<Ancient animal: Odontochelys / >Future animal- Caherbi Fostura


Gopher tortoise
Tortoises are reptiles and their history can be traced back to million years ago. Through evolution, they started to have radical changes and different species are formed. However due to spatial and ecological dimensions, some species extinct and some survived. This is called the Natural selection. The website provides information of one of the key stone species - Gopherus polyphemus commonly known as Gopher Tortoises. In addition, the links posted on the top of the page will lead you to know more about their ancestor and the future generation.

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Evolution of Testudinidae


Gopher Tortoises are herbivores and do not have any distinct features that allow them to stand out from the crowd. Instead, they are either tanned or brown. An average gopher tortoise can be 29 pounds heavy and 9 to 11 inches long. Although their features are common,they play an important role for other animals. Unlike others, these tortoises dig burrows as homes. It is because of their burrows, thousands of animals are saved from natural disasters such as bush fires, therefore they can be called 'the keystone species'. No different from any other tortoises, they can live up to 60 years old. Sadly, due to diseases and human impacts they are listed as vulnerable species in the conservation status.

Scientific classification :

Level
Classification
Kingdom

Animalia
Phylum
Chordata
Class
Reptilia
Order
Testudines
Suborder
Cryptodira
Superfamily
Testudinoidea
Family
Testudinidae
Genus
Gopherus



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Gopher Tortoise's Skeleton


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Side View Analysis of the Gopher Tortoise



















- The domed shell protects the tortoises' back flesh and acts as a temporary shelter if predators attack

- Its sharp saw blade helps to rip off plantations

- Gopher Tortoises are most likely not to get hurt because of their hard scale skin

- Flat front legs are for digging burrows.

- Sharp claws help to dig deeper and faster.



Habitat is place that provides safety, food and water supply which also suits a particular animal. Just like any other species in the world, the Gopher Tortoise has its own unique habitat. Living near the Llama, vultures, walking albatross in the south of america, the gopher tortoises are situated in South-eastern America- Florida, Georgia, Alabama, Mississippi, south-eastern Louisiana and South Carolina.


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Map of America with highlighted states


Although there are variations in the Southeastern America’s climate, it is usually hot and humid in the long summers and has short mild winters. Plants like longleaf pine, turkey old sandhills, pine flatwood and savanna, coastal dune, barrier island and oak scrubs grow around the regions. The reason to why the gopher tortoises only live in these regions is because of the general climate and plantations that satisfy their needs. With the hot and humid climate accompanied by sandy landscapes and great range of food, Gopher Tortoises classify home in highlighted areas.

However the population started to decrease when there was an interference with human activity. When the humans decide to build more housings, expand the logging industry, it brings fatal consequences to the tortoises because the environment around their burrows are spoil. Fortunately, there are organisations such as Gopher Tortoise Organisation and Gopher Tortoise Council Organisation to help protect and sustain their populations through educational programs.



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Environment around Gopher Tortoise's Burrow
With the suitable environment, (the image above would be the perfect ) these tortoises will start to breed. Unlike other animals, they breed in spring when the males let out short calls to attract opposite sex. It is common to see males and females wrestling with each other before mating for it are part of the courtship. The eggs will be laid between mid May and June in burrows that receive a lot of sunlight. The hatching's sex will be determined by the temperature around them. If they are incubated over 30 ºC they are female, if less then 30 ºC they are male.Sadly, predators like raccoons, skunks, armadillos, foxes and opossums can easily dig them up.




With evolution comes the need to adapt, through out million years animals’ adaptations change to cope with their habitat. However, adaptations can be branched out to 3 different types. Structural adaptation is physical features of an organism. Behaviour adaptation is the ability to learn or perform a serious of actions around certain environment. Physiological adaptation allows animal to perform functions.

Structural adaptations:

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Comparision of the burrow's width to the tortoise's shell
1)Gopher tortoises have strong hind legs similar to a shovel. The environmental pressure that could have led them to change is the need to dig long burrows. Just by moving forwards and backwards with its shovel like legs, the sand will be easily extracted and after several days of continue digging, a 30 ft burrow will be dug. Sometimes depending on the water table of the burrows, the length can vary.

<<This image shows the tortoise crawling back to its ‘home’. The burrow entrance might look small and shallow, but its width is the same as a tortoise’s shell allowing it to move freely.






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How the shell protects tortoises from predators
2) Furthermore, they along with others have shells to protect themselves.
Different from pancake tortoises that have flat, soft shells allowing them to run faster and slip into stone cracks, the gopher tortoises have big domed shells. Due to the soft, venerable back flesh that can be easily attacked by eagles and other predators, the shells protect them from harm effectively. Although these shells are heavy and might seem to be a burden because they cant run faster, yet they act as a temporary shelter. Once the predators like eagles attempt to attack them, the tortoise can immediately retract its limbs and head into the hard shell, avoiding the pecking on soft flesh. Also, because of the deep, dull colour it can help them absorb the sun's heat and regulate the blood. Furthermore, it acts as a camoflage near its habitat.









The evolution of tortoise shell:



Behavioural adaptations:

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Gopher Tortoise Sunbathing
1) These gopher tortoises like to dig burrows in areas where it receives a lot of sunshine. As cold blooded animals, tortoises need to live in areas where they can easily crawl out from the burrows and receive heat to warm up their blood. The reason they dig burrows is because the gopher tortoises can not sunbath the whole day. If they do, they will die from the hot temperature. Therefore, they dig burrows as deep as 30 ft to protect themselves from the harsh sun. Furthermore, these burrows can protect tortoises from natural disasters such as drought, bushfire. Due to the fact that the deeper the burrow is the cooler the temperature will be, the tortoises wont be affected by the hot weather. In addition, these burrows that are dug out by the tortoises are all located in soils that drain well and where water table is low enough, therefore if the flood wont affect them.







gophers-courting.jpg2)The breeding season starts between April and May. This is the time where males become aggressive with each other, and attract females’ attention by giving out short calls. If one is ignored, the males will walk to the female’s burrow entrance and will start to bob its head for a while. After a few minutes, the males retreats and if successful the female will come out as a sign of ready. Before the mating begins, there tend to be a little fight between the couples. The male will bite the female’s foreleg as a signal to turn around ; once she gets the signal the mating begins. This happens because tortoises hearing arent that good, by biting on the for leg, it helps them understand what to do next.







Physiological adaptation:
Although living in hot areas such as Florida, Georgia etc, gopher tortoises have a need to hibernate during winter. Hibernation happens when gopher tortoises metabolism runs low . By hibernating, they can avoid the harsh, cold weather and the need to find food (plantations that die during winter). Therefore it allows them to rest for a long period without consuming any food or water. Yet before hibernation, the tortoises have to eat enough plantations to store as fat and reuse it as energy while hibernating. The first signs of tortoises wanting to hibernate are slowing down in speed and reduction in appetite.




References/ Bibliography