CyberDodo and greenhouse gases (1-40)
We have all heard about ‘greenhouse gases’, but do we know exactly what this phenomenon of...
Tortoises are amongst the oldest living animals on the earth, evolving only slightly over more than 100 million years.
This means that they were able to adapt to their environment, which was quite hospitable until the arrival onto the scene of ‘modern’ man and his serial destructive ways.
How many species of tortoise are there?
About 300 species, all ovipara, populate our planet, and are divided into 3 groups: aquatic turtles, marine turtles and land tortoises.
Aquatic turtles:
As their name suggests, they live in water or close to water. In this case, what is the difference between the group of aquatic and marine turtles? It all simply has to do with the issue of water; marine species live in salty water, contrary to their aquatic cousins, who need fresh water and who can even spend a part of their life on terra firma.
Amongst aquatic turtles, there are, for example, Florida turtles, unfortunately chosen as pets for many children, particularly in Europe where its importation has since been banned. Because as soon as they were let go (Forgetting that they were living beings and not toys), they were released into nature and in fact their voracity endangered (and still endangers, in some places) local biotopes.
Marine turtles:
A marine turtle is a reptile that is capable of making the deepest dive (more than 1,000 metres!), a turtle representative of this group could be the giant ‘Luth’, with certain species over a half tonne in weight and 2 metres in length. This exceptional creature has broken numerous records, including that of the heaviest turtle.
It is unfortunately under threat of extinction, of course always due to human activities (We will come back to this later).
Land Tortoises:
How can the giant tortoise of Seychelles not stand out as an example of the group of land tortoises? It measures more than a metre long, weighs 300 kilos, and particularly proves that it is sometimes profitable to take your time, because it has extraordinary longevity (Like its cousin from Galápagos). Scientists estimate that it is possible for them to live more than 150 years; a tortoise from Seychelles called Adwaitya even died in Calcutta zoo in 2006 and was more than 200 years old (But its exact age is steeped in controversy).
What threats are tortoises exposed to?
Even though there are several natural predators, both of sea turtles (Sharks, etc.) as well as land tortoises (Dogs, foxes, birds, snakes, etc.), and these are present at all times of their lives: when they are adults, when they are born or even when they are still in their shell, none of these dangers can compare to man.
A major danger for marine turtles is being accidentally caught during fishing; tens of thousands die this way every year. Another risk related to fishing is when turtles get caught by driftnets, and cannot get loose.
Plastic bags, which our modern civilisation has so much difficulty in doing without, are a perfect trap, because turtles believe that they are seeing jelly fish, try to swallow them and generally die as a result of intestinal complications, as well as a false feeling of being full.
A study published in 2009 by scientists N. Mrosovsky, Geraldine D. Ryan and Michael C. James with focus on the autopsy of more than 400 marine turtles shows that in more than one third of cases, the ingestion of plastic was the cause of death.
The threats to land tortoises are different, but just as serious, starting with the progressive disappearance of their habitat everywhere on the planet, due to the fact of human expansion.
Deforestation, fires, pollution, noise, roads, highways, the invasion of their living places by new predators, etc., in short, the destruction of their territories and biodiversity adds new species of tortoises each year onto the very worrying list of endangered species, which indeed does not stop growing.
Everyone in every country can contribute to the conservation of tortoises, for example: some can contribute by protecting the egg-laying sites, while others can simply refuse to buy animals which are trafficked illegally.
Everyone can contribute by preserving the environment and biodiversity!
To see the cartoon on Tortoises, click here
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