Red-eared Sliders observed engaged in various activities in the Trinity River at River Legacy Park in Arlington, Texas.
Wikipedia describes the Red-eared Slider in this way:
The carapace of this species can reach up to 30 cm in length, although some individuals have been known to reach more than 40 cm, but the average length ranges from 12 to 20 cm. The females of the species are usually a little larger than the males. They can live between 20 and 30 years, although some individuals have lived for more than 40 years. Their life expectancy is shorter when they are kept in captivity. The quality of the habitat where they live can also influence their lifespans and quality of life.
These turtles are poikilotherms, so are unable to regulate their body temperatures independently; they are completely dependent on the temperature of their environments. For this reason, they continually need to sunbathe to warm themselves and maintain their body temperatures. If their body temperature falls below a threshold of 21°C, they are unable to carry out normal functions of digestion and defecation.