Testudo marginata Schoepff, 1792

Taxonomy and Native Status

The marginated tortoise (Testudo marginata Schoepff, 1792) is the largest tortoise species native to Europe.

Adult Size and Weight

Adults can reach a maximum weight of 5 kg (11 lb) and a maximum length of 35 cm (14 in).

General Shell Shape

This species has an oblong shell that is notably thick around the midsection of the body. The posterior end of the shell forms a saw-like structure that flares outward like a bell.

Adult Carapace Coloration

The carapace (upper shell) of adult specimens is almost entirely black with yellow markings.

Plastron Markings

The plastron (ventral shell) is lighter in color and marked with paired triangular spots whose points face toward the tortoise's rear.

Limb Scale Characteristics

The front surfaces of the limbs are covered in large scales.

Female Plastron Flap Trait

In old females, the rear underside flaps of the plastron are somewhat movable.

Tail and Associated Carapace Trait

The tail is distinguished by a lengthwise marking, and the carapace extending over the tail is undivided.

Male Sexual Dimorphism

Males have longer tails that are thicker at the base than those of females, and their undersides have a more prominent indentation. Males are also often larger than females.

Egg Laying Timing

Females lay hard-shelled, spherical eggs in soil during May and June.

Core Natural Distribution

The natural distribution of the marginated tortoise covers southern Greece, spanning from the Peloponnesus to Mount Olympus.

Isolated Distribution Ranges

It also occurs in isolated areas of the Balkans, Italy, and northeastern Sardinia.

Elevation Range and Habitat

Compared to Hermann's tortoise, the marginated tortoise inhabits more mountainous regions, and can be found at elevations up to 1,600 m (5,200 ft).

Carapace Color Thermoregulatory Function

The black color of the carapace helps the species survive in this habitat by letting it absorb large amounts of heat quickly to maintain its body temperature.

Daily Activity Pattern

Early in the morning, marginated tortoises bask in sunlight to raise their body temperature, then go in search of food. After feeding, they return to their shelters to avoid the midday heat, and become active again in the late afternoon.

Reproductive Onset Timing

Reproductive activity begins immediately after the tortoises wake from brumation, when males develop a mating instinct.

Male Pre-Copulation Behavior

Males actively follow females, circle them, bite their limbs, ram them, and attempt to mount them.

Copulation Male Display and Vocalization

During copulation, the male opens his mouth to display his red tongue and produces loud cries. These copulation cries have a sobbing quality with long, deep tones, which differs from the much higher, peeping calls made by Hermann's tortoise (T. hermanni) during mating.

Female Copulation Behavior

During mating, the female remains still, holds her head to the side, and looks up at the male's open mouth; the red tongue is thought to act as a visual signal. The female moves her head from side to side in the same rhythm as the male's cries.

Post-Mating Female Nest Search

After mating, the female searches for a suitable location to lay her eggs.

Nest Digging Process

Once she finds an appropriate spot, she holds still, braces her front legs firmly against the ground, and digs a hole with her hind legs, alternating between the left and right. She starts by lightly scratching the ground, and eventually moves large piles of soil that she deposits beside the hole.

Nest Depth and Soil Softening Adaptation

The depth of the hole matches the length of her hind legs. If the ground is too hard to dig, she softens it by releasing water from her anal gland.

Egg Laying Process

Once the hole is complete, she begins laying eggs. Each egg is gently rolled into the hole.

Nest Refilling Process

After the final egg is laid, she immediately starts refilling the hole with her hind legs, and finishes by stamping the opening closed with her feet to return the ground to its natural hardness.

Clutch Frequency and Size

Larger females can lay eggs up to three times per summer, with around 15 eggs per clutch.

Natural Incubation Period

Under natural conditions, the average incubation period for marginated tortoise eggs is around 100 days, which is relatively short compared to many other tortoise species.

Tropical Tortoise Incubation Comparison

Many tropical tortoise species have incubation periods as long as 200 days. This shorter incubation period is an adaptation to the subtropical Mediterranean climate, where summers are not extended.

Artificial Incubation Parameters

When incubated artificially, the incubation period is noticeably shorter: at a constant temperature of 31.5 °C (88.7 °F), eggs will begin hatching after 60 days.

Reptile Egg Internal Structure

Unlike bird eggs, the yolk and albumen of reptile eggs are not separated by a membrane. After a few days, heavy yolk components sink to the bottom of the egg, with the embryonal disk floating on top, surrounded by albumen.

Egg Handling Constraint

Because of this structure, tortoise eggs cannot be turned after the yolk settles, as this will damage or kill the developing embryo.

Egg Development Visual Assessment

Healthy development of the eggs can be seen with the naked eye. Freshly laid eggs are gray-white in color.

Egg Color Change During Development

Shortly after laying, a bright white spot forms on the top point of the egg, which gradually grows until the entire egg is bright white.

Hatching Initial Process

When the embryo is fully developed inside the egg, the hatchling breaks the shell from the inside using its egg tooth, creates a small opening, and fills its lungs with air for the first time. After this, it pulls back into the egg and continues working on the shell with its beak until the shell opens completely.

Post-Hatch Underground Period

In natural conditions, hatchlings remain underground for their first two weeks, where they are protected from predators and can continue growing nourished by their yolk sac.

Juvenile Habitat Use

Young marginated tortoises live cautious, secretive lives, normally staying in shaded areas. They avoid full direct sunlight because it puts them at high risk of overheating.

Juvenile Growth Rate

Marginated tortoises grow very quickly when young. In an ideal habitat or with good captive care, they can gain between 100 and 500 g (3.5–17.6 oz) per year.

Adult Growth Pattern

This rapid growth continues through their youth, and after reaching 20 years of age, additional growth is minimal.

Maximum Lifespan Estimate

Scientists' best estimates place their maximum lifespan between 100 and 140 years.