Herbert Meier & Ingo Schaefer and the following report is based on the observations made during round about thirty years of keeping matamatas. Added to these are the results of excursions into its natural habitats in the Amazon region. Details are provided on various aspects of its captive care, including feeding behaviour and annual and diel activity patterns. Various types of husbandry conditions are portrayed and explained as to why they were altered over the years. These are discussed in comparison to the situation in the wild. It must be pointed out here that Ingo Schaefer no longer keeps matamatas. His animals are still in the best of health, though, and now live in the Rotterdam Zoo where they are looked after by Henk Zwartepoorte. History In the first handbook for the terrarium, Fischer (1884) noted the following (in transl.) for the matamata: “...it will certainly be imported soon due to its curious appearance and build. It will, as only very young animals can be used for the terrarium, probably be in need of a warm and moist terrarium with a spacious water basin, because it leads an almost exclusively aquatic life. It is believed that it is easily kept alive for a long time on a diet of grass and bread.” By now, our knowledge of this fascinating turtle has increased dramatically. But still, many questions have remained unanswered. Distribution The distribution range of Chelus fimbriata lies in the north of South America and includes the entire drainage of the Amazon and Orinoco Rivers in the widest of senses. Its natural dispersal is limited by the Caribbean in the north and by the Atlantic Ocean in the east, while the mountains of the Andes form a natural barrier to the west. Towards the south, the species does not occur beyond the tributaries of the Amazon River (see, e.g., Vetter 2005, Barrio-Amorós & Narbaiza 2008). It appears to be fairly common at least in some places, although its presence is easily overlooked due to its secretive ways of life. Surveys recorded it from the lower Brazo Casiquiare, the Río Negro, and from the Llanos of Venezuela. The matamata forms an integral part of the menu of many native Indians, who, according to statements made by members of various tribes, such as the Yeral, Yanomami and Kuripaki, at least collect its eggs for consumption. Description Chelus fimbriata is the largest representative of the family Chelidae. German-language literature contains only little in terms of exact information on size, with approximations like “more than 40 cm” or “45 cm or more” being common (e.g., Nietzke 1977, Nöllert 1987, Rogner 1996). In fact, it is safe to suppose that this species can reach lengths of about 60 cm. The longest specimen mentioned by Pritchard & Trebbau (1984) was a female with a dorsal shell of 45.6 cm in length that had been collected at Puerto Ordaz (Bolivar State, Venezuela). In May of 2000, the senior author found the complete shell of a male Chelus fimbriata in the vicinity of the Río Caura Falls in Venezuela that measured 48.5 cm in a straight line. A note on a calculated size of 52.8 cm is found in Sanchez-Villagra et al. (1995), and Kabisch (1997) reported on the find of a shell measuring 64.5 cm in carapace length in Ciudad Bolivar (Venezuela). As has been stated in the introduction, Chelus fimbriata is absolutely unique. Its appearance makes a lasting impression even on the casual observer: the carapace is oval in its outline and dominated by three distinct keels, with the vertebral and costal scutes being raised in a curious, cone-shaped manner. The head is flat and triangular when viewed from 18 RADIATA 17 (3), 2008
The Matamata, Chelus fimbriata above. Like the neck, it is furnished with an assortment of skin flaps and carries scurrilous barbels and tubercles, which altogether lend it prehistoric flair. Neck and head about correspond in their combined length to the length of the carapace. The large, low-set mouth suggests that large prey can be swallowed. The eyes are so small that it takes a good look to find them, which cannot be said for the prominent, snorkel-like nose. The colouration of the dorsal shell varies from light brown in juveniles, through dark brown in adults, and blackish brown in very old specimens. The lower side of the neck is brown to red in colour and sports dark brown to black stripes, while there is a black, arrow-shaped marking on the upper side of the neck. Traits of sexual dimorphism are relatively weakly expressed. Males are usually smaller than females, the plastron is slightly concave, the tail thicker and longer, and the distance from the cloaca to the plastron is a little greater than in female specimens. The vast distribution range suggests the existence of subspecies or at least geographical variation. Pritchard (1979) reported on differences in colouration in Chelus fimbriata from Brazil, Peru and Colombia. Based on examination of 126 Chelus fimbriata, Sanchez-Villagra et al. (1995) distinguished in principal between two varieties: the Amazon and the Orinoco Types. These forms are said to differ as to the shape of the carapace, colouration of the plastron, and colouration of the ventral side of the neck. The animals previously kept by Schaefer would thus conform to the Amazon Type, whereas those in the collection of Meier are all of the Orinoco Type. In adults, the different shapes of the carapace are clearly visible: nearly “rectangular” in the Amazon Type and oval to oviform in the Orinoco Type. Likewise obvious is the difference in the colouration of the plastron: While the ventral shell of Amazon-type specimens is brown to dark brown, that of Orinoco-type animals appears yellowish or ochre to light brown. This difference is even more clearly expressed in juveniles: The Amazon Type sports a largely dark to black ventral shell with bright red spots, whereas the Orinoco Type is unmistakable for its predominantly light red ground colour and a few dark spots. The red colouration of, respectively the striped pattern on, the lower side of the neck tends more towards brown in the Amazon Type. The origin of the animals previously in the care of Schaefer is unknown, but could be, as he himself hypothesized in 1986, Peru. According to Schmidt (1966) and Sanchez- Villagra et al. (1995), as well as based on a Chelus fimbriata that was caught and photographed during the course of an expedition to the Río Pastaza, Ecuador, in 1999 and which corresponded in its overall appearance to the Amazon Type, this presumption is entirely reasonable (Meier & Schaefer 2003a). During the course of two journeys to Venezuela, we were able to examine thirty-two live, mainly juvenile Chelus fimbriata from the lower Río Casiquiare and the shell of an adult male from Río Caura, record measurements, and take photographs. All these specimens agreed with the Orinoco Type (comp. Meier & Schaefer 2003a). Further records of Chelus fimbriata from the Casiquiare River, as well as specimens that appeared in the pet trade over the last years and were said to be farmed animals from Peru, fit the criteria given above. It would certainly be interesting to compare matamatas from distant localities. Terrarium Keeping Chelus fimbriata in a captive setting is actually rather easy if only its biological requirements can be met. Notwithstanding this, only a very few of the animals that were imported in large numbers into Europe during the 1970’ and 80’ have survived until now. RADIATA 17 (3), 2008 19
