The way of life in the great outdoors
For almost 50 years I have dealt extensively with field herpetology and visit many turtle habitats throughout the Mediterranean several times a year. At first I only observed the animals there and then intensively researched their way of life and behavior.
Depending on the temperature conditions in the different biotopes, the first turtles regularly dig out of their hiding places as early as February to warm up in the spring sun.
By March at the latest, all animals are active again and, depending on the weather, go about their usual life every day.
The only exception to this are the turtle populations that live in higher-lying, cooler biotopes inland.
The turtles living there become active a little later in the year, depending on the temperature, but at the same time the plant growth and the flowering period are shifted further into the summer months.
The daily active phase begins after the first rays of the sun have warmed the floor. The turtles crawl out of their hiding places and take a long sunbath. After reaching metabolic temperature, the turtles are very active. They go to their pastures or explore the area. With the onset of the midday heat, the animals crawl into the thicket and finally become active again in the afternoon.
While the sun is in the sky, the turtles hide again in their hiding places to spend the night buried there.
European tortoises generally avoid open terrain. However, from the point of view of the turtles, larger stones, tufts of grass and small bushes are tree-high. For young turtles, open terrain is extremely uncomfortable because of the predators threatening from above.
Within the habitats, each individual adult animal claims a relatively small roaming area in which its shelter is located. European tortoises have no territory and therefore no territorial behavior, that is, they do not defend their area of action, but live in an open association within the habitats that overlap strongly Grazing areas.
The turtles prefer to burrow under dense, often thorny bushes, larger grass groves, old wood or large stones. Existing small caves or holes in the ground dug by other animals are also gladly accepted as shelter. If nothing changes in the habitat, these hiding spots are used for many years for rest periods and also for wintering.
The shelter is usually inhabited alone by adult European tortoises. In larger caves or wider hiding spots, several animals can sit close together, although there are comparable possibilities in the area.
The individual roaming areas, usually only a few square meters in size, overlap considerably. The action spaces of the males are about twice as large as those of the females. Male animals are also active earlier and longer than their female counterparts.
When two males meet each other in spring, comment fights can be observed on a regular basis. These fights are very similar to the mating ritual and are regularly decided by the larger and therefore stronger animal. These ritualized acts have nothing to do with territorial defense.
Often the order of precedence is clarified after a short smell and the "weaker" one hurries out of the way.
Shortly after the hibernation, the males crawling out of the frozen hibernation in front of the females are already on the move in the larger area of their home area in search of female conspecifics. If they meet a female, they immediately begin with their advertising ritual, which is somewhat different depending on the species.
In addition to laying eggs, the females leave their range, if necessary, only to search for food.
Tortoises are by nature grazers and, depending on the conditions in the individual biotopes, they can walk across larger areas outside their actual range in search of food.
Two females who meet each other ignore each other or at most briefly smell each other and soon go their separate ways again.
In spring it still rains extensively in the entire Mediterranean area, so that the turtles are not only regularly bathed by this often torrential rain, but can also bring their water balance into balance after the winter rest by drinking from the accumulated water.
It is well known that turtles also absorb water through the cesspool and skin.
Favored by the rains, green grasses and herbs grow as early as February. At the beginning of April, the turtle biotopes are the purest sea of flowers. Even barren, barren soils are covered with colorful carpets of flowers. The intoxicating scent of flowers and spicy wild herbs is in the air. In spring, the turtles mainly eat flowers and juicy, fresh, vitamin-rich greens.
In the wild, spring shortly after winter rest and autumn is the main mating season. During these times the turtles are very active.
A few weeks after copulation in spring, the females begin laying eggs for the first time. Depending on the species, the second or third clutch takes place a few weeks later.
European tortoises are very localized. Their ancestral home area is in more or less tree-covered and bushy terrain, which does not always have the necessary full solar radiation and thus a relatively high soil temperature and also not the required relatively constant high soil moisture for the shredding of eggs. For this reason, the pregnant females have to leave their closed range to lay their eggs and go to open, sun-drenched and, above all, more humid areas with very low vegetation. As a rule, these are sinks close to bodies of water, areas below mountain slopes or in sinks with a relatively high water table.
To protect the hatching young from predators, the egg pit is not placed in an open area, but always near a small, open bush.
After laying eggs, the females go back to their actual roaming area, which they can easily find again thanks to their pronounced sense of smell and orientation. The females from all over the area keep looking for the same places to lay their eggs.
Each of us who keep female tortoises has certainly already seen this urge to migrate in our animals. The turtles wander restlessly up and down and try to break out of the enclosure
From the end of May, when the rainfall decreases with the increasing heat, the bloom comes to an end quickly. Most plants don't stand a chance in the scorching summer heat. The grasses and herbs dry up into hay and perennial plants fall into a kind of summer dormancy in order to survive.
During the summer months the turtles have a completely different food available. Apart from individual thick-leaf plants, such as various types of stonecrop and the evergreen bushes or the very popular ones, which occur in large numbers in some places Stinging winds, it is only arid, dry forage. The animals get the vitamins they need in the summer months and the equally vital unsaturated fatty acids by eating seeds, wild fruits and berries of all kinds. These fruits and berries in the habitat are by no means the same as the sweet and watery fruits that we have available and compare berries.
On grazed macchia areas, the plant species quickly become impoverished, which is why the turtles no longer have access to the natural variety of plants. Especially when it comes to nutrition, only the really original primary habitat and not any area that has already been modified and cultivated by humans can be used as a "model of nature".
In spring and again in autumn the turtles need a lot of energy. For this reason, they initially eat almost exclusively freshly sprouted shoots and thus absorb rich protein compounds. The saturated and unsaturated fatty acids have a positive effect on many metabolic processes and strengthen the immune system. In contrast to cultivated plants, wild plants have a higher calcium, mineral, vitamin and crude fiber content with a relatively reduced water content. Most wild plants also contain many health-promoting substances, such as essential oils, bitter substances, flavonoids, tannins, saponins and mucilage and are therefore still used in herbal medicine today.
The essential oils and bitter substances in particular have a positive effect on digestion and help to keep the gastrointestinal tract healthy in the long term. Other ingredients bind poisons, have an antiseptic and blood-purifying effect. All these effects known from folk medicine have only been proven for us humans and mammals, but it can be assumed that these ingredients, like the minerals and vitamins, are equally effective in reptiles.
The spring
A special predilection for certain plants cannot be observed in the spring. The animals graze practically everything that germinates. Also seedlings and fresh shoots of plants, bushes and trees that they usually spurn in the fully grown stage, such as most species of sage ( Salvia sp. ) Or the leaves of the rock roses ( Cistus sp. ). Because of this diversity, the turtles have a varied and balanced diet. The various plants contain all the important basic nutrients, which is why deficiency symptoms in the primeval maquis are excluded.
In the following growing season, European tortoises show a preference for all dandelion-like rosette plants that contain milky sap. Usually these are daisy flowers (Asteraceae). Many spicy-tasting cruciferous vegetables (Brassicaceae), legumes (Leguminosae), most species of clover (Anthyllis, Dorycnium, Lotus, Medicago, Trifolium) with the exception of the oxalic acid-containing bitter clover species (Oxalis) and many other butterflies and labiates are also eaten with preference Lamiaceae) and carnation family (Caryophyllaceae).
The summer
In early summer, the turtles prefer to eat flower buds and flowers, especially those of red and yellow flowering plants and in the further course all kinds of wild fruits, the still green seed pods and pods and finally the various seeds themselves. However, wild fruits are in no way associated with the watery ones grown for human consumption to compare sweet, sugary fruits. They are predominantly dry, taste bland and contain little fructose. In midsummer the animals eat almost exclusively only dry plant components and leaves from various trees and bushes. The turtles also gnaw very persistently on bark and roots, some of which are downright dug up.
In this barren time, the turtles perform the most daring climbing skills to get to leaves, wild fruits and seed pods. In this time, when there is a shortage of forage crops, the energy-rich seeds, due to their high proportion of vegetable oils with valuable saturated and unsaturated fatty acids and protein compounds, are important for a healthy diet and consequently also for successful reproduction.
Until well into the hot summer, forage plants are still green and bloom extremely profusely. Cardiac plants such as the scabiosa (Scabiosa), the chicory (Cichorium intybus), the little meadow button (Sanguisorba minor) are most represented here. and various convolvulaceae and thistle species.
The autumn
In autumn, when the macchia awakens to its "second spring" after the first autumn rains, the circle closes again with the germinating young plants, which are now also available to the hatchlings as the first energy and nutrient-rich source of food.
General
Rough, dry parts of plants, like the older leaves of most trees and bushes, are only eaten by the turtles when the fresh green plants have dried up in midsummer and the trees and bushes no longer have any young shoots.
Resinous plants such as the Aleppo pine (Pinus halepensis), the star pine (Pinus pinaster), the tamarisk (Tamarix), the wild juniper (Juniperus oxycedrus) and shrubs that are very common in some habitats are not or only really eaten in an extreme emergency of the Phoenician juniper (Juniperus phoenicea). However, I have often found the ripe juniper berry cones, 8 to 14 millimeters in size, in turtle droppings in late summer. Especially in the summer months, excrement soaked in water gives a good insight into the nutrition of the turtles. Many hard-leaved leaves such as those of the strawberry tree (Arbutus unedo) and hard, hard-to-digest fruits such as the 10 to 30 millimeter large, bright orange-brown fruits of the dwarf palm (Chamaerops humilis) can be found next to snail shells and small limestone of various sizes.
Obviously none of the species of milkweed family (Euphorbia) and herbs containing various essential oils such as rosemary (Rosmarinum officinalis), lavender (Lavandula sp.), Marjoram (Origanum sp.) Or the karst mountain mint (Satureja montana) are not eaten at all.
Toxic plants
European tortoises also value plants with substances that are toxic to humans and mammals. Above all, various buttercups (Ranunculaceae) and predatory plants such as the various types of adder's head (Echium) that occur in abundance in the habitats and are part of the turtle's staple diet. But also highly poisonous species such as the sea onion (Urginea maritima), which was previously used as a rat poison, arum plants such as the Italian arum (Arum italicum), the crook (Arisarum vulgare) or the common serpent (Dracunculus vulgaris) and the common wreath that covers entire bushes (Tamus communis), are preferred to eat. The butterfly flowers of the many types of gorse, such as the gorse (Ulex euro-paeus), the broom (Cytisus scoparius) or the hairy thorn (Calicotome villosa) and the prickly thorn (Calicotome spinosa) are just as popular. Gorse, especially in its leaves and seeds, contains alkaloids that are highly toxic to mammals. In Sicily I have often seen turtles feasting on fallen poisonous oleander flowers (Nerium oleander).
The sedum species, which are often very abundant and which are also classified as poisonous due to their oxalic acid content, which disrupts calcium metabolism, are also preferred.
The difference between medicinal substance and poison, however, is only a matter of dosage. Even the most important doctor and natural philosopher Paracelsus had the following insight: "All things are poison and nothing is without poison, only the dose makes that a thing is not poison."
The need for lime
The plants grown on calcareous soils contain enough calcium to adequately supply adult turtles. The increased calcium requirement that females need to shell their eggs and young animals for building bones and the bone shell is something that the turtles get in very different ways. Even the hatchlings are still eating their own egg shells in the egg pits and are later specifically looking for small white limestone stones. Wild turtles only eat the stones to absorb minerals and trace elements and not to drive out intestinal parasites or to aid digestion like birds do.
I have often seen young and old turtles eating from empty houses of the bush, tower and snail snails lying around. The bones of dead animals lying around in the maquis are also used by the turtles as a source of lime. The turtles gnaw at the bones with infinite persistence as we otherwise only know it from dogs. Sepia shells are sometimes found in large numbers on the beaches in spring and are carried far into the country by the wind and also by the seagulls. Eggshells, which lie in abundance in the abandoned ground nests of pheasant, partridge, stone fowl and quail, are also used as a source of lime.
Extra food
The droppings of herbivores such as rabbits, deer, sheep and goats are also very popular with turtles. I have also seen turtles feeding on wild boar droppings. Eating feces is innate in turtles. Hatchlings eat the excrement of older conspecifics in order to vaccinate their intestinal flora as quickly as possible with specialized bacteria and protozoa. Without this intestinal flora, fermentation of the feed and thus the removal of nutrients from the feed pulp would only be incompletely possible. Herbivore faeces regularly contain concentrated undigested nutrients and a whole range of excess vitamins and minerals that the turtles use in addition.
Animal food in the form of snails or small insects is more likely to be eaten by turtles in the wild. However, according to reports, turtles do not stop at carrion. In many conversations with locals myself, I have not yet met anyone who has made similar observations. Although I occasionally found dead animal carcasses in habitats near active turtles, I have never seen a turtle feeding on them myself. I think these are negligible individual observations outside of primary habitats.
You can find detailed information about nutrition and a selection of well over 300 forage plants in my book Forage Plants
