Curiously juvenile Mata Matas do seem to enjoy basking, but it is very rare among adults. The only time a land area is required is during breeding, as the female will use this area for egg laying. It should be noted that breeding in captivity is encouraged since they are becoming endangered due to habitat loss in the wild. The Mata Mata Turtle can weight up to 27 pounds, and making him one of the largest freshwater turtles. Their shells can measure 18 inches in length at maturity.
Females are generally larger than males.
When the Mata Mata is first born it has a salmon coloring to its plastron and the carapace and neck are dark brown. However, when he gets older, his plastron turns to yellows and browns. The carapace of the mature Mata Mata is contorted and coarse to the touch. One can gauge the age of these tortoises by examining the growth lines present on each scute. The scutes themselves are conical, and the growth rings are easy to see.