Mindestanforderungen an die artgerechte Haltung von Krokodilen in privaten Terrarien und zoologischen Einrichtungen

The minimum requirements for the keeping of crocodiles in private and public institutions are set up by a collective of authors. Important aspects such as the design of enclosures, secure handling and keeping, thermoregulation, protection of animals, feeding, behavioural enrichment and diseases and their prophylaxis are important topics. The authors critically deal with existing guidelines and give suggestions on how crocodiles can be kept appropriately and according to existing laws at the same time.Special attention is given to the aspects of current legislation. It is stressed that there should be given proper attention to the qualification of the keeping institution as to the biology of the animals as well as to security aspects.A table of species completes the text with a short array of important features to be considered in the keeping of crocodiles.     

Influence of recombinant bovine growth hormone on growth and feed intake in juvenile Nile crocodiles (Crocodylus niloticus)

• 1.1. Slow-growing juvenile Nile crocodiles were injected with recombinant bovine growth hormone (rbGH) once a week for 6 weeks and then re-treated after 4 weeks.
• 2.2. The feed intake of the treated crocodiles was 26 g/kg/meal during the three periods, while the intakes of the controls were 15, 20 and 2 g/kg.
• 3.3. The treated gained 2.3 and 0.9%/week in weight during the first and second injection period and the feed conversion efficiencies were 28 and 13%. The controls lost weight.
• 4.4. The treated animals grew at rates of 0.98 and 0.43%/week during the first and the second injection period.
• 5.5. Bovine GH enhances growth in juvenile crocodiles and seems to have less adverse effects than human GH.

     

Shifts in hatching date of American crocodile (Crocodylus acutus) in southern Florida

Globally temperature of marine environments is on the rise and temperature plays an important role in the life-history of reptiles. In this study, we examined the relationship between sea surface temperature and average date of hatching for American crocodiles (Crocodylus acutus) over a 37-year period at two nesting sites, Everglades National Park and Florida Power and Light Turkey Point Power Plant site in southern Florida. Our results indicate that hatch dates are shifting 1.5 days earlier every two years and at half that rate for the Turkey Point site, and with every 1 °C degree increase in temperature, hatching occurs about 10 days earlier in the Everglades and 6 days earlier at Turkey Point. Our results on shifting hatch dates for American crocodiles provide further details about the impacts of temperature change on crocodile life history and suggest that increased temperature may affect their phenology.     

中国蝎目名录(蛛形纲:蝎目)

本文根据我国蝎目种类已有的记述,归纳列出5科9属19种和亚种的学名、引证及其地理分布,以供今后研究参考.     

Natal origin and dispersal of problem saltwater crocodiles in the Darwin Harbor,Australia

Management programs that successfully recovered wild saltwater crocodile (Crocodylus porosus) populations in the Northern Territory of Australia did so with an expanding commitment to maintaining public safety. One aspect of the program is the ongoing removal of resident and immigrant crocodiles within Darwin Harbor (since 1979), the main urban center. We determined the likely sources of crocodiles caught as problem animals between 2015–2017 by comparing recently developed methods for population assignment. Depending on the assignment model used, we estimated that between 30% and 50% of crocodiles in Darwin Harbor originated from the Adelaide and Mary rivers, and the Kakadu region east of Darwin, and between 20% and 30% of crocodiles originated from the Finniss, Reynolds, and Daly rivers southwest of Darwin. Saltwater crocodiles occur at particularly high densities in these catchments. The remainder came from a mixture of different sources across the Northern Territory. The most common animals captured were immature (150–180 cm) males that have traveled 100–200 km. We did not identify any relationships between the distance from the inferred origin to Darwin Harbor and the size and sex of the crocodiles, or the year of capture. The targeted removal of crocodiles from specific sites such as Darwin Harbor, near where most people live, improves public safety in the highest risk areas, without compromising abundant source populations in most areas.     

中国伪蝎名录（蛛形纲：伪蝎目）

本文根据我国伪蝎目已有种类记述,归纳并列出10科34属73种（包括亚种）伪蝎的中文名、拉丁学名、引证及其地理分布,以供今后研究参考。     

Determinants of habitat selection by hatchling Australian freshwater crocodiles

Animals almost always use habitats non-randomly, but the costs and benefits of using specific habitat types remain unknown for many types of organisms. In a large lake in northwestern Australia (Lake Argyle), most hatchling (<12-month-old) freshwater crocodiles (Crocodylus johnstoni) are found in floating vegetation mats or grassy banks rather than the more widely available open banks. Mean body sizes of young crocodiles did not differ among the three habitat types. We tested four potential explanations for non-random habitat selection: proximity to nesting sites, thermal conditions, food availability, and exposure to predation. The three alternative habitat types did not differ in proximity to nesting sites, or in thermal conditions. Habitats with higher food availability harboured more hatchlings, and feeding rates (obtained by stomach-flushing of recently-captured crocodiles) were highest in such areas. Predation risk may also differ among habitats: we were twice as likely to capture a crocodile after seeing it in open-bank sites than in the other two habitat types. Thus, habitat selection of hatchling crocodiles in this system may be driven both by prey availability and by predation risk.     

Diet and body condition of cave‐dwelling dwarf crocodiles (Osteolaemus tetraspis,Cope 1861) in Gabon

We present the first ever observations of dwarf crocodiles (Osteolaemus tetraspis) selectively utilizing a cave ecosystem. We analysed crocodile diet to preliminarily assess the degree of ecological isolation of cave‐dwelling crocodiles from their forest‐dwelling conspecifics despite their physical proximity. We additionally conducted the first study of body condition of dwarf crocodiles and compared cave‐dwelling individuals to surface‐dwelling individuals from a variety of alternative habitats and sites as a means to better understand the implications of a semihypogean life on this species. Crocodiles captured in the caves appeared to forage exclusively in the caves and ate mostly cave crickets and bats, whereas crocodiles captured in the surrounding forest habitat consumed primarily freshwater crustaceans and insects and were not found to consume cave‐dwelling prey. Juvenile cave crocodiles had significantly higher body condition compared to juvenile forest crocodiles, which did not vary amongst forest locations. The difference in body condition between adult cave and forest crocodiles was not statistically significant despite also being higher; we suspect this is an artefact of the low sample size rather than a real nondifference. Forest adult crocodiles generally had significantly higher body condition than juveniles, but did not vary by site or habitat. This lack of variation suggests that habitat type is not the most important factor influencing dwarf crocodile body condition. Our results provide a unique insight into facultative cave use by a principally surface‐dwelling species and reinforce the necessity for further research into this unique system to better understand the evolutionary‐scale implications of cave habitat use by dwarf crocodiles.     

Hematologic and plasma biochemical reference intervals for Morelet's crocodiles (Crocodylus moreletii) in the northern wetlands of Campeche, Mexico

Health surveys and hematologic and plasma biochemical analyses were conducted in 52 free-ranging and 51 captive Morelet's crocodiles (Crocodylus moreletii) in Campeche, Mexico, March-September 2007. Blood samples from 92 crocodiles (45 free-ranging and 47 captive) were collected for hematologic and plasma biochemical analyses. Average values of erythrocytes of free-ranging crocodiles were 1,046,166 cells/μl, and total white cells were 1.03 × 10(4) cells/μl. Captive crocodiles had erythrocyte and leukocyte values of 1,100,416 cells/μl and 8.51 × 10(3) cells/μl, respectively. There were no significant differences in values of erythrocytes or in hematocrit between free-ranging and captive crocodiles, or between sexes, or among size classes. Counts of leukocytes in free-ranging crocodiles were significantly higher than in captive individuals. The mean values of plasma analytes were 69.55 mg/l (glucose), 250.14 mg/l (cholesterol), 3.04 mg/l (uric acid), 2.70 mg/l (creatinine), and 20.20 IU/l (alanine aminotransferase). There were significant differences in cholesterol between free-ranging and captive crocodiles and between sexes.     

Recovery of saltwater crocodiles following unregulated hunting in tidal rivers of the Northern Territory,Australia

Saltwater crocodiles (Crocodylus porosus) in the Northern Territory of Australia were protected in 1971, after a severe population decline resulting from 26 yr of intense commercial hunting. By that time wild saltwater crocodiles were rarely sighted anywhere and they were commercially extinct in areas where they had once been abundant. Standardized monitoring by spotlight surveys started in 1975 and provided relative density indices over time (1975–2009) as a unique record of the post-protection recovery of a wild crocodilian population. We examined the survey data for populations at 12 major tidal rivers, individually and as a single subpopulation. The pattern of recovery in the subpopulation in both abundance and biomass was approximated by logistic curves, predicting 5.26 non-hatchling crocodiles weighing 387.64 kg sighted per kilometer of river in 2010. We predicted potential carrying capacity as 5.58 non-hatchling crocodiles (5.73% higher than 2010) weighing 519.0 kg (25.31% higher than 2010). Individual rivers showed largely different abundance and biomass among rivers. The statistical model that best described the recovery in individual rivers was not always logistic. However, where it was logistic, expected carrying capacity of different rivers showed considerable variation in abundance and biomass. The variation indicates different habitat quality among the rivers. Recovery occurred despite various consumptive uses, particularly a widespread egg-harvest program, which has been an integral part of the incentive-driven conservation program for saltwater crocodiles in the Northern Territory since 1983. We suggest that the saltwater crocodile population of the Northern Territory is achieving full recovery from uncontrolled hunting in 1945–1971. Although saltwater crocodiles are considered an important natural resource, their increase in number, size, and distribution is posing management issues for public safety. Continuation of human–crocodile conflict management through public education and strategic removal of problem crocodiles will be essential. © 2011 The Wildlife Society.     

Apex predatory sharks and crocodiles simultaneously scavenge a whale carcass

Scavenging is an important component to the overall ecology of consumers in virtually all ecosystems on Earth. Given the energetic benefits of foraging on these resource subsidies, opportunistic predators will adjust their behaviors accordingly to maximize access. One of the many consequences of large-scale scavenging opportunities is species interactions that are rarely observed in nature. Here we describe the first published record of predatory sharks (tiger sharks, Galeocerdo cuvier) and saltwater crocodiles (Crocodylus porosus) foraging together in space and time, as documented on a large whale carcass off Western Australia. We report on and discuss the behaviors of the sharks and crocodiles in the hope of shedding new light on the interactions between apex predators that are rarely seen together, but may overlap under specific contexts.     

Epidemic patch models applied to pandemic influenza: Contact matrix, stochasticity, robustness of predictions

Due to the recent emergence of H5N1 virus, the modelling of pandemic influenza has become a relevant issue. Here we present an SEIR model formulated to simulate a possible outbreak in Italy, analysing its structure and, more generally, the effect of including specific details into a model. These details regard population heterogeneities, such as age and spatial distribution, as well as stochasticity, that regulates the epidemic dynamics when the number of infectives is low. We discuss and motivate the specific modelling choices made when building the model and investigate how the model details influence the predicted dynamics. Our analysis may help in deciding which elements of complexity are worth including in the design of a deterministic model for pandemic influenza, in a balance between, on the one hand, keeping the model computationally efficient and the number of parameters low and, on the other hand, maintaining the necessary realistic features.     

Nest‐site selection by crocodiles at a rocky site in the Australian tropics: Making the best of a bad lot

Most animals select nest sites non‐randomly, reflecting benefits of specific locations or incubation conditions for offspring viability as well as risks or costs to the reproducing adult. If few or no available nest sites offer suitable conditions, we expect animals to make the best of a bad lot, by selecting nest sites that provide the best conditions available. In tropical north‐western Australia, freshwater crocodiles (Crocodylus johnstoni: Crocodylidae) in a large artificial lake (Lake Argyle) experience this challenge: the types of nest sites used by this species in other parts of its range (moist, shaded sandy soils, far from the water's edge) are scarce. Measurements of 89 crocodile nests and 89 test holes (abandoned attempts at nesting) at Lake Argyle, and 28 nests on the nearby Ord River, show that most areas along the lakeshore are too steep and rocky for nesting. Crocodiles at the lake therefore are forced to nest at sites that are sun‐exposed, in dry gravelly substrates, and close to the water's edge. Comparisons of test holes and actual nests within such areas show that nesting crocodiles actively select sites that are less rocky, are suitable hydrically, and that provide stable thermal regimes. Those hydric and thermal attributes allow successful development of the offspring. The ability of freshwater crocodiles in Lake Argyle to flexibly modify their nest‐site selection criteria, under severe constraints enforced by this open rocky landscape, are critical to the species' success in exploiting the opportunity created by the dam's construction.     

A sampling design and model for estimating abundance of Nile crocodiles while accounting for heterogeneity of detectability of multiple observers

As part of the development of a management program for Nile crocodiles in Lake Nasser, Egypt, we used a dependent double-observer sampling protocol with multiple observers to compute estimates of population size. To analyze the data, we developed a hierarchical model that allowed us to assess variation in detection probabilities among observers and survey dates, as well as account for variation in crocodile abundance among sites and habitats. We conducted surveys from July 2008–June 2009 in 15 areas of Lake Nasser that were representative of 3 main habitat categories. During these surveys, we sampled 1,086 km of lake shore wherein we detected 386 crocodiles. Analysis of the data revealed significant variability in both inter- and intra-observer detection probabilities. Our raw encounter rate was 0.355 crocodiles/km. When we accounted for observer effects and habitat, we estimated a surface population abundance of 2,581 (2,239–2,987, 95% credible intervals) crocodiles in Lake Nasser. Our results underscore the importance of well-trained, experienced monitoring personnel in order to decrease heterogeneity in intra-observer detection probability and to better detect changes in the population based on survey indices. This study will assist the Egyptian government establish a monitoring program as an integral part of future crocodile harvest activities in Lake Nasser. © 2012 The Wildlife Society.     

Effect of human-mediated migration and hybridization on the recovery of the American crocodile in Florida (USA)

The American crocodile (Crocodylus acutus) is a large apex predator with an extensive but fragmented range. Crocodylus acutus suffered a population crash and was almost extirpated from Florida (USA) during the 1970s; however, in 2007 it was federally downlisted from endangered to threatened based on an increase of suitable habitat and a growing population. A genetic assessment of this population has not been performed even though foreign crocodiles have been released into Florida waters. Herein, we use mitochondrial and nuclear DNA markers to characterize relationships among American crocodiles along the southern coast of Florida and reference samples from other countries. We detected inter- and intra-specific hybridization and unexpected population structure attributed to human-mediated migration of crocodiles from Latin America and the Greater Antilles. Our results suggest that the population size of crocodiles actually native to Florida should be reevaluated, particularly in light of ongoing admixture in this population. We reemphasize the utility of genetic markers in conservation and management programs for endangered species; especially those that can hybridize with closely related congeners. The American crocodile in Florida has recovered owing to successful conservation initiatives, but a long-term management protocol that takes genetic data into account is still needed.     

扬子鳄的起源

介绍了现存鳄彼此间的亲缘关系、扬子鳄起源的时间和地点。主要结论可归纳如下：①现存鳄类在科、属、种分类上都存在不同意见;②扬子鳄与密河鳄被分在同一属内,但两者之间的亲缘关系存在争议,两者在形态、生化、细胞、分子生物学上差异很大;③Stell认为扬子鳄在中新世开始出现,作者认为它可能起源于渐新世或中新世早期;④Stell认为分布于北美的汤氏鳄（A.thomsoni)可能是扬子鳄的祖先类型,而另一些学者认为扬子鳄起源于亚洲的可能性更大些。     

The comparative energetics of the turtles and crocodiles

The Add‐my‐Pet collection of data on energetics and Dynamic Energy Budget parameters currently contains 92 species of turtles and 23 species of crocodiles. We discuss patterns of eco‐physiological traits of turtles and crocodiles, as functions of parameter values, and compare them with other taxa. Turtles and crocodiles accurately match the general rule that the life‐time cumulated neonate mass production equals ultimate weight. The weight at birth for reptiles scales with ultimate weight to the power 0.6. The scaling exponent is between that of amphibians and birds, while that for mammals is close to 1. We explain why this points to limitations imposed by embryonic respiration, the role of water stress and the accumulation of nitrogen waste during the embryo stage. Weight at puberty is proportional to ultimate weight, and is the largest for crocodiles, followed by that of turtles. These facts explain why the precociality coefficient, sHbp—approximated by the ratio of weight at birth and weight at puberty at abundant food—decreases with ultimate weight. It is the smallest for crocodiles because of their large size and is smaller for turtles than for lizards and snakes. The sea turtles have a smaller sHbp than the rest of the turtles, linked to their large size and small offspring size. We link their small weight and age at birth to reducing risks on the beach. The maximum reserve capacity in both turtles and crocodiles clearly decreases with the precociality coefficient. This relationship has not been found that clearly in other taxa, not even in other reptiles, with the exception of the chondrichthyans. Among reptiles, crocodiles and sea turtles have a relatively large assimilation rate and a large reserve capacity.     

Anionic detergents in Mytilus Galloprovincialis of the gulf of Naples

The authors have investigated on the anionics detergents rate inside the Mytilus Galloprovincialis, used as animal-monitor of the environment state of a certain part of the Gulf of Naples. The data concerning 14 zones in which were drown mussels cultivated in the Gulf of Naples resumed in a specific list, shown an high concentration of above detergents.     

Molecular cloning of estrogen receptor alpha of the Nile crocodile

Estrogens are essential for normal reproductive activity in female and male vertebrates. In female reptiles, they are essential for ovarian differentiation during a critical developmental stage. To understand the molecular mechanisms of estrogen action in the Nile crocodile (Crocodylus niloticus), we have isolated cDNA encoding the estrogen receptor alpha (ERalpha) from the ovary. Degenerate PCR primers specific to ER were designed and used to amplify Nile crocodile cDNA from the ovary. The full-length Nile crocodile ERalpha cDNA was obtained using 5' and 3' rapid amplification cDNA ends (RACE). The deduced amino acid sequence of the Nile crocodile ERalpha showed high identity to the American alligator ERalpha (98%), caiman ER (98%), lizard ER (82%) and chicken ERalpha (92%), although phylogenetic analysis suggested profound differences in the rate of sequence evolution for vertebrate ER sequences. Expression of ERalpha was observed in the ovary and testis of juvenile Nile crocodiles. These data provide a novel tool allowing future studies examining the regulation and ontogenic expression of ERalpha in crocodiles and expands our knowledge of estrogen receptor evolution.     

Effects of Different Rearing Strategies and Ages on Levels of Natural Antibodies in Saliva of the Philippine Crocodile

The endemic Philippine crocodile(Crocodylus mindorensis) is a relatively small, critically endangered freshwater crocodile. In a head start program, crocodile hatchlings are caught in the wild, reared in captivity, and released back into the wild after two years. The current study aimed to determine optimal rearing strategies of Philippine crocodile hatchlings, including identification of possible diseases during rearing, and studying the effect of ages on natural antibody(NAb) levels. Thirty Philippine crocodiles were divided into two groups, half were reared with a hiding board, and half without the hiding board. Both groups received three different kinds of diets: meat, shrimp, or a combination of both. Saliva samples of the crocodiles were taken three times over a period of three months to test for NAb levels. Saliva samples were also taken from older crocodiles and crocodiles from different locations. NAb titres were compared to sheep red blood cells. Each time saliva samples were taken, a health check was done. The results showed that crocodiles would prefer the hiding board, and neither housing nor diet could affect the level of NAb titres in saliva. A positive correlation was found between NAb titres and body size, weight and age. Wild hatchlings had higher NAb titres than the hatchlings born in captivity, but the difference diminished with ageing. Five different diseases were found.