Not in the traditional sense, but they do have bony plates that are used to cut through sponge and seagrass which are constantly growing.
Well, turtles grow at different rates, just like humans do. Some feed more than others, some exercise more, some are just genetically born to be big or small. This genetic variability ensures that no two turtles are alike, and keeps the population healthy and diverse through evolution.
For instance, if all turtles were genetically identical and a fatal disease was to affect the population, they would all die. However, if some of them had different genetic composition they might resist the disease and survive.
The largest Leatherback weighed in at over 800 kg and reached 2.5 m in length. Most adult green turtles weight 120-180 km and are around one meter in length (but have been known to reach over 200 kg), while most adult Hawksbills weigh 50-100 kg and are roughly 70 cm long.
No, in fact, scales (or more correctly ‘scutes’) counts are a way by which one can tell the difference among species. If the turtle has no scutes, but rather a hard rubbery shell with seven longitudinal ridges, it is a Leatherback.
If the turtle has four pairs of main lateral scutes (the large ones between the main backbone line and the small ones round the edges) it is a Hawksbill or a Green turtle, depending on the number of scales in front of and above the eyes (two pairs: Hawksbill; one pair: Green).
If the turtle has five pairs of main lateral scutes, it is a Loggerhead. More than this, it is an Olive Ridley. These are the five species found in the Gulf region.