Seasonal breeding of the narwhal (Monodon monoceros L.)

1974 ◽  
Vol 52 (3) ◽  
pp. 429-431 ◽  
Author(s):  
Robin C. Best ◽  
H. D. Fisher
Keyword(s):  
Reproductive Cycle ◽  
Gestation Period ◽  
Delphinapterus Leucas ◽  
Seasonal Breeding ◽  
Monodon Monoceros ◽  
Seasonal Breeder

The narwhal (Monodon monoceros) has been shown to be a seasonal breeder, like the closely related beluga (Delphinapterus leucas). The gestation period is estimated to be about 14 months, while the reproductive cycle is 2 or 3 years. Narwhals appear similar to other odontocetes in those reproductive aspects for which there is information.

Reproduction in the Indian mouse-tailed bat, Rhinopoma hardwickei hardwickei (Chiroptera, Rhinopomatidae)

1989 ◽  
Vol 1 (3) ◽  
pp. 255 ◽  
Author(s):  
KB Karim ◽  
S Banerjee
Keyword(s):  
Reproductive Cycle ◽  
Sexual Maturity ◽  
Uttar Pradesh ◽  
Gestation Period ◽  
Equal Frequency ◽  
Annual Reproductive Cycle ◽  
Males And Females

At and near Agra, in Uttar Pradesh, India, R. h. hardwickei had a strictly defined annual reproductive cycle. Although many females were inseminated during late February to mid April, ovulation was not recorded until 11 March. Progressively more females ovulated and conceived during the following weeks until the end of April and released one ovum from either of the ovaries with nearly equal frequency. A single conceptus was carried in the ipsilateral uterine cornu during each cycle. The gestation period was 95-100 days. Births occurred between the second week of June and the end of July. Lactation lasted at least 20 days. Females attained sexual maturity at an age of 8.5-9.0 months. Males took at least 16-17 months to attain sexual maturity. Females were segregated during lactation; during the rest of the year, males and females lived together.

Mating ecology of beluga (Delphinapterus leucas) and narwhal (Monodon monoceros)as estimated by reproductive tract metrics

2014 ◽  
Vol 31 (2) ◽  
pp. 479-500 ◽  
Author(s):  
Trish C. Kelley ◽  
Robert E. A. Stewart ◽  
David J. Yurkowski ◽  
Anna Ryan ◽  
Steven H. Ferguson
Keyword(s):  
Reproductive Tract ◽  
Delphinapterus Leucas ◽  
Monodon Monoceros

Observations on Distribution and Intraspecific Variation in Pigmentation Patterns of Odontocete Cetacea in the Western North Atlantic

1973 ◽  
Vol 30 (8) ◽  
pp. 1111-1130 ◽  
Author(s):  
M. C. Mercer
Keyword(s):  
Intraspecific Variation ◽  
North Atlantic ◽  
Intraspecific Variability ◽  
Delphinapterus Leucas ◽  
Phocoena Phocoena ◽  
Western Atlantic ◽  
Stenella Coeruleoalba ◽  
West Greenland ◽  
Monodon Monoceros

This paper comprises sight records for nine species and morphometries, color descriptions, and miscellaneous notes on the food and parasites of seven species of small odontocetes observed from West Greenland to Florida 1967–72. Of interest are the first western Atlantic extralimital record of Monodon monoceros, first Newfoundland records of Stenella coeruleoalba, and extralimital records of Delphinapterus leucas from Newfoundland. Intraspecific variability is described in the pigmentation patterns of Phocoena phocoena.

scholarly journals Surfacing Times and Dive Rates for Narwhals (Monodon monoceros) and Belugas (Delphinapterus leucas)

ARCTIC ◽  
2001 ◽  
Vol 54 (3) ◽  
Author(s):  
M.P. Heide-Jørgensen ◽  
N. Hammeken ◽  
R. Dietz ◽  
J. Orr ◽  
P.R. Richard
Keyword(s):  
Delphinapterus Leucas ◽  
Monodon Monoceros

Distribution and variation of neuropeptide Y in the brain of native Thai chicken

2020 ◽  
pp. 175815592096899
Author(s):  
Natagarn Sartsoongnoen ◽  
Boonyarit Kamkrathok ◽  
Taweesak Songserm ◽  
Yupaporn Chaiseha
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Reproductive Cycle ◽  
Food Restriction ◽  
Egg Laying ◽  
Tropical Species ◽  
Seasonal Breeding ◽  
Nucleus Paraventricularis ◽  
The Brain

Neuropeptide Y (NPY) plays a pivotal role in food intake and body weight regulation in both birds and mammals. Unlike imported broilers and layers, native Thai chicken, a tropical non-seasonal breeding species, has lower body weight and exhibits strongly maternal behaviors which, in turn, affect feeding behavior during the reproductive cycle. The aim of this study was to investigate the role(s) of NPY that might be associated with the reproductive cycle of female native Thai chickens using immunohistochemistry technique. The distributions of NPY-immunoreactive (-ir) neurons and fibers in the brain of laying and fasted chickens was also elucidated. Changes in body weight and number of NPY-ir neurons in the nucleus paraventricularis magnocellularis (PVN) were compared across reproductive stages. The results revealed that NPY-ir neurons and fibers were distributed throughout the brain with the greatest density located in the PVN. Differences in the number of NPY-ir neurons in the PVN were found across reproductive stages. The numbers were lowest in non-egg laying and egg laying stages and significantly higher during egg-incubating and chick-rearing stages. Changes in body weight were inversely related to the number of NPY-ir neurons across reproductive stages. In addition, food restriction caused an increase in NPY immunoreactivity, confirming the role of NPY in response to food restriction. Taken together, the present findings suggest that the NPYergic system in the PVN plays an important role in the regulation of food intake during the reproductive cycle in this non-seasonal breeding tropical species.

Preliminary Notes on the Occurrence and Exploitation of Smaller Cetacea in Greenland

1975 ◽  
Vol 32 (7) ◽  
pp. 1079-1082 ◽  
Author(s):  
Finn O. Kapel
Keyword(s):  
Minke Whale ◽  
Annotated Bibliography ◽  
Delphinapterus Leucas ◽  
Phocoena Phocoena ◽  
Balaenoptera Acutorostrata ◽  
White Whale ◽  
Monodon Monoceros ◽  
Pilot Whales ◽  
By Catch

Approximately 1000 common or harbour porpoises (Phocoena phocoena) are taken annually, not including the by-catch in salmon driftnets. Catches of narwhal (Monodon monoceros) and beluga (white whale, Delphinapterus leucas) fluctuate in the low to middle hundreds annually. Estimates of the annual catches in the Thule district are 100 beluga and 300 narwhals. Sporadic catches of long-finned pilot whales (Globicephata melaena) seldom exceed 100 animals per annum. Catches of minke whale (Balaenoptera acutorostrata) have risen since the late 1950s, with approximately 200 or more per annum taken in West Grenland since the mid 1960s. An annotated bibliography of titles on smaller Cetacea in Greenland is given.

An Index of the Relative Abundance of Wintering Belugas, Delphinapterus leucas, and Narwhals, Monodon monoceros, off West Greenland

1993 ◽  
Vol 50 (11) ◽  
pp. 2323-2335 ◽  
Author(s):  
M. P. Heide-Jørgensen ◽  
H. Lassen ◽  
J. Teilmann ◽  
R. A. Davis
Keyword(s):  
Relative Abundance ◽  
Delphinapterus Leucas ◽  
Late Winter ◽  
The West ◽  
Baffin Bay ◽  
West Greenland ◽  
Abundance Estimate ◽  
Monodon Monoceros ◽  
Pack Ice ◽  
Ice Conditions

Systematic aerial surveys of the wintering grounds of belugas, Delphinapterus leucas, and narwhals, Monodon monoceros, in southern Baffin Bay and northern Davis Strait were conducted in late winter of 1981, 1982, 1990, and 1991. Most belugas were found between 67°N and 69°N and none were seen more than 80 km off the coast of West Greenland. Compared with the surveys in 1981 and 1982, a decline in relative abundance of belugas along West Greenland was evident in 1991. This decline was significant at a probability level of 0.13 of the bootstrapped distribution of the combined abundance estimate. Pod sizes declined significantly between the 1981–82 and 1990–91 surveys. The variations in ice conditions between years did not seem to affect the distribution, clumping, or pod sizes of the belugas. Narwhals were widely distributed in the close pack ice offshore between 65°N and 72°N. Along the West Greenland coast, narwhals were primarily seen at the mouth of Disko Bay. No change in relative abundance or pod sizes could be detected for narwhals.

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