author(s):  
Jacinta Lalchhanhimi ◽  
Lalremsanga H.T.
Keyword(s):  
Sexual Dimorphism ◽  
Breeding Season ◽  
Sound Production ◽  
Reproductive Function ◽  
Breeding Biology ◽  
Tree Frog ◽  
University Campus ◽  
Morphometric Measurements ◽  
Advertisement Calls ◽  
Males And Females

The breeding biology of tree frog, Polypedates teraiensis was studied during the breeding season at Mizoram University Campus. It was found that sound production by male during the breeding season was primarily a reproductive function and advertisement calls attract females to the breeding areas and announce other males that a given territory is occupied. The aim of this study was to provide the detailed information on the breeding behaviour and the advertisement calls of Polypedates teraiensis. The morphometric measurements of the amplecting pairs (males and females) for sexual dimorphism along with clutch sizes were also studied.

scholarly journals Evidence for use of both capital and income breeding strategies in the mangrove tree crab, Aratus pisonii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jade Carver ◽  
Morgan Meidell ◽  
Zachary J. Cannizzo ◽  
Blaine D. Griffen
Keyword(s):  
Breeding Season ◽  
Breeding Strategy ◽  
Reproductive Period ◽  
Breeding Strategies ◽  
Mangrove Tree ◽  
Income Breeding ◽  
Aratus Pisonii ◽  
Breeding Seasons ◽  
And Storage ◽  
Capital And Income Breeding

AbstractTwo common strategies organisms use to finance reproduction are capital breeding (using energy stored prior to reproduction) and income breeding (using energy gathered during the reproductive period). Understanding which of these two strategies a species uses can help in predicting its population dynamics and how it will respond to environmental change. Brachyuran crabs have historically been considered capital breeders as a group, but recent evidence has challenged this assumption. Here, we focus on the mangrove tree crab, Aratus pisonii, and examine its breeding strategy on the Atlantic Florida coast. We collected crabs during and after their breeding season (March–October) and dissected them to discern how energy was stored and utilized for reproduction. We found patterns of reproduction and energy storage that are consistent with both the use of stored energy (capital) and energy acquired (income) during the breeding season. We also found that energy acquisition and storage patterns that supported reproduction were influenced by unequal tidal patterns associated with the syzygy tide inequality cycle. Contrary to previous assumptions for crabs, we suggest that species of crab that produce multiple clutches of eggs during long breeding seasons (many tropical and subtropical species) may commonly use income breeding strategies.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).

The effect of stage of breeding season or pre-mating oestrogen and progestagen therapy on fertility in ewe lambs

1994 ◽  
Vol 59 (3) ◽  
pp. 429-434 ◽  
Author(s):  
N. F. G. Beck ◽  
M. C. G. Davies
Keyword(s):  
Breeding Season ◽  
Corpora Lutea ◽  
Oestrogen Therapy ◽  
Crown Rump Length ◽  
Ewe Lambs ◽  
Oestradiol Benzoate

AbstractAn investigation was conducted to determine the effect of mating at puberty or third oestrus or after pre-mating oestrogen and progestagen therapy, designed to mimic the changes that occur in plasma oestrogen and progesterone concentrations during the 1st, 2nd or 3rd oestrous cycles, on fertility in ewe lambs. Twenty-five ewe lambs were mated at puberty on mean date of 18 October and 21 were mated at third oestrus on 3 December. Of these, 28% and 81% of animals mated at puberty and third oestrus lambed, respectively (P < 0·05). A similar number of ewe lambs were mated within 24 h of ram introduction in the groups given one, two or three consecutive applications oestrogen and progestagen (25 μg oestradiol benzoate followed 48 h later by a progestagen pessary left in situ for days). Of the 43 corpora lutea, 21 were represented by viable embryos in the 37 animals holding to service after one application compared with 34 out of 46 corpora lutea in 40 animals given three applications (P < 0·05). Furthermore, embryo crown-rump length, embryo weight and amniotic sac width was greater (P < 0·05), on day of pregnancy, in animals given one compared with three applications of oestrogen and progestagen. These results demonstrate that fertility is improved in ewe lambs mated on third oestrus or after progestagen and oestrogen therapy designed to simulate three oestrous cycles.

scholarly journals Immunotoxicity of Per- and Polyfluoroalkyl Substances: Insights into Short-Chain PFAS Exposure

Toxics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 100
Author(s):  
Tracey Woodlief ◽  
Samuel Vance ◽  
Qing Hu ◽  
Jamie DeWitt
Keyword(s):  
Drinking Water ◽  
Nk Cell ◽  
Positive Control ◽  
Oral Exposure ◽  
Body Weights ◽  
Toxicological Data ◽  
Males And Females ◽  
Polyfluoroalkyl Substances ◽  
Compound Exposure ◽  
Control Terminal

Novel per- and polyfluoroalkyl substances (PFAS) were recently identified in drinking water sources throughout North Carolina. These include the perfluoroether acids (PFEAs) perfluoro-2-methoxyacetic acid (PFMOAA), perfluoro-2-methoxypropanoic acid (PFMOPrA), and perfluoro-4-methoxybutanioc acid (PFMOBA). Little toxicological data exist for these PFEAs. Therefore, the present study described signs of toxicity and immunotoxicity following oral exposure. Adult male and female C57BL/6 mice were exposed once/day for 30 days to PFMOAA (0, 0.00025, 0.025, or 2.5 mg/kg), PFMOPrA, or PFMOBA (0, 0.5, 5, or 50 mg/kg). A dose of 7.5 mg/kg of perfluorooctanoic acid (PFOA) was used as a positive control. Terminal body weights, and absolute liver, spleen, or thymus weights did not differ by dose for any compound; exposure to 50 mg/kg of PFMOBA increased relative liver weights in males. Changes in splenic cellularity were observed in males exposed to PFMOPrA and decreased numbers of B and natural killer (NK) cells were observed in males and females exposed to PFMOBA. Exposure did not alter NK cell cytotoxicity or T cell-dependent antibody responses at doses administered. Our results indicate that these “understudied” PFAS have toxicological potential but require additional investigation across endpoints and species, including humans, to understand health effects via drinking water exposure.

GONADAL HORMONES AND THE CONTROL OF OVULATION IN THE GUINEA-PIG

1972 ◽  
Vol 55 (3) ◽  
pp. 599-607 ◽  
Author(s):  
B. T. DONOVAN ◽  
A. N. LOCKHART
Keyword(s):  
Guinea Pig ◽  
Corpus Luteum ◽  
Acute Treatment ◽  
Gonadal Hormones ◽  
Time Of Day ◽  
Gonadal Steroids ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate

SUMMARY The release of ovulating hormone after acute treatment with gonadal steroids, or corpus luteum removal on different days of the oestrous cycle, was studied in the guinea-pig. Injection of 25, 50 or 100 μg oestradiol or 2·5 mg progesterone on day 13 of the cycle had no effect upon gonadotrophin secretion as judged by follicular histology, but markedly altered the sizes of the corpora lutea of the previous ovulation. Treatment with oestradiol on day 14 did not elicit gonadotrophin secretion. However, administration of the same hormones to animals given 10 μg oestradiol benzoate 24 h earlier caused ovulation or follicular luteinization. Progesterone (2·5 mg) appeared least effective in stimulating gonadotrophin release; 25 μg oestradiol were more effective when given at 12.00 h than at 24.00 h but treatment with both hormones caused ovulation when given at either time of day. Luteal volumes were not affected. Removal of corpora lutea during the second half of the cycle advanced the time of expected ovulation to day 15 or earlier when the procedure was carried out on days 8 or 9, but not on days 10–13. It is concluded that 4–5 days must elapse between the fall in plasma progesterone level associated with corpus luteum regression and the release of ovulating hormone.

The effect of melatonin treatment during the seasonal anoestrus on the superovulatory response and embryo production of high-prolificacy Rasa Aragonesa ewes before culling

2003 ◽  
Vol 2003 ◽  
pp. 82-82
Author(s):  
F. Forcada ◽  
J.A. Abecia ◽  
J.A. Valares
Keyword(s):  
Embryonic Development ◽  
Breeding Season ◽  
Litter Size ◽  
Direct Effect ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Melatonin Treatment ◽  
Embryo Production ◽  
Spring Equinox

The efficacy of melatonin implants inserted around the spring equinox to improve fertility and ovulation rate or litter size in Mediterranean ewes has been previously reported (Chemineau et al., 1996; Forcada et al., 2002a.), indicating the ability of the hormone to regulate the hypothalamic activity (Viguié et al., 1995). Moreover, a direct effect of melatonin on corpora lutea and embryonic development has been also reported (Wallace et al., 1988; Abecia et al., 2002). The use of prolific Rasa Aragonesa (RA) ewes (a Mediterranean breed) before culling as embryo donors has been previously tested in the breeding season (Forcada et al., 2002b.). The aim of this experiment was to improve embryo production during the seasonal anoestrus period in selected superovulated RA ewes at the end of their reproductive lives through the use of melatonin.

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