Question on diversity in Leopards

[Alaskamike]

I have been studying up a bit on Leopards and wonder if anyone can shed light on this question from a keeper / hobbiest viewpoint. There are several accounts of tremendous size and growth differences even within the same clutch feeding same diet. Even a few 2-4 yo that have barley grown.

Has anyone experienced this.... Or have a possible explanation? Thanks. Mike.

 

[wellington]

There is many speculations on reasonings. I don't think anyone can know for sure. @Tom is one member that has raised many of the GPP leopards and I'm sure has probably seen this. He may have a better explanation of the why's.

 

[Tom]

The easiest way to explain this is to point the finger at how the babies were started. To this day most babies are started way too dry and dehydrated and this stunts and greatly slows their growth, but that is not the whole story...

For the past several years I have been raising various groups of tortoises. All started from tiny brand new hatchlings, or hatched myself. All groups are housed together, fed the same things and have the exact same routines. In ALL groups some grow much faster than others. Same food, temps, soaking routine, lighting, genetics, water, substrate, sunning routine, etc... We are talking about clutch mates with the same mother and father started from eggs in the exact same way. Perfect example: Tuck and Trey from the "End of Pyramiding" thread. Tuck is a male and at 4 years old is about 22 pounds. His sister Trey is closer to 35. Usually the males grow much faster than the females. So why is this? In a word: Appetite. Tuck will walk over to the food tray, eat for a bit, and then walk away leaving some food behind. He does this when there is no other tortoise in sight and when sharing the tray with one or more of the big girls he lives with. Trey, by contrast, will sit there and stuff herself until the tray is empty and picked clean of the smallest scraps. They have both always been this way. I see the same thing in all my other groups. The biggest fastest growers are (not coincidentally) also the greediest, and most eager to eat of the bunches. The same big ones are continually the first ones to the food trays, and last ones to leave the food trays.

Your question has been my latest unanswerable tortoise question: Why do some simply have more appetite than others, even when all environmental and dietary parameters are completely equal?

 

[Yvonne G]

It might also have to do with the fact that leopard tortoises here in the States are all mixed up. In Africa, the larger leopards grow in certain areas of Africa. When imported to the States, there is no longer the geographical barrier, and they are all interbred. So some of the larger tortoise genes are mixed in with the smaller tortoises.

 

[Alaskamike]

The genetic mixing is very likely. We are many generations into captive bred now. And with restrictions on imports we are not getting any more of the large ones to breed together from the most Southern areas of Africa.
Even initially it was mostly the smaller varieties that were imported.
The food consumption issue is also interesting. Do some eat more because they have bigger appetites ? Or do they have bigger appetites because they are growing faster with different genetics. I've only seem this with Leopards , but may occur in others as well.

 

[Tom]

The genetic mixing is very likely. We are many generations into captive bred now. And with restrictions on imports we are not getting any more of the large ones to breed together from the most Southern areas of Africa.
Even initially it was mostly the smaller varieties that were imported.
The food consumption issue is also interesting. Do some eat more because they have bigger appetites ? Or do they have bigger appetites because they are growing faster with different genetics. I've only seem this with Leopards , but may occur in others as well.

The mixed genes wold only be a possible explanation for differing growth rates among the "regular" leopards. It would not explain why it happens among my sulcatas, Sudan sulcatas, 4 groups of russians (total of 20), pure South African leopards, and 10 stars.

Really one could argue that a regular leopard clutch with the same mother and father should all have the same growth rates, vs. a clutch that had multiple fathers.

 

[Alaskamike]

Thanks Tom. It is helpful to have someone who is experienced in raising a good variety of torts with controlled husbandry. In every species ( people included there is extreme size variations. Even in same families with same parents. The nature / nurture question is easier to control for when we raise them. I do appreciate your efforts Tom on the hydration / humidity needs of African torts.
Other than the diets being straightened out. This in my mind is of top importance for healthy torts.
Mike

 

[Neal]

It might also have to do with the fact that leopard tortoises here in the States are all mixed up. In Africa, the larger leopards grow in certain areas of Africa. When imported to the States, there is no longer the geographical barrier, and they are all interbred. So some of the larger tortoise genes are mixed in with the smaller tortoises.

This is the theory that I feel most likely explains what you are learning about as far as the differences in growth rates and size even among clutch mates. This article is a must read for anyone studying the taxonomy of leopard tortoises: http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Fritz_etal_2010a.pdf. Most all of the leopard tortoises here are of mixed localities, which is a combination of a lot of factors (mixing at the export locations in Africa, thoughtless breeding, importers and breeders not keeping records, etc...).

Another consideration that had not been previously mentioned is that there is some sexual dimorphism in some variants of leopard tortoises. Males grow larger or smaller than females. This would effect growth rates even among clutch mates.

Not directly related to the thread topic, but other sources of information in your studies: http://www.tortoiseforum.org/thread...-research-articles-and-case-study-list.58336/

 

[Kapidolo Farms]

The mixed genes wold only be a possible explanation for differing growth rates among the "regular" leopards. It would not explain why it happens among my sulcatas, Sudan sulcatas, 4 groups of russians (total of 20), pure South African leopards, and 10 stars.

Really one could argue that a regular leopard clutch with the same mother and father should all have the same growth rates, vs. a clutch that had multiple fathers.

Tom, unless they are literally clones, mixed genes count for much of the variability. Genotype and phenotype. Even maternal twins have differences in phenotype and behavior. Genes count for much given the constraint of environment. That you are removing the variable that is environemnt, it would follow that genes are more significant driver of these differences.