Kinosternon scorpioides (Linnaeus, 1766) ranges from Mexico to Argentina, where it is often found in murky bodies of water. Despite its wide distribution, little is known of its natural history. We know of no reports about the hatchling and early juvenile stages, which are known only from uncaptioned drawings in Gunther (1902). A presumed hatchling is recorded is recorded from Cayenne (Pritchard and Trebbau 1984). The following notes regard behavior in captivity of a single individual of K. s. cruentatum, and are published because our many attempts to obtain further specimens failed. At the beginning of the 1983 dry season, two K. scorpoides were hand-collected while they were motionless in a bed of mud and leaf trash in Central Costa Rica (San Pedro de Pavas, San José Province). Adults of the species have been reported at this pool (Acuña et al, 1983). At capture, the specimens measured: length of plastron 3.8 and 4.9 cm; carapace 5.0 and 5.2 cm , width of plastron 3.3 and 4.7 cm: carapace 4.8 and 4.8 cm. Their plastral hinges were not functional. One individual died within 20 hours; the other survived approximately 3 months in an opaque aquarium (6 x 7 x 16 cm, with 336 cm3 of water and a small stone as dry section). The observations reported here are based on the longest-surviving turtle, Both specimens are deposited in the Museum of Zoology of the University of Costa Rica (MZ:X-0012). The turtle approached an object put in the aquarium to ca. 1 cm. with head turned laterally, viewing it with only one eye ("visual examination"). Adult insects and Culicid mosquito larvae that were placed in the water often tried to escape as a result of such approach, generally with success. Biting action was accompanied by strong suction of water. which seemed to help capture small prey (e g. Culicid larvae). A similar mechanism has been described in taxonomically distant species, e.g. Chelus timbriatus. If the prey was a fast swimmer (e.g. a hemipteran). the turtle normally abandoned the chase after one or two unsuccessful biting attempts. Its general foraging and feeding behaviors were similar to those of temperate Kinosternids. We believe that the visual sense of this turtle was of key importance in the location and recognition of food, as suggested by the following observations. 1. When 34 Culicid larvae were introduced into the aquarium and the aquarium was placed into a light-tight bag for 46 hours, none of the larvae were eaten. However, as soon as the aquarium was exposed to daylight, the turtle started to consume the larvae The experiment also suggests that the turtle could not locate the larvae by olfactory or tactile stimuli. 2. The turtle approached inorganic dark objects in the aquarium as described above ("visual examination"). 3. By observing suspended silt flow as suggested by Carr (1952), we saw that it rarely sniffed food. When eating prey that was difficult to swallow, such as large earthworms, the turtle showed rhythmic inflations of the neck, which apparently aided ingestion. Finally, the neck was fully extended and bent upwards until the food was totally swallowed. Undesired food parts were expelled orally with a spurt of water.
