Movements and Home Ranges of Crocodylus johnstoni in the Lynd River, Queensland

1997 ◽  
Vol 24 (4) ◽  
pp. 379 ◽  
Author(s):  
A. D. Tucker ◽  
C. J. Limpus ◽  
H. I. McCallum ◽  
K. R. McDonald
Keyword(s):  
Field Trips ◽  
Home Ranges ◽  
Adult Males ◽  
Dominance Hierarchies ◽  
Breeding Sites ◽  
Crocodylus Johnstoni ◽  
Upstream Direction ◽  
A Minor ◽  
Australian Freshwater ◽  
Local Dominance

Movements of Australian freshwater crocodiles, Crocodylus johnstoni, were examined by a mark–recapture study spanning 20 years in the Lynd River, Queensland. After adjustment for detection bias, there was a minor upstream direction to movements. Seasonal changes of location were not evident from field trips taken only twice yearly. Annual movements averaged less than 1 km except for those of pubescent males, which appeared to be nomadic. Creche dispersal was randomly directed but associated with a threshold in mass/length ratio. On average, males were found further from previous capture sites than were females. Adults of both sexes moved shorter distances than did immature crocodiles with a clear reduction in movements occurring as mass/length ratios approached 0·17 kg per cm snout–vent length. Reduced movement at that general size ratio probably indicated the onset of territoriality associated with maturity. Females usually remained near breeding sites even in years when they did not breed. Nomadic tendencies of pubescent males are probably associated with unsuccessful attempts at entering local dominance hierarchies. Linear home ranges were estimated to be 1·5–1·9 km for immature animals, 1·2 km for pubescent females, 30·3 km for pubescent males, 0·6 km for mature females and 1·6 km for adult males.

Validation of skeletochronology to determine age of freshwater crocodiles (Crocodylus johnstoni)

1997 ◽  
Vol 48 (4) ◽  
pp. 343 ◽  
Author(s):  
Anton D. Tucker
Keyword(s):  
Age Estimation ◽  
Egg Laying ◽  
Interference Microscopy ◽  
Adult Males ◽  
Size Estimation ◽  
Thin Sections ◽  
Crocodylus Johnstoni ◽  
Old Adult ◽  
Different Seasons ◽  
Australian Freshwater

Age was estimated for wild Australian freshwater crocodiles from skeletochronology of growth marks in postoccipital osteoderms. Growth marks were distinct and counted reliably in unstained calcified thin sections (60–80 µm) viewed by Nomarski interference microscopy. The periodicity of growth marks was validated directly from crocodiles of known age (up to 19 years) and from individuals sampled sequentially in different seasons. Growth marks comprised annuli deposited in winter and zones deposited in summer. Errors in age estimation for small crocodiles resulted from difficulty in assigning the growing edge as either a zone or an annulus. No osseous remodelling was noted for immature animals. Age estimates for adult females became unreliable as previous annuli were obscured by osseous remodelling, presumably resulting from calcium mobilization by egg-laying females. Old adult males continued to deposit annuli, but these were more difficult to distinguish, being more closely spaced than in young crocodiles. Skeletochronology permitted reliable (coefficient of variation, 3·4%) and accurate (±1 year) age estimation up to about 20 years. Osteoderm dimensions were strongly correlated with average snout–vent length, mass and age and have acceptable potential as an indirect means of age and size estimation for Crocodylus johnstoni.

A Field Study of the Ontogeny of Social Behavior in the Lizard Anolis Aene Us

Behaviour ◽  
1978 ◽  
Vol 66 (1-2) ◽  
pp. 1-30 ◽  
Author(s):  
J.A. Stamps
Keyword(s):  
Food Competition ◽  
Interindividual Variation ◽  
Home Ranges ◽  
Adult Males ◽  
Intraindividual Variation ◽  
Dominance Hierarchies ◽  
Adult Females ◽  
R Ratio ◽  
Size Groups ◽  
Species Specific

AbstractThe spacing behavior, displays and aggression of hatchling and juvenile lizards (Anolis aeneus) were compared to the behavior of the adults. Tn adults these behaviors are sexually dimorphic, but juveniles of both sexes show similar behavior. Hatchling lizards a few days old have nonoverlapping home ranges or participate in dominance hierarchies of up to six steps. Status in dominance hierarchies is almost entirely size dependent. The particular type of social system shown varies with microhabitat. Juvenile home ranges are smaller than those of adults and enlarge with age. Home ranges of juveniles are more variable in size than those of adults. Temporal elements of the species specific bob pattern are very stereotyped in both juveniles and adults. Intraindividual variation in display element duration is low and interindividual variation high in all age and size groups. However, mean duraton of elements is longer for larger lizards. Two other displays are significantly more variable in juveniles than in adults. Most of this variation is due to added interindividual variance in juvenile display elements. Juveniles and adults of both sexes are able to give all displays except courtship displays. The frequency with which certain displays are given is significantly different for juveniles, adult females and adult males. Juveniles are more apt to give certain aggressive displays than are adults of either sex. Longterm ontogenetic studies of individual females indicates that initially they give the aggressive displays characteristic of juveniles in general, but that the frequency of these displays decrease when they become sexually mature. When territorial resident lizards of any age are exposed to tethered intruders they react aggressively. Aggressive responses were ranked and aggression computed for certain size ratios of intruder and resident juveniles (I/R ratio). This aggression was compared to that predicted on the basis of food competition between different lizard size ratios. At both large and small lizard size ratios (I/R) juvenile Anolis aeneus are more aggressive than are either adult males or adult females at the same size ratios. This added aggressiveness to very large and very small intruders cannot be explained in terms of food competition between juvenile lizards of different sizes.

Spacing, movements, and habitat selection of the river otter in boreal Alberta

1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero
Keyword(s):  
Lontra Canadensis ◽  
Home Ranges ◽  
Adult Males ◽  
Movement Rates ◽  
River Otters ◽  
Aquatic Mammal ◽  
Adult Females ◽  
Two Factors ◽  
Bog Lakes ◽  
Selection Of

Seasonal spacing patterns, home ranges, and movements of river otters (Lontra canadensis) were studied in boreal Alberta by means of radiotelemetry. Adult males occupied significantly larger annual home ranges than adult females. Males' ranges overlapped those of females and also each other's. In winter, home ranges of males shrank and showed less overlap. Otters often associated in groups, the core members typically being adult females with young, or adult males. Otters tended to be more solitary in winter. In winter, movement rates of all sex and age classes were similar, and much reduced for males compared with those in other seasons. These data indicated a strong limiting effect of winter ice on behaviour and dispersion. We tested the hypothesis that otters select water bodies in winter on the basis of the suitability of shoreline substrate and morphology for dens with access both to air and to water under ice. Intensity of selection was greatest in winter, with avoidance of gradually sloping shorelines of sand or gravel. Adults selected bog lakes with banked shores containing semi-aquatic mammal burrows, and lakes with beaver lodges. Subadults selected beaver-impounded streams. Apart from human harvest, winter habitats and food availability in such habitats are likely the two factors most strongly limiting otter density in boreal Alberta.

Dispersal patterns in a regional koala population in south-east Queensland

2003 ◽  
Vol 30 (3) ◽  
pp. 281 ◽  
Author(s):  
David S. Dique ◽  
Jim Thompson ◽  
Harriet J. Preece ◽  
Deidré L. de Villiers ◽  
Frank N. Carrick
Keyword(s):  
Urban Areas ◽  
Home Ranges ◽  
Adult Males ◽  
Dispersal Patterns ◽  
Young Males ◽  
Straight Line ◽  
The Social ◽  
Straight Line Distance ◽  
Males And Females ◽  
Natal Home

Koala dispersal was investigated as part of a detailed ecological study of a nationally significant koala population located 20 km south-east of Brisbane, Queensland. From 1996 to 2000, 195 koalas from three sites were captured and fitted with radio-collars. A total of 40 koalas (23 males and 17 females) dispersed from these sites. Most (93%) dispersing individuals were 20–36 months of age. Three adult females (more than 36 months old) dispersed and no adult males dispersed during the study. A significantly higher proportion of young males dispersed than females. Dispersal occurred between June and December, with most dispersal of males commencing in July and August and that of females commencing between September and November prior to, and early in, the annual breeding season. The mean straight-line distance between the natal and breeding home ranges for males and females was similar and was measured at 3.5 km (range 1.1–9.7 km) and 3.4 km (range 0.3–10.6 km) respectively. Dispersing males and females tended to successfully disperse south and west of their natal home ranges and were generally unable to successfully disperse to urban areas within the study area, as a high proportion of the mortality of dispersing koalas was associated with attacks by domestic dogs and with collisions with vehicles on roads. Information from other studies indicates that most young koalas disperse from their natal areas. It is likely that the social behaviour and mating systems of koala populations provide mechanisms for young koalas to disperse. The potential role of dispersal in the dynamics of regional koala populations is discussed.

Cimetidine-induced prolactin release in rats The effect of sex and gonadal steroids

1987 ◽  
Vol 114 (2) ◽  
pp. 178-184 ◽  
Author(s):  
Hajime Watanobe ◽  
Kazuo Takebe
Keyword(s):  
Anterior Pituitary ◽  
Male Rats ◽  
Minor Role ◽  
Adult Males ◽  
Adult Age ◽  
Significant Difference ◽  
Males And Females ◽  
Plasma Prl ◽  
A Minor

Abstract. The cimetidine-induced plasma Prl response was examined in rats of both sexes. First, 10 week old intact adult males and females (dioestrous) were compared. There was no significant difference in the Prl response to cimetidine between the two groups, despite the fact that in adult females the anterior pituitary Prl content was 4 times greater than in males. Second, the effect of gonadal state in adult age on the Prl response to cimetidine was examined in both sexes. In male rats, gonadectomy at the age of 6 weeks significantly reduced the plasma Prl response as well as the pituitary Prl content, both of which were sufficiently restored by testosterone replacement. However, in females, neither gonadectomy at the age of 6 weeks nor subsequent oestradiol replacement affected the Prl response to cimetidine, despite the fact that gonadectomy significantly reduced and oestradiol treatment significantly enhanced the pituitary Prl content. Third, possible permanent effects of the postnatal gonadal milieu on the cimetidine-induced Prl response and the pituitary Prl content were examined in both sexes by castration at varying postnatal ages. The ratio of plasma Prl response to pituitary Prl content was similar in all castrated males. In females, however, the ratio decreased with increasing castration age. In conclusion, the mechanism of cimetidine-induced Prl release is less sex-dependent than are the mechanisms of Prl release by other Prl secretagogues. First, this may be due to a minor role of oestrogen in females in determining the Prl response to cimetidine. Second, the postnatal ovarian secretions may exert a permanent inhibition of the development of the cimetidine-mobilized anterior pituitary Prl pool.

Observations on Activity Patterns, Population and Den Characteristics of The Water Rat Hydromys chrysogaster Along Badger Creek, Victoria.

1995 ◽  
Vol 18 (1) ◽  
pp. 71
Author(s):  
J.L. Gardner ◽  
M. Serena
Keyword(s):  
Population Density ◽  
Activity Patterns ◽  
Home Ranges ◽  
Adult Males ◽  
Fish Farms ◽  
Age Classes ◽  
Irrigation Channels ◽  
In Captivity ◽  
In The Wild ◽  
Hydromys Chrysogaster

The Water Rat Hydromys chrysogaster is Australia's largest amphibious rodent, occupying freshwater rivers, lakes, and coastal and estuarine habitats throughout the continent (Watts and Aslin 1981). Little is known of the species' social organisation or use of space in the wild although Harris (1978) suggested that adults might be intrasexually aggressive. The home ranges of all sex and age classes overlap to some extent but home ranges of adults of the same sex appear to overlap less (Harris 1978). Adult males occupy the largest home ranges which overlap those of one or more females. In captivity individuals kept in groups form hierarchies in which only the dominant females usually breed successfully (Olsen 1982). Fighting occurs primarily among males, with the highest incidence of injuries observed at the beginning of the main September-March breeding season (Olsen 1980, 1982). The results of trapping studies indicate that population density may vary considerably, with the greatest numbers of animals typically occupying man-modified habitats such as irrigation channels or fish farms (McNally 1960, Watts and Aslin 1981, Smales 1984). Aggressive behaviour appears to be related to pelage colour (phenotype) and population density; the higher the density the greater the number of injured individuals (Olsen 1980).

scholarly journals Movements of Subadult Male Grizzly Bears, Ursus arctos, in the Central Canadian Arctic

2004 ◽  
Vol 118 (2) ◽  
pp. 239 ◽  
Author(s):  
Robert J. Gau ◽  
Philip D. McLoughlin ◽  
Ray Case ◽  
H. Dean Cluff ◽  
Robert Mulders ◽  
...  
Keyword(s):  
Home Range ◽  
Long Range ◽  
Rangifer Tarandus ◽  
Ursus Arctos ◽  
Canadian Arctic ◽  
Grizzly Bears ◽  
Home Ranges ◽  
Adult Males ◽  
Subadult Male ◽  
Daily Movement

Between May 1995 and June 1999, we equipped eight subadult male (3-5 yrs old) Grizzly Bears (Ursus arctos) with satellite radio-collars within a study area of 235,000 km2, centred 400 km northeast of Yellowknife, Northwest Territories, Canada. Subadult male annual home ranges were extraordinarily large (average = 11,407 km2, SE = 3849) due, in part, to their movement's occasional linear directionality. We believe their long-range linear movements may reflect some individuals tracking the migration of Caribou (Rangifer tarandus). Seasonal daily movement patterns were similar to adult males that were previously reported. The areas used by these bears are the largest ranges reported for any Grizzly Bears and the scale of their movements may put individual bears in contact with humans even when developments are hundreds of kilometres from the central home range of an animal.

Dispersal and site fidelity in Blue Grouse

1983 ◽  
Vol 61 (3) ◽  
pp. 570-573 ◽  
Author(s):  
Ian G. Jamieson ◽  
Fred C. Zwickel
Keyword(s):  
Site Fidelity ◽  
General Area ◽  
Adult Males ◽  
Same Sex ◽  
Breeding Sites ◽  
Sibling Pairs ◽  
Dendragapus Obscurus ◽  
Opposite Sex ◽  
Juvenile Males ◽  
Old Females

Ten years of banding and censusing data from Blue Grouse (Dendragapus obscurus) were analyzed with respect to dispersal of juveniles and site fidelity of yearlings and adults. Juvenile females dispersed farther than juvenile males. In sibling pairs of the same sex, brothers settled closer to one another than sisters. In sibling pairs with birds of opposite sex, females dispersed farther than males. Adult males first established territories close to where they had been sighted as yearlings, or nonterritorial adults, and most females returned in spring to the same general area where they had previously nested. Two-year-old females showed less fidelity to breeding sites they had used as yearlings than older females to sites they had used in previous years.

scholarly journals Osmoregulatory mechanisms of the Australian freshwater crocodile, Crocodylus johnstoni , in freshwater and estuarine habitats

1999 ◽  
Vol 169 (3) ◽  
pp. 215-223 ◽  
Author(s):  
L. E. Taplin ◽  
G. C. Grigg ◽  
L. A. Beard ◽  
T. Pulsford
Keyword(s):  
Crocodylus Johnstoni ◽  
Freshwater Crocodile ◽  
Australian Freshwater

Terrestrial activity and summer home range of the mole salamander (Ambystoma talpoideum)

1981 ◽  
Vol 59 (2) ◽  
pp. 315-322 ◽  
Author(s):  
Raymond D. Semlitsch
Keyword(s):  
South Carolina ◽  
Home Range ◽  
Home Ranges ◽  
Breeding Sites ◽  
Carolina Bays ◽  
Mole Salamander ◽  
Ambystoma Talpoideum ◽  
Terrestrial Habitats ◽  
Activity Center ◽  
Two Populations

The terrestrial activity and summer home range of Ambystoma talpoideum is described in two populations in South Carolina. Emigration of adults from breeding sites occurred from March through May during 1979 and 1980. Adults spent 237–354 days in terrestrial habitats before returning to breeding sites during autumn and early winter. Females spent significantly more time in terrestrial habitats than males. Movement of A. talpoideum into and out of the breeding sites around the perimeter of the Carolina bays was nonrandom. Salamanders used corridors of dense vegetation more frequently than open, grassy shoreline areas. Emigration of individual adults to summer home ranges occurred within several nights and summer home ranges were established 81–261 m from the edge of the bays. Juveniles emigrated significantly shorter distances (12–67 m) than adults. Summer home ranges comprised several focal points of activity or "activity centers." The area of each activity center was relatively constant among individuals (0.02–0.21 m2) when compared with the area of a "minimum polygon" home range (0.11–23.3 m2). Ambystoma talpoideum inhabited burrow systems within each activity center. Burrows ran parallel to the surface of the forest floor and averaged 1.7 cm in diameter and 4.7 cm below the surface.

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