Testudo hermanni
Hermann's tortoise
Scientific name: Testudo hermanni
Common names: Hermann's tortoise
Subspecies: Two currently recognised subspecies: T.h. hermanni (most threatened) and T.h. boetgerri (includes T.h. hercegovinensis) (1)
Identification: Hermann's tortoise is a small to medium sized tortoise with a carapace length that rarely exceeds 20cm but can be as little as 12cm (2,3). T. hermanni differs from T. graeca in that it lacks spurs on its thighs and has a large scale on the tip of the tail. Colour varies from yellow-orange to grey, with bold black markings (2).
Range: T. hermanni has a patchy distribution along the coast of France, Italy, Spain, Manorca, Mellorca, Corsica, Sardinia, and Sicily. It's range covers most of the Balkan peninsula, including inland areas; Albania, Bosnia and Herzegovina, Croatia, Serbia and Montenegro, Romania and Bulgaria (4).
Natural history: Habitat: As reptiles, tortoises need to regulate their body temperature through behaviour. Hermann's tortoises shuttle between shady and sunny patches to achieve this. They therefore occupy habitat that contains both densely vegetated areas where they can rest and hide from predators, and open areas where they can feed and bask (5,6,7) (figure 3). Where it still exists, their preferred habitat is Mediterranean oak forest, though they are commonly found in maquis or garigue habitat on hillsides and farmland, or in dune scrubs or maritime grassland (3). Some small, isolated populations also exist in urban parks, for example in Rome (8). |
Home-range:
Hermann's tortoises are not territorial and stay within stable home-ranges. They are therefore highly familiar with the local microenvironments, which improves their ability to successfully thermoregulate (9). Longepierre et al (6) found that the home-range of Hermann's tortoises depends on the complexity of the habitat: tortoises in a complex maquis habitat had home-ranges as large as four hectares, whereas those of tortoises in a simpler coastal heathland habitat were less than a hectare.
Density:
Population densities of the eastern subspecies (T. h. boetgerri) vary widely, from less than 3 to almost 80 per hectare (10). The western subspecies (T. h. hermanni) is found in much lower densities (3,11). Hailey and Willemsen (10) found a skew in the sex ratio that favoured males in populations at high densities. This may be as a consequence of female mortality from persistent harassment from males or injuries from mating behaviour (10). Unlike other Testudo species, for whom courtship only consists of shell-butting, male Hermann's tortoises also repeatedly stab at the females cloaccal region with the horny tip of the tail. This can lead to infection and may be a source of mortality, particularly in densely populated areas (3).
Reproduction and hibernation:
Generally speaking, Hermann's tortoises start mating at the end of July and continue through the summer. Sperm is stored by the female for use in the next season, as eggs are laid between May and July in France, and slightly earlier in Greece. The eggs hatch in early September. This species hibernates from November to March, with occasional and brief emergences during winter (3).
Diet:
As with all Mediterranean tortoises, Hermann's tortoise is strictly vegetarian, feeding on a range of herbaceous and succulent plants. The diet of the population in Montenegro studied by Meek and Innskeep (5) was found to consist mostly of leguminous plants, which are a high quality source of protein.
Hermann's tortoises are not territorial and stay within stable home-ranges. They are therefore highly familiar with the local microenvironments, which improves their ability to successfully thermoregulate (9). Longepierre et al (6) found that the home-range of Hermann's tortoises depends on the complexity of the habitat: tortoises in a complex maquis habitat had home-ranges as large as four hectares, whereas those of tortoises in a simpler coastal heathland habitat were less than a hectare.
Density:
Population densities of the eastern subspecies (T. h. boetgerri) vary widely, from less than 3 to almost 80 per hectare (10). The western subspecies (T. h. hermanni) is found in much lower densities (3,11). Hailey and Willemsen (10) found a skew in the sex ratio that favoured males in populations at high densities. This may be as a consequence of female mortality from persistent harassment from males or injuries from mating behaviour (10). Unlike other Testudo species, for whom courtship only consists of shell-butting, male Hermann's tortoises also repeatedly stab at the females cloaccal region with the horny tip of the tail. This can lead to infection and may be a source of mortality, particularly in densely populated areas (3).
Reproduction and hibernation:
Generally speaking, Hermann's tortoises start mating at the end of July and continue through the summer. Sperm is stored by the female for use in the next season, as eggs are laid between May and July in France, and slightly earlier in Greece. The eggs hatch in early September. This species hibernates from November to March, with occasional and brief emergences during winter (3).
Diet:
As with all Mediterranean tortoises, Hermann's tortoise is strictly vegetarian, feeding on a range of herbaceous and succulent plants. The diet of the population in Montenegro studied by Meek and Innskeep (5) was found to consist mostly of leguminous plants, which are a high quality source of protein.
Threat Status: Currently classified as Near Threatened by the International Union for Conservation of Nature (IUCN). This means that it likely to be classified as threatened in the near future. Any taxon listed by the IUCN in a threatened category is considered to be facing high risk of extinction in the wild. See here for full classification criteria used by the IUCN.
Threats: Habitat loss through urbanisation, forest fires and tourism are of major concern for this species (3,7,12) with pleas for it's protection going as far back as 1925 (13). Changes in agricultural practice have also heavily impacted the species. The loss of clearings that were traditionally maintained by people has forced large numbers to nest together in the few remaining sites. This unnaturally high density of nests attracts mammalian predators which have been found to destroy 90% of nests each year (3). |
Collection for the pet trade exacerbated declines in the middle of the 20th century, when some years saw tens of thousands being removed from the wild (figure 3). Though trade in wild-caught Hermann's tortoises is now illegal, tortoises are still taken by locals and tourists to be kept as pets: in France it is thought that there are more native tortoises in captivity than in the wild (3). Combined with habitat loss collection can lead to local declines.
It is predicted that there will be dramatic changes to temperature and precipitation levels in the Mediterranean region (14). This will have as yet unknown effects on tortoise populations. A study by Fernandez-Chacon in 2011 (15) attempts to predict what effect climate change may have on Hermann's tortoises. In this study the authors used over 20 years of data to look at patterns of survival. They found that winter rainfall has a major effect on the survival of young tortoises. Should the climate become more arid as seems likely (14), survival of populations of Hermann's tortoise is likely to decrease and extinction will become more likely, particularly if other threats are not reduced.
It is predicted that there will be dramatic changes to temperature and precipitation levels in the Mediterranean region (14). This will have as yet unknown effects on tortoise populations. A study by Fernandez-Chacon in 2011 (15) attempts to predict what effect climate change may have on Hermann's tortoises. In this study the authors used over 20 years of data to look at patterns of survival. They found that winter rainfall has a major effect on the survival of young tortoises. Should the climate become more arid as seems likely (14), survival of populations of Hermann's tortoise is likely to decrease and extinction will become more likely, particularly if other threats are not reduced.
Trade history: In the 1970s, Hermann's tortoise was the second most traded tortoise species in the UK, after the spur-thighed.
Directly after the listing of Hermann's tortoise as an Annex A species (ban on wild-caught individuals), trade in Hermann's tortoise became negligible. Recently though, trade has resumed, with captive breeding programmes having sprung up around Europe (figure 5). It now appears to be increasing, perhaps because captive breeding facilities have become more efficient with an increased number of breeding individuals. However, it is also possible that the trade is being supplemented with wild caught individuals. Although there are many tortoise breeders in the UK, the majority of tortoises in trade will have been imported. |