Minutes of the Discussions Fig. 5. Some participants of the specialist workshop in the REPTILIUM. while adults preferred spots in the current. Fifteen specimens were caught within just half an hour at night. Juveniles should not be housed together as this may raise stress to lethal levels. One keeper reported on the successful raising of 20 babies in individual water tanks of 60 × 30 cm floor space (water level ca. 10 cm); the presence of aquatic vegetation as cover proved crucial as the baby turtles would otherwise be in a state of constant panic. Following the experiences of one keeper, captive Chelus fimbriata are usually obese, which is a result of excessive feeding. Juveniles may be up to 160 % heavier than matamatas of the same age group in the wild; free-ranging specimens acquire more food during the dry season (in the wild: 25 cm in carapace length = 1 kg body mass). One participant of the workshop stated that his matamatas would consume just about anything when they were hungry: chicks, rats, etc., but they would have a predilection for fish and ignore other foods if fish were available. The specimens in the care of another keeper did not accept chicks, but also took tadpoles next to fish; if fish and tadpoles were offered at the same time, the Chelus fimbriata would specifically target the tadpoles; the turtles would also take food that was offered from forceps. His turtles share their aquaterrarium with some cichlid fish of the genus Tilapia, which would be predated upon while guarding their clutches. If the matamatas were fed generously, they would leave the fish alone, but if they received less food they increased the predatory pressures on the cichlids. The possibility of deficiency syndromes was pointed out if defrosted frozen fish was used as a staple diet (thiaminase). Another keeper of matamatas reported that his specimens would consume pieces of beef heart, for example, that were left lying on the bottom of the tank at night. Another participant added his mixed 76 RADIATA 17 (3), 2008
Minutes of the Discussions experiences in this respect: some specimens would consume everything that was offered them, while others would take mice, but later regurgitate them. Subject: The Genus Acanthochelys Acanthochelys spixii is the species most readily available for captive keeping; it is rather easy to keep and usually feeds readily. Its propagation is still fraught with problems, however: various keepers managed to recover fertile eggs, but encountered problems when the babies tried to hatch. The turtles can be fed, for example, with fresh fish and baby mice. It was stated that they would occasionally catch live guppies even though they would not actively pursue these. The hunting technique of suction snapping was observed. Numerous oviposition events did not lead to babies hatching: there was not embryonic development. A likely reason is the absence of a cool phase during the incubation period. Winter temperatures in Buenos Aires may easily drop to freezing point, which is the time when clutches are incubating in nature. One keeper reported on inserting a cool phase during incubation, which resulted in the successful development of the eggs. There appears to be some intraspecific aggression: one keeper mentioned a female that was aggressive towards a male and injured him even though the pair was housed in a spacious outdoor pond. This was confirmed by another observation of a female killing one male and behaving aggressively towards another. Subject: The Genus Podocnemis Representatives of this genus are rarely bred in captivity. Successful propagation, partly with very high hatching rates, was reported for Podocnemis unifilis and Podocnemis vogli. Captive husbandry is quite limited to the keeping of Podocnemis unifilis, Podocnemis vogli and Podocnemis expansa. Only one keeper is known to keep Podocnemis sextuberculata in Europe. Husbandry of these turtles entails Fig. 6. Some participants of the specialist workshop in the REPTILIUM. RADIATA 17 (3), 2008 77
