Nesting activity of the neotropical turtle Phrynops hilarii Duméril & Bibron, 1835 was studied from Feb/94 through Jan/95, with weekly visits at the Lami Biological Reserve (30º15'S, 51º05'W), Porto Alegre, Rio Grande do Sul, Brazil. Nesting behavior was observed 17 times on three different nest sites. Phrynops hilarii laid in average 11 eggs per clutch (10-14; sd±1; n=17), nests' depth ranged from 100 to 150 mm (x=121.53 mm.sd±12.31; n=17). The species presents stereotiped behaviour common to other Testudines. Temperature inside the nest, just after nesting, ranged between 20-31ºC (x=26.29ºC; sd±2.89; n=17); nest predation during this period was 82.35% (14 of 17 nests). From Aug/29 through Oct/03/95, 220 egg shells was collected next to 21 nests destructed by predators in the same sites. At the Reserve, the main nest predator is the nocturnal mammal Procyon cancrivorus Cuvier, 1798.

Liolaemus occipitalis (Boulenger, 1885) is an abundant lizard lbundalong lhe coastal dunes of Rio Grande do Sul, Brazil. Fourteen individuais were manually captured in the dunes of Quintão beach (Palmares do Sul, Rio Grande do Sul) and studied in captivity from 23/VII/92 to 30/VII/93. They were kept in a terrarium with sand substrate and vegetation collected in their habitat. Snout-vent length (SVL) and wcighted were measured weekly. They received Tenebrio molitor (Linnaeus, 1758) worms as food; water was abundant. Combats between males for food and territory, and other behavioral displays were observed, like copulation and nesting behaviors. Growth curves for each lizard were analyzed.

The activity rhythm of the lizard Liolaemus occipitalis Boulenger, 1885 was studied during the summer of 93 at the sand dunes of the Quintão beach, from 06:00-18:00h. During sunny days this lizard exhibited two peaks of activity (1000-1200h and 1400-1600h), and in the cloudy days it exhibited one peak of activity (1200-1400h). The number of burrows was observed and the different soil temperatures was compared with the rhythm of activity exhibited by the lizards. Rhythm of activity is determined mainly by soil surface temperatures.