Komodo Research Articles

Comparison of growth and nutritional status of juvenile Komodo monitors (Varanus komodoensis) maintained on rodent or poultry‐based diets

AbstractNutrition and growth data were collected on six juvenile Komodo monitors (Varanus komodoensis) over 20 months. The animals were captive‐bred from two separate clutches, laid 6 months apart. Three animals were fed a rodent diet, and the other three were fed a poultry‐based diet. The animals were all weighed and measured weekly. Blood samples were collected monthly. Blood samples were analyzed for sodium (Na), potassium (K), calcium (Ca), phosphorus (P), magnesium (Mg), 25‐OH‐D, and cholesterol. Significant differences (P<0.05) were observed in dry matter intake (DMI) (1.12 vs. 0.90 %BW) and gross energy intake (GEI) (182.3 vs. 143.0 kcal GE/d), between rodent and poultry‐based diets, respectively. However, there were no differences in growth (average daily gain=6.13 vs. 6.33 g BW/d) between the two dietary treatments. Blood Na, K, Ca, P, Mg, and 25‐OH‐D concentrations were similar across treatments, while cholesterol levels were higher in the animals maintained on the rodent‐based diet. Zoo Biol 23:239–252, 2004. © 2004 Wiley‐Liss, Inc.

Distribution, use and selection of nest type by Komodo Dragons

We report the abundance, patterns of distribution and physical characteristics of Komodo dragon (Varanus komodoensis) nests on Komodo Island in Indonesia. A total of 46 Komodo dragon nesting sites were identified, of these 26 nests were considered active for the 2002/2003 season. The distribution of nests coincided with large coastal valleys in northern Komodo Island. There was a significant preference by breeding females to utilize the mound nests (61%) over both open hillside (19.5%) and ground nests (19.5%). Further, within these mound nests, females discriminated for nests based on habitat characteristics, especially sunlight exposure. The main implications for management and conservation drawn from this study is that there is a small number of females nesting annually on the largest island within Komodo National Park. Further, continuation of nesting surveys could provide a cost effective accurate way to gather important long term demographic information on this species.

Apocalypse soon?

Apocalypse soon?

Aerobic salivary bacteria in wild and captive Komodo dragons.

During the months of November 1996, August 1997, and March 1998, saliva and plasma samples were collected for isolation of aerobic bacteria from 26 wild and 13 captive Komodo dragons (Varanus komodoensis). Twenty-eight Gram-negative and 29 Gram-positive species of bacteria were isolated from the saliva of the 39 Komodo dragons. A greater number of wild than captive dragons were positive for both Gram-negative and Gram-positive bacteria. The average number of bacterial species within the saliva of wild dragons was 46% greater than for captive dragons. While Escherichia coli was the most common bacterium isolated from the saliva of wild dragons, this species was not present in captive dragons. The most common bacteria isolated from the saliva of captive dragons were Staphylococcus capitis and Staphylococcus capitis and Staphylococcus caseolyticus, neither of which were found in wild dragons. High mortality was seen among mice injected with saliva from wild dragons and the only bacterium isolated from the blood of dying mice was Pasteurella multocida. A competitive inhibition enzyme-linked immunosorbent assay revealed the presence of anti-Pasteurella antibody in the plasma of Komodo dragons. Four species of bacteria isolated from dragon saliva showed resistance to one or more of 16 antimicrobics tested. The wide variety of bacteria demonstrated in the saliva of the Komodo dragon in this study, at least one species of which was highly lethal in mice and 54 species of which are known pathogens, support the observation that wounds inflicted by this animal are often associated with sepsis and subsequent bacteremia in prey animals.

Knowledge Forum: altering the relationship between students and scientific knowledge

This paper explores the use of Knowledge Forum, a networked computer program designed to support knowledge building communication and to foster thinking and learning skills. The paper focuses on a Grade 5/6 classroom and looks at how students view scientific knowledge and what it means to learn science. A shift in pedagogy, along with the learning opportunities afforded by the communal database, impacted the learning environment and created changes in the structure of the learning activities, the ‘rules of the game’ of science and the sequencing of the curriculum. Specifically, the paper examines the knowledge transforming discourse that occurred both on and off the database as children worked to understand the evolution of the Komodo Dragon during an investigation of islands and island biogeography.

Monitoring of Plasma 25-Hydroxyvitamin D Concentrations in Two Komodo Dragons, Varanus komodoensis: A Case Study

ABSTRACT Like many basking lizard species, the Komodo dragon, Varanus komodoensis, is believed to require exposure to ultraviolet light of the appropriate wavelength to allow for vitamin D3 synthesis and calcium absorption and homeostasis. Serum or plasma 25-hydroxyvitamin D (25-OH-D) concentration is considered the most useful assessment of overall vitamin D status in humans and animals. This case study describes the trends in plasma 25-OH-D in two captive Komodo dragons housed both indoors and outdoors in Louisville, KY over a 2.5-yr period. Data suggest that ultraviolet light exposure is critical to allow Komodo dragons to reach plasma 25-OH-D levels comparable to those levels reported in both wild dragons, and captive dragons offered daily sun exposure. Additionally, it appears that in temperate climates, approximately 150 d of sun exposure combined with moderate amounts of dietary vitamin D3 may be adequate for Komodo dragons to develop and maintain appropriate circulating levels of 25-OH-D throughou...

Location of fruit using only airborne odor cues by a lizard

Although squamate reptiles are known to locate conspecifics by scent-trailing and to locate and identify prey by tongue-flicking substrates, an ability to locate food using only airborne cues has previously only been suspected based on observations that dead animals can be used as bait for Komodo dragons and that some nocturnal geckos aggregate on flowers. We conducted a simple field test of the ability of the omnivorous lizard Podarcis lilfordi to find fruit hidden under opaque cups. When a board having two identical cups spaced 1 m apart, one empty and the other hiding a freshly cut piece of apricot, was placed in the habitat, lizards first contacted the cup hiding fruit at well above chance frequency. Upon contact with a cup, lizards were significantly more likely to stay next to the cup, tongue-flick at high rates, climb the cup, and attempt to bite the cup if it hid a piece of apricot. The ability to follow a concentration gradient of airborne volatile chemicals to its source is very likely mediated by olfaction, but participation by or primacy of vomerolfaction cannot be excluded.

Feeding dragons in Komodo National Park: a tourism tool with conservation complications

AbstractLarge carnivores are key visitor attractions in protected areas, but are difficult to see. Thus, supplementary feeding is sometimes used to attract them to viewing sites. Such intervention is contentious but its effects have rarely been examined. This paper analyses a case study of supplementary feeding in Komodo National Park, Indonesia. Using data from daily and annual Komodo dragon censuses, feeding records and financial accounts, the effects of feeding and its cessation on dragon numbers, tourist viewing opportunities and local community benefits were examined. Regular feeding caused dragon numbers to increase at the feeding site, but not year‐round. Cessation of feeding caused numbers to decline again to natural levels. However, tourists were less likely to see dragons at the feeding site after cessation, and local community revenues declined with the loss of a market for goats. Solutions lie in finding less intrusive means for tourists to view dragons, and enabling local people to become involved in tourism through training, recruitment and the development of alternative markets.

Blood values in wild and captive Komodo dragons (Varanus komodoensis).

The Komodo dragon (Varanus komodoensis) is the largest living lizard and occupies a range smaller than that of any other large carnivore in the world. Samples from 33 free-ranging animals at five localities in Komodo National Park, Indonesia were evaluated to assess underlying health problems. To build a comparative database, samples from 44 Komodo dragons in both Indonesian and U.S. zoos were also analyzed. Tests performed included complete blood counts, clinical chemistry profiles, vitamin A, D(3), and E analyses, mineral levels, and screening for chlorinated pesticides or other toxins in wild specimens. Blood samples from wild dragons were positive for hemogregarines, whereas captive specimens were all negative. Total white blood cell counts were consistently higher in captive Komodo dragons than in wild specimens. Reference intervals were established for some chemistry analytes, and values obtained from different groups were compared. Vitamin A and E ranges were established. Vitamin D(3) levels were significantly different in Komodo dragons kept in captive, indoor exhibits versus those with daily ultraviolet-B exposure, whether captive or wild specimens. Corrective measures such as ultraviolet-permeable skylights, direct sunlight exposure, and self-ballasted mercury vapor ultraviolet lamps increased vitamin D(3) concentrations in four dragons to levels comparable with wild specimens. Toxicology results were negative except for background-level chlorinated pesticide residues. The results indicate no notable medical, nutritional, or toxic problems in the wild Komodo dragon population. Problems in captive specimens may relate to, and can be corrected by, husbandry measures such as regular ultraviolet-B exposure. Zoo Biol 19:495-509, 2000. Copyright 2000 Wiley-Liss, Inc.

Taronga's komodo dragon recovering from cataract op

Australian Veterinary JournalVolume 78, Issue 1 p. 10-10 Free Access Taronga's komodo dragon recovering from cataract op First published: 10 March 2008 https://doi.org/10.1111/j.1751-0813.2000.tb10341.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume78, Issue1January 2000Pages 10-10 RelatedInformation

Genetic structure and gene flow among Komodo dragon populations inferred by microsatellite loci analysis.

A general concern for the conservation of endangered species is the maintenance of genetic variation within populations, particularly when they become isolated and reduced in size. Estimates of gene flow and effective population size are therefore important for any conservation initiative directed to the long-term persistence of a species in its natural habitat. In the present study, 10 microsatellite loci were used to assess the level of genetic variability among populations of the Komodo dragon Varanus komodoensis. Effective population size was calculated and gene flow estimates were compared with palaeogeographic data in order to assess the degree of vulnerability of four island populations. Rinca and Flores, currently separated by an isthmus of about 200 m, retained a high level of genetic diversity and showed a high degree of genetic similarity, with gene flow values close to one migrant per generation. The island of Komodo showed by far the highest levels of genetic divergence, and its allelic distinctiveness was considered of great importance in the maintenance of genetic variability within the species. A lack of distinct alleles and low levels of gene flow and genetic variability were found for the small population of Gili Motang island, which was identified as vulnerable to stochastic threats. Our results are potentially important for both the short- and long-term management of the Komodo dragon, and are critical in view of future re-introduction or augmentation in areas where the species is now extinct or depleted.

Genetic divergence and units for conservation in the Komodo dragon Varanus komodoensis

In the past decade much attention has focused on the role that genetics can play in the formation of management strategies in conservation. Here, we describe genetic diversity in the world's largest lizard, the Komodo dragon (Varanus komodoensis), examining the evolutionary relationships and population genetic history of the four islands in south-east Indonesia, which form the vast majority of its range. We identify distinct genetic groups for conservation. The population on the island of Komodo shows by far the largest values of genetic divergence and is proposed that it should be a separate conservation management unit. Other populations, surviving either on small islands with substantially reduced genetic variability, or in isolated patches, are identified as particularly vulnerable to stochastic threats and habitat loss. Our results provide an example of how data defining intraspecific levels of genetic divergence can provide information to help management plans, ensure the maintenance of genetic variability across populations and identify evolutionary potential within endangered species.

An outbreak of salmonellosis among children attending a reptile exhibit at a zoo

Objective: In January 1996, an outbreak of diarrhea caused by Salmonella Enteritidis occurred in children attending a Komodo dragon exhibit at a metropolitan zoo. We sought to determine the extent of the outbreak and mode of transmission. Study design: A case-control study was conducted. Controls were randomly selected from zoo membership lists and matched to patients by age group and date of exhibit visit. Results: Of 65 patients identified, 39 had confirmed and 26 had suspected cases. The median age was 7 years (range, 3 months to 48 years); 55% were male, and 56% had bloody diarrhea. Twenty-six patients and 49 controls were enrolled in the case-control study. No patients and two (4%) controls reported touching a dragon; however, 83% of patients but only 52% of controls touched the wooden barrier that surrounded the dragon pen (odds ratio = 4.0, 95% CI 1.2 to 13.9). Washing hands at the zoo after visiting the dragons was highly protective (OR = 0.14, 95% CI 0.03 to 0.7). Cultures from the patients, one dragon, and the exhibit barriers yielded Salmonella Enteritidis, phage type 8. On the basis of an attack rate of 4.3% among exhibit attendees under 13 years old on whom data were collected, we estimate that 315 additional cases of salmonellosis occurred among visitors in this age group. Conclusion: This large outbreak demonstrates the importance of environmental contamination in the transmission of Salmonella from reptiles, and the protective value of hand washing. Recommendations regarding reptile exhibits and reptilian pets should emphasize this indirect route. (J Pediatr 1998;132:802-7)

The amino acid sequences of two alpha chains of hemoglobins from Komodo dragon Varanus komodoensis and phylogenetic relationships of amniotes.

To elucidate phylogenetic relationships among amniotes and the evolution of alpha globins, hemoglobins were analyzed from the Komodo dragon (Komodo monitor lizard) Varanus komodoensis, the world's largest extant lizard, inhabiting Komodo Islands, Indonesia. Four unique globin chains (alpha A, alpha D, beta B, and beta C) were isolated in an equal molar ratio by high performance liquid chromatography from the hemolysate. The amino acid sequences of two alpha chains were determined. The alpha D chain has a glutamine at E7 as does an alpha chain of a snake, Liophis miliaris, but the alpha A chain has a histidine at E7 like the majority of hemoglobins. Phylogenetic analyses of 19 globins including two alpha chains of Komodo dragon and ones from representative amniotes showed the following results: (1) The a chains of squamates (snakes and lizards), which have a glutamine at E7, are clustered with the embryonic alpha globin family, which typically includes the alpha D chain from birds; (2) birds form a sister group with other reptiles but not with mammals; (3) the genes for embryonic and adult types of alpha globins were possibly produced by duplication of the ancestral alpha gene before ancestral amniotes diverged, indicating that each of the present amniotes might carry descendants of the two types of alpha globin genes; (4) squamates first split off from the ancestor of other reptiles and birds.

Microsatellite Libraries Enriched for Several Microsatellite Sequences in Plants

Microsatellite Libraries Enriched for Several Microsatellite Sequences in Plants

Predicting the gender of subadult Komodo dragons (Varanus komodoensis) using two-dimensional ultrasound imaging and plasma testosterone concentration

Six yearling Komodo dragons (Varanus komodoensis) underwent ultrasound examinations every three months over a nine-month period to assess the value of two-dimensional ultrasound imaging technology for the purpose of determining gender in this highly monomorphic species. Beginning at an age of 28 months, ovarian structures could be imaged, allowing a prediction of gender based on the presence or absence of ovarian follicles. Simultaneously, plasma testosterone concentration was measured monthly on each individual during the study period. Beginning at an age of 24 months, putative males had consistently elevated plasma testosterone values that were ∼40–60 times greater than those of putative females. In a blind comparison, predictions of gender based on plasma testosterone values matched the prediction of sex based on ultrasound imaging for all six individuals. The results indicate that measurements of circulating testosterone and two-dimensional ultrasound imaging together appear useful in the noninvasive determination of gender in juvenile V. komodoensis at just over two years of age. © 1996 Wiley-Liss, Inc.

Oxygen Uptake by Komodo Dragon (Varanus komodoensis) Eggs: The Energetics of Prolonged Development in a Reptile

Oxygen consumption was measured during incubation in the eggs of the Komodo dragon (Varanus komodoensis), a reptile that exhibits prolonged embryonic development. Oxygen consumption of eggs (mean mass 175 g) showed a sigmoidal pattern over the course of an incubation period, averaging 235.6 d at 29°C. The rate of oxygen consumption during the plateau prior to hatching averaged 151.1 mL/d. The incubation time was 210% greater and the peak oxygen consumption 53.2% less than predicted by existing allometric equations. Analysis of incubation time data indicates that the Komodo dragon is not unique in having prolonged incubation times relative to those of previously studied reptiles that do not undergo diapause. The cost of development in dragons averaged 329.4 kJ (1.88 kJ/g egg mass), which is significantly higher than predicted. These results are consistent with those predicted from models of developmental energetics based on avian species.

The Serrated Teeth of Tyrannosaurid Dinosaurs, and Biting Structures in Other Animals

The function of serrated teeth is analyzed by experimental comparison with the action of artificially made steel blades. Serrated blades cut compliant materials with a grip-and-rip mechanism, whereas smooth, sharp blades cut by concentrating a large downward force on a tiny area.Tyrannosaurid teeth from the Cretaceous Judith River Formation bear rows of serrations that have thick, rounded enamel caps, gripping slots between neighboring serrations, thick enamel bodies inside the teeth underneath the gripping slots, and a root beneath each serration. In contrast, the carnivorous dinosaurTroodonhas teeth with exposed pointed serrations, thin enamel, and possibly serration roots.Serrations on the teeth ofTroodonand the fossil sharkCarcharodon,cut compliant materials in the same way as a serrated hacksaw blade. In contrast, the cutting action of tyrannosaurid teeth most closely resembles that of a dull smooth blade. The spaces between the serrations act as minute frictional vises that grip and hold meat fibers; chambers between neighboring serrations receive and retain small fragments of meat, and inevitably would have acted as havens where bacteria could be stored. These spaces may therefore have led to infections in wounds, analogous to those inflicted by the living Komodo dragon or ora. By analogy, the hunting and feeding behavior of tyrannosaurs may have resembled that of the ora.Serrations and slots are widely distributed among cutting devices in the natural world, and many of these deserve further study. For example, the carnassial teeth of mammalian carnivores cut by a combination of static force at the cutting edge, a crushing or scissoring action at the advancing junction between upper and lower teeth, and by lateral gripping and compression in a slot, like that seen on a much smaller scale in tyrannosaurid serrations. Mammalian teeth operate well only when deployed with sophisticated control over jaw movement, however, and the fine neural control necessary to operate them may have formed the basis for the later development of intelligence in mammals.Previously, being interested in mammals was largely a matter of being interested in teeth, whereas being interested in reptiles was largely a matter of being interested in everything but teeth. I suggest that the teeth of at least some reptiles are as rich in information as the teeth of any mammals.

The thermal physiology of the Dinosauria: direct evidence from oxygen isotopes

The thermal physiology of extinct reptiles has been a hotly debated topic for the last two decades, with no direct evidence available to help solve the debate. Oxygen isotopes are fractionated with respect to temperature between an animal's body water and bone phosphate, thus providing avenues for deriving the first direct evidence of dinosaur thermal physiology.Multiple samples from both cortical and cancellous areas from individual bones were sampled in order to determine the heterogeneity of δ18O values within single bones. Bones from both the body core (ribs and vertebrae) and the extremities (limbs and caudal vertebrae) of known individual dinosaurs were sampled in this method. This allows for a comparison of isotopic heterogeneity from bones of all body regions. In ectothermic heterotherms or mass homeotherms the δ18O values from the extremities are expected to generally be heavier than those from ribs or dorsal vertebrae. It is also expected that there would be a greater degree of heterogeneity of δ18O values from bones in the extremities than those in the body core for these individuals. This relationship would result from the greater degree of heat loss from the extremities than body cores due to greater surface areas and distance from the heart. This relationship has been seen in analyses on bones from the modern Varanus komodoensis. On the other hand, true endothermic homeotherms should show a very narrow range of hetergeneity of δ18O values both within individual bones and between bones within single individuals as seen in modern mammals.Dinosaurs analyzed indicate isotopic heterogeneities within individual bones intermediate between modern mammals and Varanus, with the Tyrannosaurus showing the greatest isotopic variability. However, this isotopic heterogeneity is relatively small and is not significantly different for bones from the body core and extremities. This indicates that heterogeneity of the δ18O values is most likely the result of variations in drinking water δ18O values throughout an individual's lifetime rather than daily or seasonal variations in body temperatures.

A new method for the determination of the δ18O composition of bone phosphate: applications to the thermal physiology of vertebrates

A new method for the preparation of bone samples for δ18O-PO4 analysis has been developed. The phosphate from bone samples is separated and purified using ion exchange chromatography, and then precipitated as silver phosphate using the Firsching method. O2 is then extracted by reaction with bromine pentafluoride and converted to CO2 for isotopic analysis. Advantages of the silver phosphate technique over the bismuth phosphate technique are (1) the simplicity of the method, (2) silver phosphate is not hygroscopic so atmospheric water is not an oxygen contaminate, and (3) very small samples (2 mg to 10 mg) can be analyzed with an increase of precision compared to previous techniques. Iron and silica oxides added to Ag3PO4 standards produce no offset, which suggests that this new technique is not sensitive to interferences from cements commonly found in fossil bone material. Analyses have been performed on standards ranging in size from 30 mg to 2 mg with a σ1 of ± 0.05 per mil.The δ18O-PO4 compositional pattern of the bones of modern vertebrates have been analyzed to provide a base for the interpretation of the δ18O-PO4 pattern of fossil vertebrates. The average %PO4 in modern mammals and reptiles is approximately 15% with a σ1 of 2-3 %. The average %PO4 of fossil reptiles range from 10 to 25% with σ1 variations of up to 10%. The %PO4 variation can be related to cementation of void spaces in the bone material. XRD analysis reveals that calcite, dolomite, ankerite, and silica cements are commonly present. FTIR (Fourier Transform Infrared Spectroscopy) yields low indices calculated according to the formula of Shemesh, 1990 [GCA 54(9):2433]. Thin sections of the fossil bone material show detailed structures. All this evidence suggests that the fossil bone δ18O-PO4 composition is pristine and not altered by diagenesis. The total δ18O-PO4 σ1 variation of 10 or more skeletal elements analyzed for each individual specimen varies from 0.1 per mil for a domestic cow (Bos) to 0.8 per mil for a Komodo dragon (Varanus). Variations in between appear to be related to thermal physiology and variations in drinking water δ18O due to seasonality or migration.