Cistude
The diet of an individual within a species may change with age, sex, and season, and may differ between populations. In many species, juveniles are generally carnivorous but become more herbivorous as adults. With Barbour's map turtle, the larger female mainly eats mollusks while the male eats mostly arthropods. Blanding's turtle may feed mostly on snails or crayfish depending on the population. The European pond turtle has been recorded being mostly carnivorous much of the year but switching to water lilies during the summer. Some species have developed specialized diets such as the Mekong snail-eating turtle, the hawksbill, which specializes on sponges, and the leatherback, which feeds on jellyfish.