Body of evidence: forensic use of baseline health assessments to convict wildlife poachers

CONTEXT. Given the immense impact of wildlife trade, disease and repatriations on populations, health assessments can" "provide powerful forensic material to help convict wildlife poachers and minimise risks of releasing unhealthy wildlife." AIMS. We aimed to use reference ranges to assess the health of confiscated tortoises, to illustrate forensic application of these ranges, and to advance analyses for future applications." METHODS. We used analyses of variance (ANOVA) and covariance (ANCOVA), and composite indices, to compare wild and confiscate tortoise body condition, haematocrit and haemoglobin concentration of males and females of three tortoise species. Subsequently, we used multivariate statistics (e.g. discriminant analyses) to evaluate the relative importance of species, sex and group (wild or confiscate) on tortoise condition and haematology." KEY RESULTS. Our initial statistical tests demonstrated, at P < 0.05 to P < 0.0005, that confiscate body condition and haematology were compromised compared with that of wild tortoises. Subsequently, discriminant analyses strongly discriminated between most wild and confiscate groups (P < 0.0001), correctly classified individual health as wild or confiscate 80–90% of the time, indicated that species and sex effects were stronger than was the wild-confiscate category, and provided discriminant functions for use on other taxa and studies." CONCLUSIONS. The health assessments discriminated well between wild and confiscate tortoises. The results had considerable forensic value, being relevant, quickly generated using portable field equipment, reliable, accurate, easy to explain and convey in terms of likelihood in a court of law, synergistically consistent among variables and groups, a strong rebuttal to the poachers’ specific statements, and consistent with other types of evidence. Multivariate analyses were consistent with, and more prudent and powerful than, the original statistical analyses. Discriminant functions can be applied in future studies and on other chelonian species, and should be developed for other wildlife species." IMPLICATIONS. Reference ranges provide considerable value for forensics, diagnostics and treatment. Given the disease risks resulting from the massive scale of wildlife trade and release, reference ranges should be developed for more species."Web of Scienc

Sexual disparity in activity patterns and time budgets of angulate tortoises (Chersina angulata) on Dassen Island, South Africa

Behavioural frequencies and time budgets for male and female Chersina angulata were recorded in spring, September 2004. The daily activity of the population was 10.51 ± 0.42 h (mean ± CI), but individual males and females were in the open for 2.57 ± 1.12 h and 1.58 ± 1.44 h, respectively. Both sexes spent nearly 3.5 h per day basking with 90% of the basking time in the cover of sparse vegetation. Feeding and walking were the most frequent active behaviours. The activity pattern of the sexes differed between 10:00 and 12:00 in the morning when males spent more time out of cover on active behaviours, particularly feeding, than females did. The daily activity pattern of the population peaked between 10:00 and 12:00, reflecting the activity pattern of the more active sex, males. Females were out of cover, active, and feeding at higher temperatures than were males. The high temperatures  probably allowed  females to complete activities more efficiently, reducing their exposure time and  predation risk. Although fighting and mating represented small fractions of male time budgets, the extended physical presence through walking and feeding may help  males to establish dominance hierarchies and enhance mating success.Key words: activity pattern, behaviour, temperature, thread-trailing, time budget, tortoise

Season, sex and age variation in the haematology and body condition of geometric tortoises Psammobates geometricus

Body condition and haematological indices provide powerful information when assessing wildlife health. Reference intervals for these indices can facilitate wildlife management, and would benefit initiatives to save the Critically Endangered geometric tortoise (Psammobates geometricus). We collected data from 126 geometric tortoises to establish baseline values reflecting variation over four seasons (spring 2000 to winter 2001) and among three groups (female, male and juvenile). We measured body condition index (BCI; mass to shell volume), blood urea nitrogen (BUN), plasma chloride, packed cell volume (PCV), haemoglobin concentration (Hb) and red blood cell count (RBC), and used PCV, Hb and RBC to calculate erythrocyte indices. BCI correlated poorly with haematological measures but had a strong inverse relationship with BUN. BCI did not vary among groups, but all groups had low condition indices in autumn, the end of the dry season. High BUN and chloride values in autumn indicate dehydration, particularly in males. Males had the highest PCV, Hb and RBC values, especially during summer and autumn when they moved long distances, likely pursuing mates. Female and juvenile indices were similar, except that female Hb was higher than juvenile Hb, possibly to meet female energy needs associated with their large size and reproductive metabolism. Low Hb levels in winter coincided with low temperatures and reduced movements. Our results illustrate how intrinsic and extrinsic factors influence the physiology of geometric tortoises and provide reference intervals to monitor their health.Keywords: blood urea nitrogen, erythrocyte indices, haemoglobin, packed cell volume, red blood cell count, reference interval

Tick infestations in the Namaqualand speckled padloper, Homopus signatus signatus (Gmelin, 1789)

Many terrestrial chelonians are parasitized by ticks, but we have a poor   understanding of what determines tick infestations on chelonian hosts. We counted ticks on Homopus signatus signatus during each spring in the years 2001–2004, and evaluated tick frequencies in relation to tortoise anatomy, climate and  microhabitat. Tortoises hosted Ornithodoros compactus and O. savignyi, and ticks seemed to prefer the hindlimbs, avoid the shell, and use the forelimbs and neck in intermediate frequencies. The number of ticks on the neck and forelimbs did not differ among males, females and juveniles, but for the hindlimbs and all body parts, males and females usually had similar tick numbers and adults often had more ticks than juveniles. The number of ticks on the hindlimbs correlated with the body size of male and female tortoises, whereas the number of ticks on the forelimbs correlated with juvenile body size. Males and females had similar incidences of ticks despite sexual dimorphism in body size (female size &gt; male size), and this may be due to the relatively large shell openings (soft skin exposure) of males compared to females. Body condition and microhabitat had no effect on the number of ticks. It is unclear why tick numbers on H. s. signatus increased in dry years. The adverse effects of drought on mammals may have caused ticks to switch from mammals to tortoises when preferred hosts were no longer available.Keywords: host switching, morphology, Ornithodoros, parasite, sexual dimorphism, tortoise

Leaf biomechanics as a potential tool to predict feeding preferences of the geometric tortoise Psammobates geometricus

Food and non food plant characteristics were studied for the geometric tortoise,  Psammobates geometricus, to test the hypothesis that feeding preferences in  tortoises may be influenced by the mechanical properties of plant leaves. Twelve focal feeding observations made between 8 October and 31 October 2002 were synthesized with literature reports to develop species lists of food and non food grasses and geophytes in renosterveld habitat. Failure load and tensile strength were determined in the field for leaves of food and non food plants that were spatially available to the tortoises and present in relative abundance during the course of the study. Leaves of geophyte food plants were fleshy and succulent with a low failure load and tensile strength. Leaves of food plant grasses had significantly higher failure loads and tensile strengths compared to leaves of food plant geophytes. In non food plants there was no signifi cant difference in failure load between grasses and geophytes, but tensile strength was signifi cantly higher in the grasses. Non food plant grasses and geophytes overall had significantly higher failure load and tensile strength values than did food plants. Two non food plants that overlapped in mechanical strength to the food plants either have toxic/unpalatable chemicals in high amounts or are recent invasive species to the renosterveld. Thus, these studies support the hypothesis that leaf biomechanical properties may be an important factor in determining the diet of the geometric tortoise and perhaps tortoises in general.Key words: biomechanics, failure load, herbivore, Psammobates geometricus, tensile strength