Greek tortoises (Testudo graeca) are also called "Mediterranean spur-thighed" tortoises. The photos below shows you why. :O) Look at those big spurs (conical tubercles) on that male golden Greek's legs.
Greek tortoises can have one, two, or even three spurs on each back leg. Both males and females have leg spurs, and they are already present in baby tortoises. One of my adult golden Greeks has large double spurs while the others have single spurs.
In many cases, the presence or absence of these leg spurs makes it easy to distinguish between Greek (Testudo graeca) and Hermann's (Testudo hermanni) tortoises. Most Greeks have leg spurs, while most Hermann's do not. Instead, Hermann's tortoises have a terminal nail spur, a horn shaped scale, at the tip of their tails. Greek tortoises have blunt tails with no tail spurs.
Caution! The absence or presence of thigh spurs can not be relied upon as the only means of determining the species. Some Hermann's tortoises have thigh spurs, and some Greeks do not have spurs.
In most adult golden Greek tortoises thigh spurs are easy to see, but in some older tortoises, the spurs can be worn down flat to the skin level. It may then appear like there are no spurs present, especially if the diameter of the spurs is small.
Double spurs on the back leg of an adult male golden Greek.
Large, worn down spur on an adult female golden Greek.
In golden Greek babies, tiny leg spurs are already present at hatching.
Thigh spurs on a one-month-old golden Greek / Mesopotamian tortoise baby.
Another golden hatchling. This one is only 3 days old. Look at those baby thigh spurs.
In addition to Greeks, some other tortoise species also have leg spurs, most notably, the sulcata aka "African spurred tortoise" (Centrochelys sulcata). Greek tortoises (Testudo graeca), commonly known as "Mediterranean spur-thighed tortoises" in Europe, stay small, but Sulcatas can grow huge (175+ lb). Sometimes people get confused with these two very different species due to both of their common names having the word "spur" in it.
Burmese star tortoises (Geochelone platynota) have multiple small spurs on their thighs and mature males may have a sharp spur on the tip of their tails. These tail spurs start to grow when males approach maturity, and they can also drop off or wear down over time.
My male below grew his tail spur into a "hook" later on (not pictured) and then lost it. One day I just noticed that the spur wasn't there anymore. He has not grown another one to replace it.
A mature Burmese star tortoise male with a terminal tail spur (nail). This tail spur can be much longer than pictured in some males and even be shaped like a hook.
Multiple thigh spurs on a Burmese star tortoise. No tail spur on this one.