Herbert Meier & Ingo Schaefer Figs. 2. Aquaterrarium for the captive keeping of Chelus fimbriata. Problems All considered, it is always flaws in husbandry conditions that result in the death of these animals. The following paragraphs are intended to encourage taking a critical and objective look at how these animals are kept. Space requirements A grave fault marring older descriptions of husbandry conditions (e.g., Rogner 1996) concerns the recommended size of the required tank and water level. Even the legally binding minimum requirements for housing terrarium animals issued by the German Bundesministerium für Ernährung, Landwirtschaft und Forsten (1997) are grossly undersized. The latter suppose that an adult pair with carapace lengths of 30 cm each can be adequately accommodated in a tank with a floor space of just 90 × 45 cm and a water level of less than 20 cm. This ignores the fact that animals with a carapace length of 30 cm have total lengths of nearly 60 cm – which is substantially more than the prescribed width of the tank! The reason for underestimating tank sizes is mainly that it is generally assumed that matamatas would not or hardly ever move. Besides the fact that this would indeed be hardly possible in a tank of the mentioned dimensions, it is also untrue. Given enough space, the turtles will be surprisingly active and also swim about if the water is just deep enough for doing so. Bottom substrate Various authors (e.g., Rogner 1996) recommend using sand as a bottom substrate. This corresponds to observations made in the wild, where almost all specimens have been found buried in sand. These specimens were without exception juveniles to subadults. Adult specimens could at that time of the year only be found in the current near the middle of the river (Meier & Schaefer 2003a, b). 20 RADIATA 17 (3), 2008
The Matamata, Chelus fimbriata Figs. 3. Aquaterrarium for the captive keeping of Chelus fimbriata. The two present authors do without a bottom substrate for reasons of hygiene, however, and this absence of a ground cover does not produce perceivable signs of stress. Schaefer (1986) used to keep a pair of adults in a tank measuring 2.70 × 0.70 m with a water level of 30 cm and under artificial light. Meier has been accommodating a group of 6.2 adult Chelus fimbriata in a basin covering a surface of 10 m², with a water depth of 60 cm (6,000 l of water), with natural daylight illuminating the installation. All turtles are active during the morning and evening hours and can often be seen swimming about in their artificial pond. Water temperatures are about the same with both authors, ranging around 24 °C. Finds in the wild demonstrate that even juvenile specimens prefer relatively deep water. Matamatas of just 10 cm in length were located buried in the sand in water 15 to 30 cm deep. At another locality, two 6 cm-long, few weekold babies were discovered at a water depth of about 40 cm (Meier & Schaefer 2003a, b). Structure of an aquaterrarium Chelus fimbriata is often thought of as highly susceptible to stress. Given a suitably sized and structured tank to live in, this notion will prove unfounded, however. Important features of a proper tank include that shaded resting places are available and that there is enough space for movement. Some individuals prefer to sleep in a zone of shallow water at night. A few logs prevent continuous visual contact between individuals. Adult female specimens require access to a terrestrial section that offers a place for oviposition. This section has to conform to the size of the animals, of course, with minimum dimensions being 70 × 50 cm. It should be filled with a substrate of moss of at least 25 cm thick. Schaefer additionally heated the terrestrial section by means of a heating cable. Light The matamata is generally thought of as nocturnal, and observations in the wild seem RADIATA 17 (3), 2008 21
