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Preliminary report on the Taxonomic,
Biotypic and Conservation status of the land tortoises
of Tunisia
A C Highfield
Field research assistant: L. E. King
Introduction
Little detailed work has been published on the terrestrial
tortoises of Tunisia which have generally been assumed by
most authors to be purely standard specimens of Testudo
graeca graeca LINNAEUS 1758 demonstrating little or no
regional variation from those of type locality (Oran,
Algeria) or from those of Morocco. The most important
papers published to date although providing some useful
data on distribution and conservation do not attempt to
re-examine the taxonomic status of these tortoises, nor do
they provide any morphometric data or illustrations. Field
work recently undertaken by the author suggests that a
re-examination is overdue as the tortoises of Tunisia are
remarkably different in several important respects from
those of the neighboring countries of Algeria or Libya and
may represent several unique and taxonomically separate
species or sub-species requiring a major revision of
currently accepted nomenclature.
Distribution & published records
The most important data on the distribution of tortoises
within Tunisia is that provided by Blanc (1978) which
lists by region many important centres of population. The
majority of observations are recorded in the north of the
country within the Tunisian Atlas (Khroumirie) mountain
range principally in the Teboursouk, Beja, Jendouba,
Testour, Le Kef and Ain Draham areas which are typified by
a high annual rainfall and are thickly vegetated with holm
and cork oak forestation. Further observations of coastal
and steppe habitat populations are noted in the Grombalia,
Nabeul and Kairouan areas. Additional recent data on
distribution is given by Lambert (1982 and personal
communications) who lists previously unpublished
observations in the Tunis and Hammamet regions and in the
oases of Gabes.
Other useful papers on distribution and habitat include
those by Mayet (1903) who provides good general data and
an extremely important observation on egg morphology until
now overlooked, and Mosauer (1934) who lists observations
in the Rades, Sidi bou Ali and Kairouan regions.
Historically important records of chelonians in Tunisia
are also provided by Gadeau de Kerville (1908) who records
T. graeca, Emys orbicularis and Mauremys caspica leprosa
in the Khroumirie, by M. Blanc (1935) who notes records of
T. graeca in the Khroumirie, Cap Bon, Kelibia, Sousse,
Kairouan and in the region of Tunis with additional
records of M. c. leprosa and E. orbicularis including Ain
Draham, Tabarca, Zaghouan and Grombalia. Other interesting
(but less detailed) records are provided by Boulenger
(1891) who cites T. graeca in the ruins of Zarzis, by
Konig (1892), Olivier (1896), Anderson (1892) and by
Seurat (1922 and 1927). Useful accounts of some sympatric
reptile species are also provided by Mayet (1903), Mosauer
(1934), Chpakowski and Chneour (1953), Domergue (1956-1966
and 1959), Escherich (1896), Lanza and Bruzzone (1960),
Laurens (1975), Mocquard (1895) and Thilenius (1897)
whilst Mertens (1929) describes in some detail the
herpetofauna of Belvedere Park in Tunis and that of the
oases of Gabes.
General nomenclature and taxonomy of north African
terrestrial tortoises
For many years it was assumed that all terrestrial
tortoises in north Africa with the exception of Testudo
kleinmanni LORTET 1887 which occurs in Egypt and Libya
belonged to the nominate subspecies Testudo graeca graeca
LINNAEUS 1758 (terra typica = Oran, Algeria). Common
synonyms include Testudo mauritanica DUMERIL & BIBRON
1835 and Testudo ibera PALLAS 1814 (actual type locality =
Georgia, U.S.S.R and which does not occur in north
Africa). For a brief analysis of the morphology and
history of the holotype of T. g. graeca see Highfield
(1990a). Recently the present author has also demonstrated
that at least one other species also exists in the region,
Testudo whitei . The former is the largest species
of Mediterranean land tortoise so far known to science,
routinely reaching an adult body mass of over 3kg and a
straight-line carapace length of 250mm by 25 years of age
with the largest individual recorded measuring 292mm and
weighing 4.550kg at 30 years of age (Highfield, in press).
It should be noted that field workers observing these
animals have almost invariably assumed that specimens of
Testudo whitei ere actually very old specimens of Testudo
graeca graeca L. 1758 (or earlier, specimens of Testudo
marginata SCHOEPFF 1792; e.g see Gray, 1870 and Gervais,
1836)
Mention should be made in this context of the alleged
sub-species Testudo graeca terrestris FORSKAL 1775 which
according to Wermuth (1958) is found in Libya. Recent
taxonomic studies have demonstrated this attribution to be
entirely erroneous and that it definitely does not occur
anywhere in North Africa (Highfield & Martin, in
press). There are in any event no alleged records of this
tortoise for Tunisia.
The current taxonomic status of north African land
tortoises is therefore cited as follows;
- Testudo graeca graeca LINNAEUS 1758
- Testudo whitei BENNETT 1836
Notes on measurements and photographic records
During field work it is important to record as many details
as possible of individual specimens examined. Some of these
details are of peripheral taxonomic value (although they may
prove of considerable value in other study areas such as
growth and development), but others are of primary taxonomic
importance; the following listed measurements are of special
diagnostic value:
- Straight-line carapace length (L)
- Carapace length over curve (LoC)
- Median body width (Mw)
- Maximum width at marginals (MwM)
- Body width at M1 - M2 (front) marginal suture (Fw)
- Maximum carapace height at V2-V3 (Ch)
- Weight (W)
- Plastral suture lengths P1, P2, P3, P4, P5 and P6.
- Post anal gap (PaG); (of prime importance in female
specimens)
A more complete set of measurements will also include length
x width of V1-V5, M1-M11, supracaudal, nuchal, C1 - C4 and
on the plastron dimensions of the intergular, gular,
humeral, pectoral, abdominal, femoral and anal plates.
It is absolutely essential that all specimens are
photographed both in colour and black and white; the
following views will be found most useful;
- Directly from above
- Plastron
- Head-on frontal view showing V1
- Rear view towards showing V5 and supracaudal
- Side view showing marginals and costals
- Close-ups of head from above and sides
- Frontal close-up of head showing beak
It is also good practice to photograph each animal exactly
as found in situ giving general views of the environment and
location. If possible a shade and open temperature reading
should be taken together with data on relative humidity.
Where eggs are to be recorded a length, width and weight
should be taken; these should also be photographed against a
25mm graduated scale.
Finally, it is vitally important to note that great care
must be taken not to assume that all very small tortoises
are juveniles or that all large examples are of great age -
by 15 years of age a Testudo whitei BENNETT 1836 will often
surpass a 50 year old specimen of Testudo graeca graeca
LINNAEUS 1758 by over 200% in both length and weight. With
practice, it becomes relatively easy to recognise genuine
juveniles. Until this skill is acquired however, mistakes
often occur.
It is interesting to note also that according to Flowers
records (1944) a juvenile T. whitei BENNETT 1836 exceeds the
dimensions of even a fully grown adult Tunisian tortoise of
maximum attainable size from the Sidi Kalifa region by 9
years of age. These statistics are confirmed by independent
records in our possession.
The value of comparative data
Each population must be examined and recorded as a
separate entity; data collected from diverse populations,
if integrated at random, often leads to inaccuracy and
confusion; a good example is the inclusion of data from T.
whitei in many reports on Algerian T. graeca graeca. This
problem can be avoided by providing each individual
specimen or record with a unique identification code
thereby allowing every set of data to be sorted or
re-sorted later according to revised criteria and with a
permanent record of exactly where the specimen referred to
was found. Without location data records are of extremely
limited value.
By keeping accurate records of where specimens were
located it becomes much easier to draw valid conclusions
as to the presence of unique localised characters,
regional clines, or make decisions which may ultimately
affect the genetic integrity of a population, e.g
repopulation by captive breeding or the release of
transported or previously captive animals.
The value of accurate records from clearly identifiable
sites cannot be overestimated.
It should be noted that the practical uses of such data
are considerable; for example it becomes possible to
identify with a high degree of accuracy the precise area
from which a tortoise originated by comparison of its
characters with data from others on file - this has
obvious applications in conservation enforcement and
wildlife protection, making the detection and prevention
of illegal trading or exportation very much easier and
more effective.
We are confident that the taxonomic characters and
indicators of individual populations within Tunisia are
sufficiently diverse to permit correlation of translocated
specimens to specific sites with a very high degree of
accuracy.
Observations of tortoises 25/12/89 to 30/12/89 in
Tunisia
Locality records
- Between Nabeul (7km) and Grombalia (21km) (25/12/89)
adult females; 118mm (L) X 104mm (Mw) and 130mm (L) X
107mm (Mw)
12.45 to 1.20 pm both feeding on sun exposed slopes.
Soil temperature 27.6 oC, shade temperature 23.2 oC.
Relative humidity circa 55%.
- Sidi bou Ali (26/12/89)
1 adult male; 113mm (L) X 79mm (Mw)
This tortoise was examined in a house in the village
where it was being kept for utilisation as a medication.
The tortoise had been purchased by the inhabitants from
a mobile door to door salesman who had recently passed
through the area.
- Enfidaville (26/12/89)
1 adult male; 112mm (L) X 75.5mm (Mw)
This specimen was being kept as a pet in a large walled
garden. Morphologically identical to Sidi bou Ali
example.
- Enfidaville (28/12/89)
1 adult female; 134mm (L) X 99.5 (Mw)
1 adult male; 122mm (L) X 83mm (Mw)
Pair of pet tortoises kept in garden. History of
successful captive breeding. Both specimens clearly of
identical race, but different from previous specimens.
- Forest of Sidi Kalifa (28/12/89)
1 adult male; 105mm (L) X 82mm (Mw)
Observed grazing at 11.00 am. Ground temperature 14oC,
shade temperature 18.5oC. Relative humidity 60%.
Altitude approximately 400m.
This specimen morphologically identical to specimens 2
and 3 (above). Clearly these also were collected from
this locality.
- M'hadba (29/12/89)
2 adult females; 138mm (L) X 101.5 (Mw) and 134mm (L) X
95mm (Mw)
2 juvenile females ; 96mm (L) X 74mm (Mw) and 67mm (L) X
87mm (Mw)
Observed in olive grove. Smallest juvenile estimated age
18 months - 2 years; larger juvenile estimated age 3
years. All 4 specimens were identically marked and were
very different in general appearance from the previous
specimens observed.
- Nabeul (30/12/89)
1 small juvenile female; photographed but not measured.
On display and being offered for sale (10 TD) from
street sellers stall alongside mounted scorpions and
other natural history objects. When questioned,
stallholder claimed that many were available. When asked
who purchased them, he became evasive but eventually
stated that tourists were the intended customers and
that they were being purchased as pets for illegal
export to Europe. At 10 TD only a foreigner would be
likely to purchase as this price is very excessive by
Tunisian standards. When this was pointed out the
stallholder explained that tortoises were in demand by
foreign tourists as 'Les tortues grecque' were no longer
available legally in Europe.
- Hammamet (30/12/89)
4 adults; photographed but not measured.
Observed being offered for sale from a small crate
outside a shop in the medina. Price asked = 20 TD each.
Shop owner questioned and replied that he was aware that
sale and export from Tunisia was illegal, but that he
could make a large profit from selling tortoises to
tourists. English tourists nearby observed us examining
the tortoises and assumed that we were interested in
making a purchase; they then approached us to inform us
that they believed export or sale of these animals in
Tunisia was illegal as they had seen the educational
posters issued by the Department of Forests which are
displayed in some hotels.
- Hammamet (30/12/89)
28 very small juveniles (dead); 55mm - 80mm (estimated).
On sale in shop called 'Le Souk D'Art Artisanal
D'Hammamet'. Preserved and coated with varnish. Price
asked = 6.500 TD each. This shop accepts Access, Visa,
American Express and Diners Club credit cards. Other
native Tunisian fauna also on sale including scorpions.
Estimated age of specimens approximately 1 to 6 years of
age. All apparently collected locally and killed
specifically to supply the illegal 'souvenir' export
trade.
Note on exploitation
Despite our observations of the encouragement of illegal
export of tortoises by a minority of traders, it is clear
that the Tunisian authorities are promoting effective
educational efforts directed at discouraging such illegal
and destructive activities. The poster dealing with the
export of prohibited flora and fauna issued by the Direction
General des Forets does illustrate tortoises and other
reptiles in addition to birds and prohibited plants . This
is obviously read and understood by many tourists as
confirmed by our encounter in the medina. All of the dealers
we spoke to were also fully aware that they were engaged in
an illegal and prohibited trade which was contrary to the
wishes of the Tunisian government and Department des Forets.
Regarding the local utilisation of individual tortoises by
villagers for medicinal purposes (the flesh is used for
stomach illnesses and the blood is also sometimes used as a
cure for warts), we feel that this is less of a threat than
the commercial illegal export trade which in our opinion
does pose a serious danger to some already depleted low
density populations. The souvenir trade in dead juveniles
has a particularly destructive ecological potential and
should definitely be suppressed.
We have also received reports of identical trade in other
areas of the country; live juvenile specimens were on sale
in the summer of 1989 in the medina of Sousse and preserved
specimens similar to those observed by us in Hammamet were
on sale in El Djem (J. Bruekers, Netherlands. Personal
communication).
Ministry of Agriculture directive (Art.6 alinea 5) of 2nd
August 1973 prohibits the collection, buying, door to door
trading, selling and export of Tunisian tortoises.
Note; Blanc (1978) quotes then current prices of tortoises
in Tunisia as between 50 and 120 millimes - compare to the
illegal dealer in Hammamet medina now asking 20 Dinars.
Morphometric data on recorded specimens
For the purpose of this preliminary report specimens of
only one of the 4 distinct and readily identifiable
populations observed will be described for the purpose of
comparison with Testudo graeca graeca L. 1758 and T.
whitei BENNETT 1836. In order to make clear the comparison
male specimens only are described.
This particular group was selected for special study for
the following reasons;
- We already had computer data on file for specimens
conforming exactly to this groups characters - this data
was obtained from tortoises exported from Tunisia via
the bulk pet trade before the present conservation ban
on export was adopted.
- This data is invaluable in that it provides records of
lengths and weights over a period as long as 30 years
for some individual specimens thus permitting an
unparalleled study of growth and development for the
population type.
- We have several living specimens of this tortoise in
our reference collection in England which we have
carefully monitored for some years; these animals are
all survivors of the bulk pet trade which were donated
to us by pet keepers no longer wishing to retain them.
- We have an exact locality in which tortoises of this
type can be found in their natural habitat (Forest of
Sidi Kalifa).
- e) Our museum reference collection includes
osteological material for this group.
Morphological observations
Specimens 1 and 2 measured in Tunisia. The measurements for
T. g. graeca LINNAEUS 1758 and T. whitei BENNETT 1836 are
averages obtained from a sample of over 50 specimens
recorded on our computer. Specimen number 3 is a tortoise
identical in appearance to the Sidi Kalifa specimens but
which has been in captivity in England for 20 years. This
specimen is believed to be circa 45 years of age and visible
growth has now ceased. Specimens 1 and 2 both displayed some
slight evidence of continuing growth but were definitely
mature adults with an estimated age of circa 15-18 years.
Our records contain further data on several other examples
which are identical to specimens (1) and (2) observed in
Tunisia in all important diagnostic characters. Of these,
one is of special interest as the tortoise is obviously of
very extreme age and has a confirmed history in captivity
in England of precisely 31 years. Comparison of scute
surface deterioration with other examples of Testudo spp.
of confirmed age suggests an estimated age of between 70 -
80 years for this specimen.
The primary measurements of this very ancient tortoise are
as follows;
L = 120mm, Ch = 55mm, Mw = 75mm, MwM = 80mm. The body mass
is 360g.
There has been no measurable growth in any parameter since
the tortoise was obtained by the present keeper 27 years
ago. Comparison with specimens (1), (2) and (3) suggests
that we can therefore conclude that 120-125mm straight
line carapace length probably represents the maximum
dimensions attained by males of this race even as very
mature adults. This compares with a measured absolute
maximum recorded of L = 188mm, Ch = 102mm, MwM = 118mm for
Moroccan-Algerian T. graeca graeca and average carapace
lengths of circa L = 155mm for the same species (Highfield
& Martin, 1989; Lambert 1982 & 1983).
In comparative dimensional terms, the tortoises of Sidi
Kalifa are slightly larger than Testudo kleinmanni LORTET
1887 (Flower, 1933). As such they represent one of the
worlds smallest Testudo spp.
Carapace scute measurements
Further dimensional statistics obtained from the Sidi
Kalifa tortoises are as follows;
Supracaudal; 30.5 X 18.5 & 29 X 18.5
The supracaudal shape is not consistent with that of T. g.
graeca from the type locality of Oran, Algeria but is
significantly more projected beyond the marginals in a
manner which somewhat resembles that found in T.
kleinmanni LORTET 1887.
Frontal vertebral scute
The f.v.s is also not consistent with a diagnosis of T. g.
graeca (Highfield, in press), being significantly less
round and more angular.
Beak construction
Bi-cuspid rather than tri-cuspid as T. g. graeca
(Loveridge & Williams, 1957).
Adult Skull dimensions
Skeletal and cranial analysis of this tortoise is at an
early stage of research, but some useful observations
already made include;
- Basal length = 25mm
- Quadrate width = 18mm
- Supraoccipital - Basioccipital separation = 5mm
- Frontal width = 7mm
Full details of comparative cranial osteology will be
published subsequently.
Suprapygal osteology
The suprapygal construction of the Tunisian tortoises
differs completely from that defined as in accordance with
T. g. graeca LINNAEUS 1758 (Loveridge & Williams,
1957).
In the Tunisian specimens there are two suprapygals, the
anterior being the largest and enclosing the posterior
between two symmetrical posteriorly directed rami; the
posterior suprapygal bone semi-oval on its anterior face.
In T. g. graeca L. 1758 there is a fused suprapygal
sometimes laterally divided by a straight transverse
suture. The rear facing horns (rami) are absent. This
suprapygal pattern is considered general for Testudo as a
whole, including T. ibera PALLAS 1814 from eastern Europe.
General notes on osteology of the carapace
Typically alternate octagonal and quadrilateral anterior
neurals; xiphiplastra hinged; two suprapygals as described
above.
Plastral markings
Bour (1987) has demonstrated the importance of plastral
markings in taxonomic diagnosis; however, in the case of
T. graeca it has usually been assumed that great
individual variation occurs. This view is not shared by
us. In all cases we have found that variation within
separate populations or species is very slight. In the
case of the Tunisian tortoises there are major differences
between the Grombalia (Cap Bon) population and the Sidi
Kalifa population. More specimens from both
locations need to be studied, but it is likely that these
differences will prove consistent.
Parasitology
Microscopic examination of a faeces sample taken from one
of the Sidi Kalifa tortoises revealed a zero nematode
count; a very low flagellate and ciliate count and no
evidence of additional intestinal parasites. This is in
contrast to French T. h. hermanni studied by Bruekers
(1986) where nematodes were very common.
The sample also revealed a relatively high intake of grity
silicate material and a high dietary fibre intake.
No external parasites (ticks, etc.) were noted on any
specimen examined.
Carapace condition
One specimen was observed with severe crushing damage to
the marginals and costals (M' Hadba, adult female). These
injuries appeared most likely to have been caused by
dropping or by vehicle impact. The tortoise was in
otherwise good health and feeding normally. Another
specimen (Grombalia) had suffered carapace damage
consistent with having survived a fire. There was no
evidence of carapace malformation due to congenital or
dietary causes on any specimen examined.
Egg morphology
It has often been assumed that the eggs of the various
races and species comprising the homogenous grouping
generally referred to as 'Testudo graeca' are of identical
construction. Where differences have been noted these have
usually been attributed to individual variation. In fact
each species group within what has generally been regarded
as the 'graeca' complex produces a very characteristic
size and shape of egg with a similarly characteristic
clutch size. Although a wide variety of egg forms are
encountered the range of individual variation within each
species is surprisingly small - the eggs may therefore be
usefully employed in taxonomic diagnosis.
The size, shape and weight of tortoise eggs from specified
species have rarely been studied in detail. In particular,
studies relating to Testudo graeca have tended to include
data from races other than the true Testudo graeca
described by Linnaeus in 1758 and based upon the holotype
of Edwards, 1748. i.e, most studies have randomly grouped
egg data from what were previously regarded as sub-species
of Testudo graeca or from unrecognised forms, thus
obscuring the very real differences which actually exist
between the various species in their 'pure' forms (e.g see
Cooper, 1983 and Smith, 1985).
One of the most significant and important findings to
emerge in this present study was the alleged minute
dimensions of the eggs of some Tunisian tortoises; we were
repeatedly shown drawings of eggs which were very much
smaller than anything we have previously encountered in
any land tortoise. Unfortunately, due to the time of year
of our visit, no actual egg material was available for
examination.
Habitat and biotype
It is obvious that Tunisia offers an excellent range of
habitats which are very well suited to the requirements of
terrestrial tortoises and which are capable of supporting
high density populations; furthermore, most of these
habitats are well managed and many are under the direct
control of the Direction General des Forets.
The main threat from development and industrialisation
concerns the coastal populations which are also under
threat from tourist exploitation. These populations should
therefore be considered as at highest overall risk. Most
inland sites appear reasonably secure from habitat loss
due to development and there is definitely less of a
threat from collecting for the tourist souvenir trade.
There are obviously some localised exceptions to this
general observation however.
General biotypes of Tunisian tortoises
Tortoises are most often found in grazing and pasture
land, on sunny but well vegetated undulating slopes, among
rocky forest verges and to some lesser extent in olive
groves and traditionally managed agricultural zones.
Tortoises are much less common in areas of intensive
agriculture.
Tortoises are not common in arid zones or found at all in
desert regions, other than in oasis microclimates.
Preferred humidity range would appear to be between
50-60%. Lambert (1983) suggests that limiting factors in
the distribution of north African land tortoises include
minimum mean annual rainfall and vegetation. In Morocco
Lambert notes tortoise records in areas where the mean
annual rainfall (P) = 1062mm - 1112mm. In Tunisia,
especially high density populations are noted in the
Khroumirie mountains (Ain Draham, Teboursouk etc.), one of
north Africas areas of highest annual precipitation.
In very hot weather or in cold winters the tortoises
retreat under rocks or hide in thick thorny bushes. In
mild winters the tortoises of the coastal zones do not
hibernate. The egg laying and mating periods of the
mountain tortoises are later than those of the coastal
plain and hill populations.
Altitude range is 0-800m (Blanc, 1978). In December we
found some tortoises at 400m which were still active and
feeding, but further inland tortoises at 500m were not to
be found. According to local observers, all of the
tortoises had retreated under the rocks for the past 6
weeks and were expected to emerge again in February, March
and April. In these locations we recorded ground and shade
temperatures of 12C and 14C respectively at 12.00 a.m.
Vegetation in these same areas was more sparse, mainly
Opuntia, Mandragora officinarum and similar species.
In coastal sites and in the Cap Bon tortoises were found
on gentle rocky slopes among very lush vegetation; some
sympatric plant species included Opuntia, Leontice
leontopetalum, Lupinus spp., Genista spp., Cistus spp.,
Cyclamen spp., Convolvulus spp., Plantago spp., Arisarum
vulgare (plentiful), Tulipa spp., Taraxacum spp.,
Tamaricaceae spp., etc.
In every location we found tortoises the ground was light
in texture but not completely sandy; the soil was
invariably populated with a thick carpet of plants many of
which are recognised food plants of the tortoise.
RECOMMENDATIONS & CONCLUSIONS
Exploitation and illegal export
Educational efforts directed at preventing tourists from
purchasing tortoises or objects derived from them for
illegal export need to be continued and increased; it
would be advantageous if all hotels displayed posters and
had publications available listing prohibited items and
explaining the need for conservation of Tunisias unique
flora and fauna. The assistance of the tour operators
could also be enlisted in distributing such material. More
information at Airports would be especially useful.
The activities of street sellers and souvenir shops in
tourist areas need to be subject to continual monitoring
to prevent violations. Enforcement action against
offenders would have a useful deterrent effect.
Habitat
The impact of land development and agricultural usage on
tortoise populations needs to be further studied.
Genetic integrity of populations
It is clear that there are massive differences between the
genetic make-up of certain individual populations - even
among those which may be in relatively close proximity to
each other.
This feature urgently requires additional research.
In the meantime, until more is understood of the genetic
relationships of the various populations the artificial
movement of tortoises between different sites should be
strongly discouraged.
No captive breeding releases should be made for the same
reason unless their genetic descent can be traced with
certainty to the proposed release site.
This finding also indicates that the protection of
individual sites and populations may require a much higher
conservation priority than is currently accorded.
Taxonomy and nomenclature
The tortoises of Tunisia are not identical to the
tortoises of Morocco or those of the type locality of
Testudo graeca graeca LINNAEUS 1758 in Algeria.
The conservation implications of these findings are
profound and may require extensive revisions of currently
accepted nomenclature and/or diagnostic criteria at both
species and genus levels.
FURTHER RESEARCH PROPOSED
Further work is required to establish the following;
- Average comparative clutch sizes and egg dimensions
from each population group.
- Hatchling size and weight, plus data on comparative
early phase development.
- Skeletal variations between populations; we would
stress that this work should be done without recourse to
taking specimens for killing in order to obtain data.
Adequate biological material is available by other
means, e.g utilisation of seized or confiscated
'souvenir' specimens etc.
- Seasonal activity pattern recording. Much more data is
required on comparative mating, nesting and hatching
periods for example in mountainous, coastal and steppe
habitats.
- Population stability. Long term monitoring required.
- Food chain interaction with other species, e.g
carnivorous mammals and avian predators. Nest site
damage and hatchling predation rates.
- Environmental data. e.g how activity is affected by
weather, temperature and humidity etc. Are there
differences between individual population types?.
External morphology suggests that evolutionary
environmental adaptions may have occurred at certain
locations.
- Average longevity and dimensional statistics. Much
more field data is required.
- More data is required on hibernation activity and
behaviour in the wild of the various populations -
especially comparative data between the southern and
northern populations and between coastal and mountain
region populations.
- Transit of individuals between populations; more data
required. A tracking system might be worth
investigating. Combined with systematic data recording
and marking this should provide a good deal of useful
information.
- Dietary intake; more information required to establish
precise dietary preferences and food value averages.
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