A true facultative carnivore? Effects of replacing ground chicken carcasses with soybean meal on the growth of captive broad-snouted caiman (Caiman latirostris) and its economics implications.

A specific diet for broad-snouted caiman, Caiman latirostris has not been designed despite the value of farm-raised caiman as an aquaculture product. To fill this gap, the objectives of this study were to evaluate the performance dietary replacement of ground chicken carcasses by of soybean meal (SM) as diet complement for C. latirostris. We conducted a 3-month growth trial to determine effects of graded levels of dietary SM on caiman growth as measured by increase in body length, body weight gain, food consumption (FC) and food conversion rate (FCR). Forty-eight hatchling caimans were fed with diets, composed primarily of practical feed ingredients, with 0, 25, or 40% dietary SM. Diets were fed three times per week for 90 days under temperature controlled. Body lengths and body weights were measured at 30-day intervals, and FC samples were taken between the 31-60-day interval. The results of this study indicate that the inclusion of SM in the diet of C. latirostris at levels of 25% increases in body length, body weight gain, FC and improve the FCR indicated that a concentration of 25% dietary SM (as fed) was adequate for growth of caimans under the conditions of this study. Results suggest that SM have a real nutritional contribution in the diet of broad-snouted caiman and can be used as an ingredient of the diet of the crocodilians raised in captivity, reducing production costs for sustainable use and conservation programs of this species.

Translocation, genetic structure and homing ability confirm geographic barriers disrupt saltwater crocodile movement and dispersal.

Translocated saltwater crocodiles (Crocodylus porosus) in the Northern Territory (NT) of Australia often return to their original capture sites, which complicates management interventions aimed at reducing human-crocodile conflict. We examined the spatial events implicated in this homing ability, using ARGOS satellite tracking devices. Five large male C. porosus (3.03 m to 4.02 m TL) were shifted and released 100-320 km from their capture sites, and 3 additional ones (3.67 m to 4.23 m TL) were released at their site of capture as controls. Translocated crocodiles were more mobile than the controls, and moved at sea in the direction of their original capture site. However, they were unable or unwilling to swim around a geographic structure, Cobourg Peninsula, which prevented homing being achieved in all five cases. Two control crocodiles remained near their capture sites, but one, after the first year, made a 900km journey for six months, before returning to its original capture and release site. Genetic analysis of tissue samples from nests across the NT coast demonstrated significant genetic structure across the coast, and confirmed that Cobourg Peninsula contributes to genetic differentiation among populations along the NT coast. These results provide new insights into C. porosus movements, which have management significance for the maintenance of public safety.

Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection.

Since 2006, 3 new disease syndromes have emerged in farmed saltwater crocodiles (Crocodylus porosus) in the Northern Territory of Australia. We describe the syndromes through a retrospective study of laboratory findings from 187 diagnostic cases submitted to Berrimah Veterinary Laboratories between 2005 and 2014. The first syndrome was characterized by conjunctivitis and/or pharyngitis (CP), primarily in hatchlings. Herpesviruses were isolated in primary crocodile cell culture, or were detected by PCR directly from conjunctiva or pharyngeal tissue, in 21 of 39 cases of CP (54%), compared with 9 of 64 crocodiles without the syndrome (14%, p < 0.0001). Chlamydiaceae were detected by PCR in conjunctiva or pharyngeal tissue of 55% of 29 CP cases tested, and of these, 81% also contained herpesvirus. The second syndrome occurred in juveniles and growers exhibiting poor growth, and was characterized histologically by systemic lymphoid proliferation and nonsuppurative encephalitis (SLPE). Herpesviruses were isolated or detected by PCR from at least 1 internal organ in 31 of 33 SLPE cases (94%) compared with 5 of 95 crocodiles without the syndrome (5%, p < 0.0001). The third syndrome, characterized by multifocal lymphohistiocytic infiltration of the dermis (LNS), occurred in 6 harvest-sized crocodiles. Herpesviruses were isolated from at least 1 skin lesion in 4 of these 6 cases. Although our study revealed strong associations between herpesvirus and the CP and SLPE syndromes, the precise nature of the role of herpesvirus, along with the pathogenesis and epidemiology of the syndromes, requires further investigation.

Dead or Alive? Factors Affecting the Survival of Victims during Attacks by Saltwater Crocodiles (Crocodylus porosus) in Australia.

Conflicts between humans and crocodilians are a widespread conservation challenge and the number of crocodile attacks is increasing worldwide. We identified the factors that most effectively decide whether a victim is injured or killed in a crocodile attack by fitting generalized linear models to a 42-year dataset of 87 attacks (27 fatal and 60 non-fatal) by saltwater crocodiles (Crocodylus porosus) in Australia. The models showed that the most influential factors were the difference in body mass between crocodile and victim, and the position of victim in relation to the water at the time of an attack. In-water position (for diving, swimming, and wading) had a higher risk than on-water (boating) or on-land (fishing, and hunting near the water's edge) positions. In the in-water position a 75 kg person would have a relatively high probability of survival (0.81) if attacked by a 300 cm crocodile, but the probability becomes much lower (0.17) with a 400 cm crocodile. If attacked by a crocodile larger than 450 cm, the survival probability would be extremely low (<0.05) regardless of the victim's size. These results indicate that the main cause of death during a crocodile attack is drowning and larger crocodiles can drag a victim more easily into deeper water. A higher risk associated with a larger crocodile in relation to victim's size is highlighted by children's vulnerability to fatal attacks. Since the first recently recorded fatal attack involving a child in 2006, six out of nine fatal attacks (66.7%) involved children, and the average body size of crocodiles responsible for these fatal attacks was considerably smaller (384 cm, 223 kg) than that of crocodiles that killed adults (450 cm, 324 kg) during the same period (2006-2014). These results suggest that culling programs targeting larger crocodiles may not be an effective management option to improve safety for children.

Crocodile attack in Australia: an analysis of its incidence and review of the pathology and management of crocodilian attacks in general.

Crocodilians represent one of the oldest constant animal lineages on the planet, in no small part due to their formidable array of predatory adaptations. As both human and crocodilian populations expand, they increasingly encroach on each others' territories, bringing morbidity and mortality to both populations. In this article, the medical and herpetologic literature pertaining to injuries caused by crocodilians is reviewed, and the patterns of saltwater crocodile attacks in Australia from 1971 to 2004 are analyzed. In this review, we examine the features of crocodilians that contribute to explaining their evolutionary success, as well as the potential hazard they pose to humans. Only by understanding their capabilities is it possible to mitigate the potential threat to life and limb.