Body size, diet and reproductive ecology of Coluber hippocrepis in the Rif (Northern Morocco)

2004 ◽  
Vol 25 (3) ◽  
pp. 287-302 ◽  
Author(s):  
Juan Pleguezuelos ◽  
Soumia Fahd
Keyword(s):  
Body Size ◽  
Sexual Maturity ◽  
Prey Size ◽  
Reproductive Ecology ◽  
Size Difference ◽  
Southern Europe ◽  
Strait Of Gibraltar ◽  
Dietary Shift ◽  
Intersexual Difference ◽  
Whip Snake

AbstractAlthough it is generally assumed that the Horseshoe Whip Snake (Coluber hippocrepis) originated in northern Africa, its biology and ecology has been studied mainly in southern Europe. In this paper we report on morphology, feeding, and reproductive ecology of Coluber hippocrepis in the Rif region (northern Morocco). Males attained larger sizes than did females, but there was no body-size difference between populations separated by the Strait of Gibraltar. The species feeds exclusively on vertebrates: mammals (45%), reptiles (28%), birds (17%), and amphibians (10%). There was an ontogenetic dietary shift in terms of frequency of prey consumed and in terms of prey size; moreover, an intersexual difference in prey frequency was found. Sexual maturity was attained at 540 mm snout-vent length (SVL) in males, and 720 mm SVL in females. Males showed a vernal spermatogenic cycle. Oviposition occurred at the beginning of summer, and offspring were observed in the field during September.

Reproductive Ecology of The Allied Rock-wallaby, Petrogale assimilis.

1996 ◽  
Vol 19 (2) ◽  
pp. 209
Author(s):  
R. Delaney
Keyword(s):  
Life History ◽  
Sex Ratio ◽  
Sexual Maturity ◽  
Post Partum ◽  
Reproductive Ecology ◽  
Oestrous Cycle ◽  
Embryonic Diapause ◽  
Minimum Age

Petrogale assimilis has a typical life history and reproductive ecology for a macropodid of its size. Both sexes are capable of reproducing continuously; gestation is about the same length as the oestrous cycle (approximately one month); a single young is born and, a post-partum oestrus and embryonic diapause probably occurs. The sex ratio of young is unbiased. Pouch young remain permanently attached to the teat until 110 - 143 days (n=11). Permanent exit from the pouch occurs at 180 - 231 days (mean=201 days, n=25), and weaning occurs between 267 - 387 days (n=5). Sexual maturity occurs at a minimum age of 17.5 months in females and 23 months in males.

scholarly journals Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae), off Uruguay and northern Argentina

2016 ◽  
Vol 14 (3) ◽  
Author(s):  
Santiago A. Barbini ◽  
Luis O. Lucifora
Keyword(s):  
Body Size ◽  
Diet Composition ◽  
Prey Size ◽  
Prey Availability ◽  
Feeding Habits ◽  
Warm Season ◽  
Cold Season ◽  
The North ◽  
Multiple Hypothesis ◽  
Modelling Approach

ABSTRACT The eyespot skate, Atlantoraja cyclophora, is an endemic species from the southwestern Atlantic, occurring from Rio de Janeiro, Brazil, to northern Patagonia, Argentina. The feeding habits of this species, from off Uruguay and north Argentina, were evaluated using a multiple hypothesis modelling approach. In general, the diet was composed mainly of decapod crustaceans, followed by teleost fishes. Molluscs, mysidaceans, amphipods, isopods, lancelets and elasmobranchs were consumed in lower proportion. The consumption of shrimps drecreased with increasing body size of A. cyclophora. On the other hand, the consumption of teleosts increased with body size. Mature individuals preyed more heavily on crabs than immature individuals. Teleosts were consumed more in the south region (34º - 38ºS) and crabs in the north region (38º - 41ºS). Shrimps were eaten more in the warm season than in the cold season. Prey size increased with increasing body size of A. cyclophora , but large individuals also consumed small teleosts and crabs. Atlantoraja cyclophora has demersal-benthic feeding habits, shifts its diet with increasing body size and in response to seasonal and regional changes in prey availability and distribution.

Body Size and the Timing of Sexual Maturity

2017 ◽  
pp. 341-374
Author(s):  
Kim Hill ◽  
A. Magdalena Hurtado
Keyword(s):  
Body Size ◽  
Sexual Maturity

The relation of body size of male humpback whales to their social roles on the Hawaiian winter grounds

2002 ◽  
Vol 80 (11) ◽  
pp. 1938-1947 ◽  
Author(s):  
Scott S Spitz ◽  
Louis M Herman ◽  
Adam A Pack ◽  
Mark H Deakos
Keyword(s):  
Body Size ◽  
Sexual Maturity ◽  
Social Roles ◽  
Male Partner ◽  
Humpback Whales ◽  
Male Partners ◽  
The Social ◽  
Reproductive Unit ◽  
Significant Size

We examined the relation of body length of male humpback whales (Megaptera novaeangliae) to the social roles they adopted on the Hawaiian winter grounds: principal escort in a competitive group, secondary escort, lone escort to a mother–calf pair, male partner in a dyad, and singer. Using underwater videogrammetry, we measured body lengths of 17 principal escorts, 68 secondary escorts, 40 single escorts, 17 male partners, and 8 singers. Results revealed that (i) principal escorts were, on average, significantly larger than males in each of the remaining social roles except singer, (ii) singers were significantly larger than male partners, (iii) there were no significant size differences among secondary escorts, single escorts, or male partners. Further, principal escorts tended to be the largest or second-largest male within their individual competitive group. All principal escorts were of sizes that indicated a 0.81 probability or better of sexual maturity, based on whaling data. In comparison, more than half of the male partners, almost one-third of the secondary escorts, and one-fifth of the single escorts were of sizes that indicated a 0.5 probability or less of sexual maturity. Seven of the eight singers had a 0.9 probability or better of sexual maturity and the eighth singer a 0.5 probability. However, the data for singers are too few to allow firm conclusions to be reached about the relation of body size to singing. Overall, our findings suggest that body size confers an advantage in physical competition between male humpback whales, and that a large proportion of males adopting the role of secondary escort, single escort, and partner are likely to be sexually immature. Additionally, the competitive group appears to be a major reproductive unit in terms of bringing together a receptive female and potential mates.

The Ecology of Rattus lutreolus III*. The Rise and Fall of a Commensal Population

1980 ◽  
Vol 7 (2) ◽  
pp. 199 ◽  
Author(s):  
RW Braithwaite
Keyword(s):  
Body Size ◽  
Habitat Use ◽  
Breeding Season ◽  
Sexual Maturity ◽  
Free Living ◽  
Mark Recapture

A free-living population of R. lutreolus living in and around the zoo enclosures of the Sir Colin MacKenzie Fauna Park at Healesville was studied for 27 months by use of mark-recapture trapping techniques. The demography of this population is compared with that of a natural heathland population. The breeding season was 2-3 months longer, growth of juveniles was more rapid, sexual maturity earlier, minimum survival shorter, body size larger, and habitat use less restricted in the commensal population. The evolution of the population and its decline are discussed.

A Reconsideration of Aspects of Growth, Reproduction, and Behavior of the White Whale (Delphinapterus leucas), with Reference to the Cumberland Sound, Baffin Island, Population

1971 ◽  
Vol 28 (9) ◽  
pp. 1309-1318 ◽  
Author(s):  
P. F. Brodie
Keyword(s):  
Body Size ◽  
Sexual Maturity ◽  
Delphinapterus Leucas ◽  
Corpora Lutea ◽  
Island Population ◽  
Baffin Island ◽  
White Whale ◽  
Cumberland Sound ◽  
And Behavior ◽  
Commercial Hunting

The beluga or white whale, Delphinapterus leucas (Pallas), was studied in Cumberland Sound, Baffin Island. Layering in teeth and mandibles plus body size were used to determine age. Sexual maturity is attained at 5 years for females and at 8 years for males, with potential life span estimated to be 30 years. Whitening of the skin begins after 6 years.Multiple ovulations and accessory corpora lutea are typical of beluga. The breeding season is in May, and after 14.5 months gestation single births occur in late July or early August. Lactation lasts about 2 years, resulting in a 3-year reproductive cycle. Tooth eruption begins late in the 2nd year with partial eruption by the 3rd. This population appears to have been overexploited by commercial hunting. Productivity estimates for this species are 43% of those implied in previous studies.

Comparative life history features of the western spotted frog, Rana pretiosa, from low- and high-elevation populations

1975 ◽  
Vol 53 (9) ◽  
pp. 1254-1257 ◽  
Author(s):  
Lawrence E. Licht
Keyword(s):  
British Columbia ◽  
Life History ◽  
Body Size ◽  
Sexual Maturity ◽  
High Elevation ◽  
The Body ◽  
Female Fecundity ◽  
Size At Sexual Maturity ◽  
Rana Pretiosa

Comparisons are made of life history features of the western spotted frog, Rana pretiosa pretiosa, living at 70 m in southwestern British Columbia, and 2600 m in Yellowstone Park, Wyoming.Lowland tadpoles remain longer as larvae and transform at twice the body size as highland tadpoles.Growth rates of juveniles and adults are rapid in the lowland population and the same amount of growth achieved by them in 2–3 years takes 8–10 years for highland frogs.Body size at sexual maturity is the same for frogs from both populations, but B.C. frogs breed at half the age of Wyoming frogs. Female fecundity, the number of eggs at spawning, is the same, but lowland females breed annually, while high-elevation females breed only every 2 or 3 years.Various explanations are put forth to account for observed differences.

The Body-Size-Prey-Size Hypothesis: A Defense

Ecology ◽  
1986 ◽  
Vol 67 (1) ◽  
pp. 260-261 ◽  
Author(s):  
Thomas W. Schoener ◽  
Jonathan Roughgarden ◽  
Tom Fenchel
Keyword(s):  
Body Size ◽  
Prey Size ◽  
The Body
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