Análise comportamental no uso de habitat e predileção de substratos por Chelydra serpentina.

Abstract

The Snapping turtle (Chelydra serpentina), an exotic species that occurs in North America, is one of the most aquatic species among freshwater turtles. They spend most of their lives deep in lakes or buried in mud in shallow water with only their eyes and nostrils exposed. They can measure up to 47 centimeters and weigh more than 34 kg, have large head and eyes arranged dorso laterally on the back. Large and powerful jaws, the lower jaws are straight and the upper jaws hooked with short snout, so due to its aggressiveness it is known as Snapping turtle. They are most active during the warmer months, but were seen active in winter. Most go into hibernation at the end of October: they bury themselves in the mud under logs, burrows, rocks or plant debris. When they hibernate, they do not breathe, they make gas exchange across the membranes of the mouth and throat, which is known as extrapulmonary respiration. To compare substrate preference and habitat use among semi-extensively captive Chelydra specimens to see if they behave similarly or, if they vary from one specimen to another, observing whether there is a preference for a particular substrate in the open environment as well as the interaction between individuals. For the proposed study, we used five specimens kept in the semi extensive vivarium of turtles and lizards that were displaced to the Reptário, a public exhibition area still under maintenance, where pilot tests for animal release are performed.The specimens are transported in the institution's electric cart, in containment boxes and released in an area with availability of water, sand, grass and stone. The animals were free to choose the substrate. The observations occurred in two moments: the first in the vivarium where they were observed in their own boxes with water and vegetation and the second in the Reptário, both in the morning and afternoon, with several variables for being in an open environment. Random pairs were observed in order to see beyond preference, substrate use and interaction between individuals. Observations in the Biotério and the Reptário showed that sunlight is essential, they became extremely active with heat, especially when temperatures ranged from 20oC to 34oC, but always looked for a place to bury and they move around more into the water. Observations in the Reptário prove that they are really fond of water during all the periods.