#conservationstatus-vulnerable

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The Diamondback Terrapin, or Malaclemys terrapin terrapin, is a small turtle species from the swamps of the Eastern and Southern USA. Due to overhunting for their meat in the early 1900s they've been close to the brink of extinction. Since, in more modern times, increased urban development in the areas where they live and lay their eggs have also negatively effected their numbers. With protective legislation in place in many of the states they inhabit, their population has managed to recover somewhat, getting classed as a Vulnerable species. A current risk for terrapins is posed by commercial crab traps in which they often get caught and drown.

Due to living in the area where saltwater and freshwater converge, terrapins, similar to sea-dwelling turtles, have salt glands which allow them to get rid of any excess salt that they've accumulated from living in semi-saltwater environments. In order to avoid dehydration they need to visit freshwater on a regular basis.

Fun fact: the concentric rings within the plates of Diamondback terrapins' shells are growth rings that form as the terrapins get larger (similar to how a tree adds growth rings the older and wider they get).

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The Aldabra Giant Tortoise, or Aldabrachelys gigantea, only lives on the Seychelle Islands in the Indian Ocean and is known for their size with males averaging between 200-250 kilos, and females between 121-159 kilos.

They are classed as a Vulnerable species due to historic hunting practices wiping out the majority of giant tortoise species. In fact: the Aldabra Giant Tortoise is the only one of 18 giant tortoise species that has not gone extinct. The reason for the overexploitation (mainly in the 17th and 18th centuries) was that the tortoises provided an excellent source of oil and meat that could very easily be caught and could even more easily be kept on board ships (a giant tortoise can relatively easy go without food or water for an entire year!). Captive breeding programs have been able to somewhat bring the species back from the brink of dying out by releasing the captive bred tortoises back into the wild where they are now protected by conservation efforts.

What makes this effort somewhat easier is that the numbers of eggs in a clutch in captive circumstances are between 9-25 (in the wild those numbers sit between 4-14). Although in both cases only 30-50% of the eggs per clutch actually hatch, this still means that more tortoises can be released in the Seychelles.

While they have one of the longest lifespans of any animal on earth (oldest record is 255), Aldabra Giant Tortoises only reach a breeding age somewhere between 20-30 years old, making a breeding program a very slow-going and time-consuming effort. Another factor in the result of the numbers of successful hatchings is that the sex of a hatchling depends on the incubation temperature of the nest: warm eggs produce more females, cool temperatures more males. A third impact on hatchling-numbers (only happening to nests in the wild) is that eggs and juveniles are easy pickings for crabs looking for a tasty snack.

Fun fact: Aldabra Giant Tortoises are so large that they carve paths through their environments which are often used by other foraging animals and by doing this the tortoises provide a very important ecosystem service.