Homeland news & views

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AldabraNerd

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In support of Aldabraman's long-going thread on his captive herd, I'd like to use this thread to share views & such about the Aldabra giant tortoises in their homeland, the Aldabra Atoll, with you all. I'll do my best to answer nerdy Aldabra tortoise ecology questions (wild ones! -I haven't got the first clue about captive giants!).

Earlier this year, I spent a bit more than two months on the atoll, working on many different things - most of which were centered around the gentle giants. The atoll is huge, some 30x15 km in size, with a large central and shallow lagoon. A good idea of size: Manhattan would fit in twice in the lagoon.

And here is a view of a large male tortoise on the island of Picard, the third-largest of the four main islands in the atoll. The tortoises on Picard and on Malabar in general grow to the largest sizes.
 

Badger

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RE: Homeland news & views

Wow! Thank you so much for willing to share information and knowledge of the atoll! There has been questions i always wanted to ask about their native environment.

1) what is the daily and yearly range in terms of temperature? How hot and cold does it get?

2) any plants on the atoll that seem to be their favorite?

Thanks so much for sharing!!!
 

AldabraNerd

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RE: Homeland news & views

Badger said:
1) what is the daily and yearly range in terms of temperature? How hot and cold does it get?

2) any plants on the atoll that seem to be their favorite?
Hi Badger - the climate is very tropical/warm (from 25-30 up to 35-40 degrees C, with night temperatures a bit lower), but not always wet - there can be very dry periods of several months without rain. From April-ish to October-ish, strong south-easterly winds blow a lot of the time.
More info can be gleaned from the abstract of this old paper:
http://adsabs.harvard.edu/abs/1971RSPTB.260...67F

Vegetation varies a lot across the atoll, and the tortoises eat many different plants. They really love most plants in the pea family (Fabaceae), possibly because their leaves are often rich in nitrogen (which can be a limiting resource in the diet of herbivores). I'll try to find & post photos of them munching on plants as I go along. I brought back home around 11,000 photos - probably 40-50% of which are of tortoises :D
 

Yellow Turtle

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Now now, more pictures please of the aldabra in their native island :D

Watching a pet show in my city today, 1 stan selling like 8 aldabra cb hatchlings. And I really want to adopt like 2 of them, very nice looking, smooth and high dome if not for the price :p
 

wellington

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This is going to be a great thread. Thank you for taking the time. Besides the questions Badger asked, I also have a couple.
1-the one in the pic is brown. Are they mostly brown or black over there? Most in the States seem to be more black
2-other then plants, grasses, etc. Do you see them eat anything else?
Thanks again
 

Tom

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I'd really like to know more about what you are studying too. We are all like sponges just dying to soak up any info you can share with us. This is an extremely rare opportunity for us, so please forgive our eagerness.
 

ALDABRAMAN

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Tom said:
I'd really like to know more about what you are studying too. We are all like sponges just dying to soak up any info you can share with us. This is an extremely rare opportunity for us, so please forgive our eagerness.
I am very excited about this thread, Thank you so much! I will probably be your #1 fan! lol!
 

AldabraNerd

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wellington said:
1-the one in the pic is brown. Are they mostly brown or black over there? Most in the States seem to be more black
2-other then plants, grasses, etc. Do you see them eat anything else?
Thanks again
The colour of the torts on Aldabra is a very interesting topic; it differs between islands - but so do other traits. Hard to say what varies depending on what else. On Picard Island, there is a big size difference between males and females; males are often brownish, whereas females are often dark grey - blackish. Here's a photo; male probably around 90 cm straight plastron length:


On eastern Grande Terre, where tortoise densities are highest, they are quite a bit smaller, and have a more uniform coloration. Here's a photo from one of the 'tortoise turfs' - heavily grazed, species-rich grasslands - with a herd of tortoises (don't you just love those two words together?! -it blew me away when I first saw it!). As you can see, all torts here are similarly coloured (& more or less similarly sized; the sexual dimorphism is much less obvious here):


Here a tortoise on its home turf (heh..) - doing what it does best: keeping the grass down to world-class, golf-course standard (Aldabraman, I bet your enclosure looks the same!). The photo was taken with my 300mm lens, lying flat on the ground from about 6-7 m away - as you can see, it is very flat & cropped indeed:


Ok, 4 down - only an estimated 4,996 to go! :D
 

AldabraNerd

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Not all of the 100,000 torts have names. But this one does: Toby (or The Tobster) - a wonderful, large, friendly male. Easy to recognise from the nuchal scute, raised into a wee nubbin'.

Toby hangs around outside the research station and the huts where people live while working on the atoll, keeping our grass short. Here he is, enjoying the very last rays of the sun before going to sleep (ahh, sleeping tortoises! Cutest thing in the world).


The sun during the noon heat is too hot for the torts to handle, so they seek the shade. If you're on a stretch of empty, grassy coast, where the only shade within 300 metres is a shrub, you better not get there as the last one. Maybe that's what the one in front did - and now he's only a shell of his former self:


In other places, there are larger trees, that provide shade for plenty of tortoises - and a very ecstatic, happy version of yours truly (it was my first day on the far eastern end of Grande Terre, near Cinque Cases). What a place to eat lunch... :tort::tort::tort::tort:
 

tortadise

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Just brilliant. Would love to eat lunch, dinner, snack, tea, sit, all the time under that tree witht them.
 

Masin

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RE: Homeland news & views

tortadise said:
Just brilliant. Would love to eat lunch, dinner, snack, tea, sit, all the time under that tree witht them.
Agreed!
What beautiful pictures!! Like everyone else said CAN'T WAIT FOR MORE!!
 

ALDABRAMAN

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:) Fantastic info & photos!

* Can you share what the lowest temperature (f) you have seen at night?

* Can you say if the sex of an aldabra is determined by genetics or incubation temperature?

* Do you notice any difference in the fertility levels between the more populated herds? / or within the herds that have a more plentiful food source?
 

Blakem

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RE: Homeland news & views

Wow, what a wonderful experience it must be to be able to do this. I bet you have many stories to tell others.

If I was a whizz at science, this would be a wonderful field of study. Thanks for the post.
 

Hasselhound

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Thank you for sharing your experiences and pictures, Aldabranerd! I can't get enough!!

Kathryn
 

kanalomele

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Wow! I'm with everyone else. Thank-you so much for sharing your experience with us, and I can't wait for more pics!
 

Badger

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RE: Homeland news & views

Thanks so much for the information!!!!
 

AustinASU

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:) bucket list must, i would love to take part doing research there....just amazing! Are there a way to do this for college thesis?
 
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