Short-term association patterns of humpback whale (Megaptera novaeangliae) groups on their feeding grounds in the southern Gulf of Maine

1991 ◽  
Vol 69 (12) ◽  
pp. 3005-3011 ◽  
Author(s):  
Mason T. Weinrich ◽  
Anne E. Kuhlberg
Keyword(s):  
Group Size ◽  
Adult Female ◽  
Adult Male ◽  
Gulf Of Maine ◽  
Humpback Whale ◽  
Distinct Pattern ◽  
Megaptera Novaeangliae ◽  
Adult Males ◽  
Feeding Ground ◽  
Social Nature

Humpback whale (Megaptera novaeangliae) feeding ground associations show a distinct pattern of group size and composition. Median group size was 2 (mean 1.67), and frequency decreased as group size increased. Adult females and juvenile males were observed in pairs significantly more often than singly, whereas adult males and juvenile females were more often alone. Adult female–female pairs occurred significantly more frequently than adult male–male pairs, and adult female – juvenile male pairs formed more frequently than adult male – juvenile female pairs. The majority of groups remained associated for at least 10 min; however, as the size of a group increased, so did its tendency to separate within that period. Adult male–male pair associations were of significantly shorter duration than female–female or male–female pair associations. It is hypothesized that adult males may avoid other males on the feeding ground as an extension of breeding competition. The energetic burden of reproduction, and hence the need to forage cooperatively to maximize efficiency, may account for the adult female's social nature. Juveniles of both sexes, less constrained by reproductive costs, exhibit less structured social behavior.

The relationship of social vocalizations to surface behavior and aggression in the Hawaiian humpback whale (Megaptera novaeangliae)

1986 ◽  
Vol 64 (10) ◽  
pp. 2075-2080 ◽  
Author(s):  
Gregory K. Silber
Keyword(s):  
Surface Activity ◽  
Group Size ◽  
Social Dominance ◽  
Humpback Whale ◽  
Megaptera Novaeangliae ◽  
Adult Males ◽  
Surface Behavior ◽  
Relationship Of ◽  
Large Groups ◽  
The Relationship

Humpback whale (Megaptera novaeangliae) social vocalizations (nonsong sounds) were clearly related to whale group size and surface activity. Social sounds occurred almost exclusively in groups containing three or more whales and were rarely heard near single whales, pairs, or cow–calf groups. Large groups (3 to 20 individuals) vocalized at an overall mean rate of 43.1 ± 55.52 sounds per whale/h. Group size changed frequently and a dramatic increase in vocalization rate resulted when a new whale entered a group. Large groups engaged in flurries of surface activity, such as breaching, flipper- and tail-slapping, and underwater bubbling. Aggressive encounters resulted from male–male interaction. Social sounds probably acted to demonstrate aggression or agitation as adult males competed for temporary social dominance within the group and for proximity to the female. Likewise, visual displays may have been used as threats in close quarters and were apparently produced in conjunction with sounds to convey levels of aggression. Although other studies suggested that surface activity increased with group size, I found a negative correlation between activity and group size, both in the group as a whole and per individual. In contrast, social vocalizations per group increased with group size while the vocalization rate per individual did not vary significantly with increasing group size.

Effects of adults on survival and recruitment of Peromyscus leucopus

1987 ◽  
Vol 65 (10) ◽  
pp. 2519-2523
Author(s):  
Gregory H. Adler ◽  
Mark L. Wilson ◽  
Michael J. DeRosa
Keyword(s):  
Adult Female ◽  
Adult Male ◽  
Peromyscus Leucopus ◽  
Survival Rates ◽  
Adult Males ◽  
Control Grid ◽  
Young Males ◽  
Young Females ◽  
Breeding Seasons ◽  
And Control

A population of Peromyscus leucopus (white-footed mouse) in northeastern Massachusetts was manipulated for 3 years to determine the effects of adults on survival and recruitment. Two experimental grids were established, from which either all adult males or all adult females were removed continually. The effects of these two manipulations were compared with demography on a control grid. Manipulations had no apparent effect on breeding intensity of young, survival rates of adults, or residency rates of adults and young. Recruitment of adult males was higher on the adult male removal grid than on the control grid. Recruitment rates of adult males and of young males and young females were lower on the adult female removal grid than on the control grid. Survival rates of young males were higher on the adult female removal grid than on the control grid; this effect may have been due to either reduced adult female residency or adult male recruitment. All differences between experimental and control grids were noted only during breeding seasons. Adult males apparently limited recruitment of adult consexuals. The effects of manipulations on other measured parameters were inconclusive because of high immigration rates of adult males onto the adult male removal grid and reduced recruitment of adult males and decreased production of young on the adult female removal grid.

ADRENAL WEIGHT IN WILD MALLARD AND DOMESTIC DUCKS AND SEASONAL ADRENAL WEIGHT CHANGES IN THE MALLARD

1965 ◽  
Vol 43 (3) ◽  
pp. 475-487 ◽  
Author(s):  
E. O. Höhn ◽  
A. K. Sarkar ◽  
A. Dzubin
Keyword(s):  
Sex Differences ◽  
Breeding Season ◽  
Adult Female ◽  
Adult Male ◽  
Adrenal Weight ◽  
Adult Males ◽  
Weight Changes ◽  
Domestic Ducks ◽  
Testicular Weight ◽  
Wild Mallard

Mallards and domestic ducks are conspecific. Relative adrenal weight is similar in newly hatched mallards and domestic ducks. Immature mallards have higher relative adrenal weights than domestic ducks of similar age. Adult female mallards also have higher relative adrenal weights and a higher proportion of cortex in the adrenal than adult female domestic ducks, but adult males of the two strains fail to show these differences.Adrenal weight is related to testicular weight in mallards and domestic ducks, but no correlation is evident between adrenal weight and weight of the ovary and oviduct in mallards. Mallards show no adrenal weight sex differences at any of the three ages sampled. A seasonal adrenal weight cycle is apparent in both sexes of the mallard with a weight increase related to the breeding season and another increase during the autumn and winter.The higher relative adrenal weights of (immature and adult female) mallards compared to those of domestic ducks are attributed to the mallards' greater exposure to stress. It is suggested that this effect operates also in adult male mallards but is obscured in the comparison with adult male domestic ducks because in the latter, which have much higher testicular weights, another factor responsible for the correlation between adrenal and testicular weight as noted above makes for increased adrenal weights.

EFFECT OF SEX AND AGE AT GONADECTOMY ON THE SEBACEOUS RESPONSE TO PROGESTERONE

1977 ◽  
Vol 73 (1) ◽  
pp. 67-70 ◽  
Author(s):  
SAM SHUSTER ◽  
WENDY M. HINKS ◽  
A. J. THODY
Keyword(s):  
Adult Female ◽  
Adult Male ◽  
Female Rats ◽  
Male Rats ◽  
Adult Males ◽  
Adult Rat ◽  
Sebum Production ◽  
Males And Females ◽  
Sebum Secretion

SUMMARY The effect of progesterone on the rate of sebum secretion was examined in intact and gonadectomized rats. In intact, adult, male rats, progesterone administered for 3 weeks decreased sebum secretion; after castration of adult males, progesterone increased sebum secretion and an even greater response occurred in males castrated at 21 days of age. In intact, adult, female rats progesterone slightly increased sebum production. As in the male, the response was affected by the time of gonadectomy, a greater response occurring after spaying at 21 days compared with 10 weeks of age. Thus, the response to progesterone in the adult rat differs in intact males and females and is affected by changes in the endocrine environment induced by gonadectomy, especially near the time of puberty.

scholarly journals Population status and distribution of Rhesus Macaque, Macaca mulatta, in a moist deciduous forest of Bangladesh

2016 ◽  
Vol 44 (1) ◽  
pp. 60-72
Author(s):  
Habibon Naher ◽  
Shawkat Imam Khan ◽  
Tanvir Ahmed
Keyword(s):  
Sex Ratio ◽  
Rhesus Macaque ◽  
Group Size ◽  
Adult Female ◽  
Adult Male ◽  
Macaca Mulatta ◽  
Total Population ◽  
Deciduous Forest ◽  
Population Status ◽  
Male And Female

A study was conducted on population status and distribution of Rhesus Macaque, Macaca mulatta, in moist deciduous forest of Bangladesh from April to October 2015. Observation was carried out in the Madhupur deciduous forest, Tangail. In total, 248 individuals belonging to 11 groups were recorded. The group size ranged from 9 to 51 (mean 22.54 ± 11.68) individuals. Among the total population, 48.5% were adults and 51.5% immature animals (sub-adult male, sub-adult female, juvenile and infant). The ratio of adult and immature was 1 : 1.85 and the sex ratio of adult male and female was 1 : 1.49. The groups were 0.77 to 7.47 km (mean 2.5 km ± 2.2, n = 11) apart from each other.Bangladesh J. Zool. 44(1): 61-72, 2016

The impact of entanglements on two substocks of the western North Atlantic humpback whale, Megaptera novaeangliae

1995 ◽  
Vol 73 (9) ◽  
pp. 1689-1698 ◽  
Author(s):  
Lisa Volgenau ◽  
Scott D. Kraus ◽  
Jon Lien
Keyword(s):  
North Atlantic ◽  
Newfoundland And Labrador ◽  
Birth Rate ◽  
Gulf Of Maine ◽  
Humpback Whale ◽  
Megaptera Novaeangliae ◽  
Fishing Gear ◽  
The Impact ◽  
Annual Mortality ◽  
Mortality Estimates

Increased use of fishing gear in the marine environment can be detrimental to animals such as cetaceans, particularly through entanglement. Examination of the impact of such mortality on two substocks of the western North Atlantic humpback whale, Megaptera novaeangliae, indicates that when entanglement losses are added to natural mortality estimates and subtracted from birth rate estimates, annual mortality may be as high as 5.4% in the Newfoundland and Labrador population and 4.8% in the Gulf of Maine population. More effective entanglement reporting and assisting systems are needed in the Gulf of Maine and increased efforts are needed to decrease entanglements, entanglement mortalities, and damages to fishing gear. We conclude that monitoring of the size of humpback populations needs to continue, given their particular vulnerability to coastal fishing and the potential impacts of entanglement mortality.

Humpback whale (Megaptera novaeangliae) song unit and phrase repertoire progression on a subarctic feeding ground

2015 ◽  
Vol 138 (5) ◽  
pp. 3362-3374 ◽  
Author(s):  
Edda E. Magnúsdóttir ◽  
Patrick J. O. Miller ◽  
Rangyn Lim ◽  
Marianne H. Rasmussen ◽  
Marc O. Lammers ◽  
...  
Keyword(s):  
Humpback Whale ◽  
Megaptera Novaeangliae ◽  
Feeding Ground

Mane variation in African lions and its social correlates

2002 ◽  
Vol 80 (3) ◽  
pp. 471-478 ◽  
Author(s):  
Roland W Kays ◽  
Bruce D Patterson
Keyword(s):  
Group Size ◽  
Adult Male ◽  
National Park ◽  
Social Groups ◽  
Future Research ◽  
Female Group ◽  
Small Male ◽  
Adult Males ◽  
African Lions ◽  
Male Hormone

Manes are generally thought to characterize all adult male lions (Panthera leo). Here we document a population of lions in Tsavo National Park, Kenya, that is largely maneless and describe aspects of their social organization. Because Tsavo's arid landscape supports sparse prey populations, we expected that surveys of lions there would document small social groups. We hypothesized that Tsavo lions would consequently experience reduced sexual selection pressures for mane development. Adult males from Tsavo typically have sparse blond hair forming a dorsal crest, beard, chest tufts, and (or) sideburns, but lack the large flowing manes reported from other lion populations. No fully maned lions were seen. Maneless males in Tsavo appear to be well integrated into pride life, and were observed copulating, hunting, and otherwise interacting with groups of females, playing with dependent cubs, and advertising territories with scent markings and roars. Only one adult male was observed in each of five prides, which differs surprisingly from the coalitions of 2–4 pride males noted in other lion groups. However, female group size was large (mean 7.4) and comparable with what has been documented in the Serengeti and elsewhere, refuting our "group size – mane size" hypothesis. Future research should focus on the effect of Tsavo's physical and physiological effects on mane condition, and the possible correlation of male hormone levels with both manelessness and small male-group size.

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