SUMMARY
Amazon River Turtle
Description: Males are smaller than females. Amazon River Turtle -We measured 747 males and 88 females in rio Guaporé, Rondónia, Brazil; carapace length in males ranged from 9.8 to 36.9 cm (mean = 26.4) and in females, 12.4 to 46.5 cm (mean = 35.0); males weighed 0.15-4.30 kg (mean = 2.26) and females, 0.30-11.20 kg (mean = 5.77). Females are mature at 31.3 cm in Brazil. These data are similar to those in Colombia, where males reach 27.3 cm and females, 43.4.
The largest Venezuelan specimen measured 46.5 cm in carapace length.
Adult females in Perú Amazon sandova lake on the Samiria River measured 38.6-51.8 cm (mean = 44.5, n = 33) in curved carapace length and weighed 5.25-11.00 kg (mean = 8.17).Another sample of 54 nesting females on the Pacaya river gave very similar results, with curved carapace lengths of 38.0-50.5 cm (mean = 44.7).After nesting, 17 weighed 6.05-12.50 kg (mean = 8.73).
The largest and heaviest one of this sample had a straight- line carapace length of 47.7 cm and a plastral length of 43.1 cm, evidently the largest specimen on record in this amzon wildlife (Sandoval Lake).
Amazon River Turtle
The Amazon River Turtle carapace of hatchlings is dark gray – amazon river turtle brown, or olive green with a yellow-orange border, that of adult males is often black while that of females tends to be gray or light brown. The
anterior lobe of the plastrón is broader than the posterior lobe.
The distinct anal notch is larger in males than in females.
The plastrón is yellow in juveniles but mottled or brown or black in adults.
The head has a notched upper jaw and elongated snout.The upper surface of the jaw has two ridges.presumably functional for cutting and crushing plant material.
An elongated interparietal scale incompletely separates the parietals.
An interobital groove is absent.
Usually one, sometimes two, chin barbéis are present.The head of juveniles and males is dark green or brown with bright yellow orange spots.
The spotting pattern varíes between populations and individuáis, but generally there are postorbital, suborbital,
interorbital, nasal, and parietal spots, as well as elongated spots above the tympanum and along the lower jaw. The
heads of adult females are uniform rust brown.The limbs and tail are gray, black, or light brown.
Males have a longer, thicker tail and retain the juvenile head coloration, but it is less brilliant. The pattern may be lost entirely in some males (Sandoval Lake).
Distribution Amazonia Wildlife (Sandoval Lake) to Amazon River Turtle .
The Yellow-spotted Amazon River turtle has a wide distribution in tropical lowlands of northern South America in
the Orinoco and Amazon River basins of Venezuela, eastern Colombia, eastern Ecuador, northeastern Sandoval Lake
Amazon Peru, French Guiana, Guyana, Surinam, the Amazon River Basin in northern Brazil, and northern Bolivia.
Habita in the Amazon Peru (Sandoval Lake )
Podocnemis unifilis thrives in a wide variety of habitats: large rivers, lakes, oxbow Manu park Sandoval Lake , marshes, swamps, and ponds and creeks, while the adults flourish in largor bodies of water.
The Yellow-spotted Amazon River un tic are fond of basking and appear to be quite social, basking in large groups on logs, often on top of each otlier. They bask less frequently on sandbars. Both sexes and individuáis of all sizes can be seen basking.
Groups of juveniles tend to bask together rather than with adults. Sex ratios were found to be skewed 6:1 in favor of males in Guaporé river in Rondónia, Brazil, but 4:1 in favor of females in a tributary ofTrombetas river.
These differences may represent the effect of temperature- controlled sex determination on the primary sex ratio produced in these areas or may be the result ofdifferential predation on nesting females in Amazon river (Sandoval Lake).
ITINERARY
Food Habitsn Amazon Wildlife Nature – Amazon River Turtle .
Examination of stomach contents of 100 P unifilis revealed that individuáis of all sizes contained only plant material, with water hyacinth (Eichhornia crassipes) the most abundant species in Amazon unifilis fed on fruits, including munguba {Bombax munguba), caiembe (Sorocea duckei), and cramuri (Gymnoluma glabrescens).
Juveniles of both species of Podocnemis have been observed in captivity feeding on plant particles floating on the water surface, behavior known as neustophagia. The turtle raises its head slightly above the water and opens its mouth when the lower jaw is parallel to and slighdy below the surface; water and suspended particles are then sucked into the throat as the throat is distended by protraction of the hyoid apparatus.
The mouth is closed and the hyoid retracted, resulting in the water being expelled but the particles retained in the throat by the erection of Trueb’s papillae.
Fresh stomach contents of Podocnetnis unifilis (n = 351) from the rio Guaporé jn Rondónia, Brazil, were found to contain predominantly plant material, representing 89.46% of the volume 0f stomach contents, compared with only 1.15% animal material.
Seeds and fruits were eaten more than any other category, 38.9% by volume. The most frequently eaten plant families by frequency of occurrence in the stomach contents were Convolvulaceae, 73%; Leguminosae, 54%; Euphorbiaceae, 48%; and Poaceae, 36%. Consumption of fish was low (0.95% of the total volume). Most fish consumed were small and whole, and were probably consumed live and not taken as carrion.
Scales, flesh, and vertebrae of large fish were also present, suggesting that the turtles eat carrion. Insects occurred in such low numbers and volume (0.005%) that they may have been taken incidentally along with the plants (Sandoval Lake).
Even though crabs (Pseudothelphusidae)
occurred in 10.8% of the stomachs volumetrically, they represented only 0.05% ofthe food consumed.
Algae (Chlorophyta) were found in only 4 stomachs in July. Seeds and fruits of Leguminosae, fruits of Maripa sp. (Convolvulaceae) and Margaritaria nobilis (Euphorbiaceae), and seeds of Pouteria sp. (Sapotaceae) and Dispyros sp. (Ebenaceae) were present in the stomach contents throughout the year.
Other dicotyledons were eaten, but only in a few months of the year. Although leaves and stems were consumed throughout the year, more were eaten during the falling water level season. Females consumed more seeds and fruits, while males ate more Poaceae stems.
Nesting in the Amazonia Nature :
The egg-laying season varies widely throughout the range. In Venezuela, egg laying takes place from late January through February in the early dry season. In Amazonian Brazil, Colombia, and Perú, egg laying is dependent 011 the receding river level; since the rainy season varies geographically, and since the water levels of some rivers are controlled by snowmelt in the Andes, the nesting season ranges from June through February;June- July in Purus river; September-October in Trombetas river and Tapajós, Guaporé, Amapá, das Mortes river; December-January in Branco river, Negro river, and Juruá river (Sandoval Lake).
In Pacaya river,
Perú, the nesting season is |uly-August, and December-January in the Orinoco in Venezuela. Podocnemis unifilis lays eggs about 2-3 weeks before expansa and again 2 weeks later, because females of unifilis lay 2 clutches of eggs in
Brazil. One or two clutches of hard-shelled elliptical eggs are laid during the extended 2-month nesting season in each area: 16-33 eggs per clutch in Brazil; 14-49 in Perú; 35-40 (mean 27.4, n = 19) were found in the Putumayo river on the Colombian-Peruvian border and 11-17 eggs (mean = 22.4, n = 14) from the Colombian llanos.
Five clutches from rio Guaporé ranged 16-34 eggs (mean = 31.8), eggs weighed 14-35 g (mean = 29.1), and measured 44.9 (34-48) by 31.8 (25-34) mm. Clutches of 14-31 (mean = 23.3, n = 19) eggs, averaging 31 x 46 mm and 26.5 g are laid in the Capanarparo River in Venezuela from late January to the end oí February.
Most females in oxbow lakes and ponds migrate to rivers to lay eggs, sometimes Crossing several hundred meters of land to do so. However, a few females remain in the lakes and ponds and lay eggs on their shores.Inpreparation for laying eggs, the female digs a nest cavity with her hind feet ca. 20 cm deep and, upon laying, covers the clutch, which remains buried under 5-15 cm of sand or soil.
On the Pacaya, the digging, egg-laying, and covering of the nest usually took 34-63 min (range 26-79, n = 44). Diurnal nesting tended to take less time than nocturnal. Incubation is direct, taking 45-70 days, depending on incubation temperature, which depends on soil texture, depth, and sun exposure on beaches on the Guaporé River, Rondónia, Brazil. On the Pacaya, hatching (pipping) occurs normally after 55-70 days of incubation (Sandoval Lake).
The hatchlings leave the egg shells 2-7 days later and ascend to near the surface,
where they remain piled one upon another for a few days to several weeks, depending on weather conditions.
The hatchlings usually emerge from the nest at night, during or after a heavy rain. In most cases this takes place 72-97 (mean = 87) days after oviposition, but the observed range was 66-159 days. Several hundred just-emerged hatchlings examined on the Pacaya had carapace lengths of 3.4-4.4 cm and weighed 9.0-19.5 g. In Brazil, too, emergence was observed to take place usually at night after heavy rains. Hatchlings measuring 3.7-4.2 cm in carapace length and weighing 11.5-15.1 g emerge from the nests soon after hatching, to avoid predation by hawks, crows, mammals, and fly larvae, and inundation by rising water levels. In Perú Amazon (Sandoval Lake ), nests are preyed upon principally by tegu lizard (Tupinambis teguixin), black caracara (Daptrius ater), black vulture (Coragyps atratus), great black hawk (Buteoaallus urubutinga), and yellow-headed caracara (Milvago chimachima).
Ants, tayras (Eira barbara), opossums (Didelphis marsupialis), and jaguars (Panthera onca) are also responsible for some nest predation.
On the Manu river ofsoutheastern Perú,
a species ofmole cricket {Grillotalpa sp.) was found to be the most frequent natural nest predator and has also been reported to prey on eggs in Colombia.
In Colombia and Venezuela, the crested caracara (Careara plancus) and tegu lizard were identified as the principal nest predators.
In Brazil, the black hawk was found to be the most important predator of eggs in recently constructed nests. Fly larvae (Sarcophagidae) were also important nest predators in both the Guaporé and Trombetas rivers.
On the Pacaya, approximately 23% of the nests are destroyed by natural predators; a few additional nests are destroyed accidentally by other females and iguanas (Iguana iguana) while digging their own nests. Untimely flooding of nests by rising river level was the most important natural cause of clutch losses, varying between years from 1% to 50%.Vultures, gulls, cormorants, caracaras, caimans, and numerous fish are responsible for predation of hatchlings making their way to and in the water. Predation of nesting females by jaguars is common in both Perú and Brazil.
The empty shells, perforated through the carapace or cracked open like a nut, are found on beaches or in nearby vegetation in Amazon nature (Sandoval Lake)