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A SUMMARY OF CLIMATIC AND BEHAVIOURAL DATA ON GEOCHELONE SULCATA
Published in French in ‘La Tortue’ 1988 – 2006
Translation by Jenny Robbins for the Tortoise Trust. www.tortoisetrust.org
This data is an unedited summary of raw data contained a series of comprehensive articles published in French in the journal ‘La Tortue’ over many years. This is uniquely reliable data in that it was written and compiled by people who have worked in the field with this species for more than two decades. The full articles are very well illustrated and contain a wealth not only of basic data, but extremely valuable commentary and first-hand observations of this species in the wild. It also paints a catastrophic picture of rapid population decline in recent years to collection and habitat destruction. There are some really interesting observations on behaviour here. Enjoy.
(1) LA TORTUE No 9 OCT 88
- SEE MAP
- Arid habitat (45 Celsius in shade in April) far from fresh water sources, difficult to access, does not rain every year.
- Lives in Rameroue area in the FERLO
(2) LA TORTUE No 10 FEB 89 JEAN-PIERRE POUVRAEU
- Males can weigh 100kgs, females 60 max
- Mating can occur several times a day & several days running with the same female
- Can lay several times in several days in different places, probably to foil predators
- The female lays her eggs using her back legs that she bends to soften the landing of the eggs Using them like a funnel. She then covers them with 4-5 cms of earth. Then she wets the nest with water that she has on either side of the cloaca. It appears that this is important for the eggs themselves. She then lays 2 or 3 more on the surface of the nest and then blocks up the nest completely and waters again. May be a ploy so that predators take the few and don’t look any further.
- At birth measure 20mm long x 47mm wide in general.
- Growth is very rapid. Great difference in size of juvenile and full adult size
(3) LA TORTUE No 10 JUNE 1989 J.P. POUVREAU
- SANDY REGION, NEARLY DESERTED, SCATTERING OF TREES AND DRY GRASSES.
- Between Dec & March violent winds & sand storms, especially in Feb & March windiest months in Senegal. Also coldest period with very low temps at night.
- In April can be 40 Celsius in shade at midday in the Ferlo.
- Sulcata active for a great part of year.
- When period of wind stays hiding in hole
- From Dec-April can be seen in daytime
- From May-Sep, very hot period, goes into semi-estivation. In day stays in hole protected from sun. Hole can be 5m deep. Comes out very early or even at night to feed.
- Instinctively digs very deep burrow. It is primarily a place of protection & estivation.
-This burrow, necessary for its survival, has unfortunately an inconvenience it makes the tort easy to find both by animal predators & humans.
- Adult can weigh between 40-100kg and due to this bulk the animal shifts heaps of sand, leaving tracks like jcb caterpillar marks. This makes his burrow easily identifiable especially as it is often located at the foot of a tree.
- This excavation also attracts carnivores and poisonous snakes (naja and desert viper)
- Jan 1989 temp variation from 12 Celsius at 7 am to 35 Celsius at 3.00 pm.
(4) LA TORTUE No13 JAN 1990
-Males have similar behaviour as Gopherus when mating. Both species Fouisseuses and habitat & way of life similar & morphologie.
-The males “Fight for the Lady†One male on seeing another coupling with a female will rush forward regardless of spectators and separate the “loversâ€. He will provoke the other male and a fierce fight will ensue. The highly developed forked gular makes for resounding jousting. With locked gular they violently try to turn each other over. This combat most often ends with one of the males either being overturned or running away.
- Very often in the wild this will lead to the death of one of the combatants. This would appear to be a “waste†for the species, a sort of behavioural error. The gular is often so long and developed that it actually impedes the animal. The tortoise can only carry its head on one side of this fork or the other. This would seem to be a negative adaptation hindering the animal. Strange evolution?
(5) LA TORTUE No23
- Sulcata live in band 500 kms wide crossing central Africa from W to E.
Mauritania, Senegal, Mali, Nigeria, Tchad, Sudan & Ethiopia (Latitude 20 Degrees north)
- In Sengal lives between Gambie and Senegal rivers
- In Ethiopia seems to be partially eradicated
- In Sudan possible that relatively large populations survive
- Tchad, Nigeria & Mali has become rare, no longer seen along Niger
- Mauritania very few - climate more Sahara than Sehal
- Only place where found in original biotope is in triangle between RICARD TOLL, DJOURBELL and HAYE on Mali border
- About 30 specimens were released at RESERVE DES SIX – FORAGES also at RESERVE DU DOLI
- At slightest alert they rush to their shelter &burrow as fast as they can to bury themselves
- Live in vast territories with a low density per km2
- Calculated maximum of 10,000 specimens in whole territory
- Species which digs the deepest burrows, some more than 4 metres long burrow with fore paws with short, very rapid jerky movements
- Live like hermits in subterranean “palaces†which they will sometimes share with jackals, jerboas & vipers
- Hydric qualities similar to Camel; urine in powder, capacity to drink in one go more than 15% of its body weight
- Mating impressive! Bangs, bellows, forepaws deeply “rooted†on female. Surprising violence for such an animal
- Dates and length of laying season….. Senegal seasons fairly regular, alternate btw dry & wet “winter†corresponding to our summer….wet between July & Oct. Due to this thermal regularity the laying can be widely spread out through the year and depending on the frequency of the rains, incubation can vary from weeks to several months
- Breeding in Feb/March, laying in april, sometimes also from nov to feb
- Lay about 20 eggs although large females can up to 30 this is max poss
- Eggs 40mm , 35g approx.
- Incubation: 100 days for hatchings just after first rains, but can take 5 to 6 months if thermic disturbances due to early rains
- Opportunistically omnivorous - succulents, fruits, grasses also left overs & waste, lizards, crickets, gerboas and also carrion & rooting foodstuffs
( 6)LA TORTUE No 35 AUG 1996
- Sanitary Centre at Sangalkam plus nursery for juveniles 110 animals plus 95 babies at end of july, more expected , plus Village des Tortues at Noflaye is developing.
- Typically14-21 eggs per female -40-65g (6x more than Hermann egg)
- Incubation 97-190 days - average 110
- Laying season Dec to April, 2 per female
- Hatching Jun, Jul & Aug. Juveniles arrive just before the rains which aids survival due to hydration opportunities and plentiful shoots and grasses “in naturaâ€.
- Contrary to European tortoises who lay in a hard and often clay substrate, these are laid in soft sand allowing easy exit and no need to soften ground
- The laying females were those reintroduced in 1995 from Holland, Mauritania and Paris. Animals had therefore completely adapted to new environment.
- Adults liked peanut leaves dry and not very nutritious
(7)LA TORTUE No36 NOV1996
- Sexual maturity 10-12 for males ,bit more for females
- Continues to grow rapidly until 20 years.
(8) LA TORTUE No44 NOV1998- B DEVAUX
- Appears that no longer any surviving in natural environment. Practically no juveniles found in the wild. Conservation programme to be started & monitored by gamekeepers & villagers in RANEROU village
- See map p19
(9) LA TORTUE No 48 NOV 1999- B DEVAUX interviews THOMAS DIAGNE
-Sahel means “shore†in Arabic and well describes this land between the dunes of Mauritania and the wetter southern part of the country
Sahel has varied biotopes ranging from the extreme desert aridity to the 1st savanahs of Niokolo-Koba.
- One of main roles of Sulcatas is the dispersal of seeds of local flora . Faidherbia albida, Acacia raddiana, Boscia senegalensis, Zizyphus Mauritania. They are great fertilisers – compost and the passage though their digestive system facilitates the germination of certain seeds.
(10) LA TORTUE No 49 FEB 2000 B DEVAUX
- Researching if genetic diff between Sudan sulcata and Senegal. Only visible diff is slight . Shell slightly less orange than in Senegal, Mali, Mauritania, and in Sudan greyer and more earthy: not enough evidence yet.
(11) LA TORTUE No75 NOV 2006
-Spectacularly powerful animals
- Takes dried grasses and straw into burrow as food store in dry season cf. 1904 Captain Vallier
- Known as the tortoise that cries - eyes often irritated by sand
- Most expressive and dynamic of big torts; galaps, aldbra. sulcats
- Excessively fearful, most curiosity of them, contrary to others who will hide for hours in their shells, sulcatas cannot resist putting an eye and then head out minutes after having puffed with rage at being handled, defying intruder that disturbed them.
- Probably the tortoise the closest to humans, cooperative behaviour, e.g., large male came to slap B. Deveau’s leg with gular both friendly and aggressive to show he wanted human attention, others come and will place paws in lap out of friendliness.
- Hate being manipulated
- A Cadi (researcher) says; these tortoises follow a cycle. One tortoise can live in several burrows, that several can live in the same burrow and that a tortoise can occupy a hole that it did not dig. Also they have a very precise knowledge of the countryside and the places where a certain number of burrows can be found. In the event of a landslide or the destruction of a hole by the rains, they are capable of walking 5 km to find an old burrow. With telemetric equipment it has been shown that the animal will find a precise burrow straight away, directly.
- Tortoises captive bred in Senegal at Noflaye appear to adapt to the wild but test will be if they still know how to burrow in dry season 2007. A. Cadi has reservations about the possibility of European captive bred sulcatas adapting to their original natural environment and if they can’t he questions their reproduction in captivity.
- There was release in July 06 in the reserve of Katane. The torts were fitted with radio-transmitters, students track them daily. This experiment will continue for one year to observe the ability of this species to adapt when returned to its original environment. End Nov 06 only one tort had not been found. The others have stabilized, dug holes and put on weight, indicating good adaptability. Researchers will continue to track each tort until end of 2007.
Published in French in ‘La Tortue’ 1988 – 2006
Translation by Jenny Robbins for the Tortoise Trust. www.tortoisetrust.org
This data is an unedited summary of raw data contained a series of comprehensive articles published in French in the journal ‘La Tortue’ over many years. This is uniquely reliable data in that it was written and compiled by people who have worked in the field with this species for more than two decades. The full articles are very well illustrated and contain a wealth not only of basic data, but extremely valuable commentary and first-hand observations of this species in the wild. It also paints a catastrophic picture of rapid population decline in recent years to collection and habitat destruction. There are some really interesting observations on behaviour here. Enjoy.
(1) LA TORTUE No 9 OCT 88
- SEE MAP
- Arid habitat (45 Celsius in shade in April) far from fresh water sources, difficult to access, does not rain every year.
- Lives in Rameroue area in the FERLO
(2) LA TORTUE No 10 FEB 89 JEAN-PIERRE POUVRAEU
- Males can weigh 100kgs, females 60 max
- Mating can occur several times a day & several days running with the same female
- Can lay several times in several days in different places, probably to foil predators
- The female lays her eggs using her back legs that she bends to soften the landing of the eggs Using them like a funnel. She then covers them with 4-5 cms of earth. Then she wets the nest with water that she has on either side of the cloaca. It appears that this is important for the eggs themselves. She then lays 2 or 3 more on the surface of the nest and then blocks up the nest completely and waters again. May be a ploy so that predators take the few and don’t look any further.
- At birth measure 20mm long x 47mm wide in general.
- Growth is very rapid. Great difference in size of juvenile and full adult size
(3) LA TORTUE No 10 JUNE 1989 J.P. POUVREAU
- SANDY REGION, NEARLY DESERTED, SCATTERING OF TREES AND DRY GRASSES.
- Between Dec & March violent winds & sand storms, especially in Feb & March windiest months in Senegal. Also coldest period with very low temps at night.
- In April can be 40 Celsius in shade at midday in the Ferlo.
- Sulcata active for a great part of year.
- When period of wind stays hiding in hole
- From Dec-April can be seen in daytime
- From May-Sep, very hot period, goes into semi-estivation. In day stays in hole protected from sun. Hole can be 5m deep. Comes out very early or even at night to feed.
- Instinctively digs very deep burrow. It is primarily a place of protection & estivation.
-This burrow, necessary for its survival, has unfortunately an inconvenience it makes the tort easy to find both by animal predators & humans.
- Adult can weigh between 40-100kg and due to this bulk the animal shifts heaps of sand, leaving tracks like jcb caterpillar marks. This makes his burrow easily identifiable especially as it is often located at the foot of a tree.
- This excavation also attracts carnivores and poisonous snakes (naja and desert viper)
- Jan 1989 temp variation from 12 Celsius at 7 am to 35 Celsius at 3.00 pm.
(4) LA TORTUE No13 JAN 1990
-Males have similar behaviour as Gopherus when mating. Both species Fouisseuses and habitat & way of life similar & morphologie.
-The males “Fight for the Lady†One male on seeing another coupling with a female will rush forward regardless of spectators and separate the “loversâ€. He will provoke the other male and a fierce fight will ensue. The highly developed forked gular makes for resounding jousting. With locked gular they violently try to turn each other over. This combat most often ends with one of the males either being overturned or running away.
- Very often in the wild this will lead to the death of one of the combatants. This would appear to be a “waste†for the species, a sort of behavioural error. The gular is often so long and developed that it actually impedes the animal. The tortoise can only carry its head on one side of this fork or the other. This would seem to be a negative adaptation hindering the animal. Strange evolution?
(5) LA TORTUE No23
- Sulcata live in band 500 kms wide crossing central Africa from W to E.
Mauritania, Senegal, Mali, Nigeria, Tchad, Sudan & Ethiopia (Latitude 20 Degrees north)
- In Sengal lives between Gambie and Senegal rivers
- In Ethiopia seems to be partially eradicated
- In Sudan possible that relatively large populations survive
- Tchad, Nigeria & Mali has become rare, no longer seen along Niger
- Mauritania very few - climate more Sahara than Sehal
- Only place where found in original biotope is in triangle between RICARD TOLL, DJOURBELL and HAYE on Mali border
- About 30 specimens were released at RESERVE DES SIX – FORAGES also at RESERVE DU DOLI
- At slightest alert they rush to their shelter &burrow as fast as they can to bury themselves
- Live in vast territories with a low density per km2
- Calculated maximum of 10,000 specimens in whole territory
- Species which digs the deepest burrows, some more than 4 metres long burrow with fore paws with short, very rapid jerky movements
- Live like hermits in subterranean “palaces†which they will sometimes share with jackals, jerboas & vipers
- Hydric qualities similar to Camel; urine in powder, capacity to drink in one go more than 15% of its body weight
- Mating impressive! Bangs, bellows, forepaws deeply “rooted†on female. Surprising violence for such an animal
- Dates and length of laying season….. Senegal seasons fairly regular, alternate btw dry & wet “winter†corresponding to our summer….wet between July & Oct. Due to this thermal regularity the laying can be widely spread out through the year and depending on the frequency of the rains, incubation can vary from weeks to several months
- Breeding in Feb/March, laying in april, sometimes also from nov to feb
- Lay about 20 eggs although large females can up to 30 this is max poss
- Eggs 40mm , 35g approx.
- Incubation: 100 days for hatchings just after first rains, but can take 5 to 6 months if thermic disturbances due to early rains
- Opportunistically omnivorous - succulents, fruits, grasses also left overs & waste, lizards, crickets, gerboas and also carrion & rooting foodstuffs
( 6)LA TORTUE No 35 AUG 1996
- Sanitary Centre at Sangalkam plus nursery for juveniles 110 animals plus 95 babies at end of july, more expected , plus Village des Tortues at Noflaye is developing.
- Typically14-21 eggs per female -40-65g (6x more than Hermann egg)
- Incubation 97-190 days - average 110
- Laying season Dec to April, 2 per female
- Hatching Jun, Jul & Aug. Juveniles arrive just before the rains which aids survival due to hydration opportunities and plentiful shoots and grasses “in naturaâ€.
- Contrary to European tortoises who lay in a hard and often clay substrate, these are laid in soft sand allowing easy exit and no need to soften ground
- The laying females were those reintroduced in 1995 from Holland, Mauritania and Paris. Animals had therefore completely adapted to new environment.
- Adults liked peanut leaves dry and not very nutritious
(7)LA TORTUE No36 NOV1996
- Sexual maturity 10-12 for males ,bit more for females
- Continues to grow rapidly until 20 years.
(8) LA TORTUE No44 NOV1998- B DEVAUX
- Appears that no longer any surviving in natural environment. Practically no juveniles found in the wild. Conservation programme to be started & monitored by gamekeepers & villagers in RANEROU village
- See map p19
(9) LA TORTUE No 48 NOV 1999- B DEVAUX interviews THOMAS DIAGNE
-Sahel means “shore†in Arabic and well describes this land between the dunes of Mauritania and the wetter southern part of the country
Sahel has varied biotopes ranging from the extreme desert aridity to the 1st savanahs of Niokolo-Koba.
- One of main roles of Sulcatas is the dispersal of seeds of local flora . Faidherbia albida, Acacia raddiana, Boscia senegalensis, Zizyphus Mauritania. They are great fertilisers – compost and the passage though their digestive system facilitates the germination of certain seeds.
(10) LA TORTUE No 49 FEB 2000 B DEVAUX
- Researching if genetic diff between Sudan sulcata and Senegal. Only visible diff is slight . Shell slightly less orange than in Senegal, Mali, Mauritania, and in Sudan greyer and more earthy: not enough evidence yet.
(11) LA TORTUE No75 NOV 2006
-Spectacularly powerful animals
- Takes dried grasses and straw into burrow as food store in dry season cf. 1904 Captain Vallier
- Known as the tortoise that cries - eyes often irritated by sand
- Most expressive and dynamic of big torts; galaps, aldbra. sulcats
- Excessively fearful, most curiosity of them, contrary to others who will hide for hours in their shells, sulcatas cannot resist putting an eye and then head out minutes after having puffed with rage at being handled, defying intruder that disturbed them.
- Probably the tortoise the closest to humans, cooperative behaviour, e.g., large male came to slap B. Deveau’s leg with gular both friendly and aggressive to show he wanted human attention, others come and will place paws in lap out of friendliness.
- Hate being manipulated
- A Cadi (researcher) says; these tortoises follow a cycle. One tortoise can live in several burrows, that several can live in the same burrow and that a tortoise can occupy a hole that it did not dig. Also they have a very precise knowledge of the countryside and the places where a certain number of burrows can be found. In the event of a landslide or the destruction of a hole by the rains, they are capable of walking 5 km to find an old burrow. With telemetric equipment it has been shown that the animal will find a precise burrow straight away, directly.
- Tortoises captive bred in Senegal at Noflaye appear to adapt to the wild but test will be if they still know how to burrow in dry season 2007. A. Cadi has reservations about the possibility of European captive bred sulcatas adapting to their original natural environment and if they can’t he questions their reproduction in captivity.
- There was release in July 06 in the reserve of Katane. The torts were fitted with radio-transmitters, students track them daily. This experiment will continue for one year to observe the ability of this species to adapt when returned to its original environment. End Nov 06 only one tort had not been found. The others have stabilized, dug holes and put on weight, indicating good adaptability. Researchers will continue to track each tort until end of 2007.
