Turtles are extraordinary creatures that have inhabited the Earth for more than 200 million years, surviving the extinction of the dinosaurs and witnessing monumental transformations on the planet. Their longevity, adaptability and peculiar appearance have made them the protagonists of numerous legends, myths and scientific studies.
1. An Ancestral Lineage
Turtles are one of the oldest species still in existence on Earth. They are thought to have first appeared during the Triassic period, over 220 million years ago, making them contemporary with the dinosaurs. Throughout their evolution, they have maintained many of their original features, such as their famous shell. This shell is not only a defence against predators, but is also one of the most ingenious evolutionary adaptations in the animal kingdom.
A turtle's shell is made up of over 50 different bones that have been fused together over time, including its spine and ribs. This makes its shell an integral part of its bone structure, not a separate piece of armor as many believe.
2. The World's Longest-Living Turtle
One of the most remarkable curiosities about turtles is their longevity. Many species of turtles can easily live for over 100 years, with some even exceeding 150 years. One famous example is Jonathan, a giant tortoise from the Seychelles who currently holds the title of the world's longest-living land tortoise. Born in 1832, Jonathan is over 190 years old and is still active on the island of Saint Helena.
The secret of turtles' longevity still puzzles scientists, but their slow metabolism and quiet lifestyle are thought to be important factors. In addition, some turtle species are extremely resistant to diseases that affect other animals.
3. Species Diversity
There are more than 350 species of turtles, distributed in different habitats around the world. They can be found in both marine and terrestrial environments, from the warm waters of the Pacific to arid deserts. Among the best-known species are the green turtle, the leatherback turtle and the giant tortoises of the Galapagos Islands.
Each of these species has unique adaptations that allow them to survive in their environment. For example, sea turtles have flippers instead of legs, allowing them to swim with great efficiency, while land turtles have strong, robust limbs for digging and walking long distances.
4. Expert Navigators
One of the most amazing abilities of sea turtles is their ability to navigate long distances across the ocean. Some species, such as the loggerhead turtle, can travel thousands of miles between their feeding and nesting grounds. Turtles are thought to use a combination of magnetic signals from the Earth, ocean currents, and chemical factors to orient themselves in the vast ocean.
These navigational skills are astonishing considering that many sea turtles travel alone, without the help of a group or guide. Young sea turtles, after hatching on the beaches where they were born, embark on epic journeys into the open ocean, only to return years later to the same spot to lay their own eggs.
5. Sex Determined by Temperature
Another fascinating fact about turtles is that the sex of the offspring is not determined by genes, as in most animals, but by the temperature at which the eggs are incubated. In many turtle species, warmer temperatures tend to produce more females, while cooler temperatures favor the birth of males.
This phenomenon, known as "temperature-dependent sex determination," has raised concerns among conservationists that global warming could disrupt the gender balance in turtle populations, with a disproportionate increase in females in certain regions.
6. An Amazing Breath
Although most turtles breathe through their lungs, some species have developed alternative mechanisms to obtain oxygen in extreme conditions. Sea turtles, for example, can hold their breath for several hours underwater thanks to their ability to reduce their heart rate and, consequently, their need for oxygen.
However, one of the most curious adaptations is found in freshwater turtles, which can absorb oxygen through the skin around their cloaca, an opening located at the back of the body. This adaptation allows them to remain underwater for long periods without needing to come to the surface to breathe.
7. The Riddle of the Shell
The shell of turtles, as we mentioned above, is one of the most distinctive structures of these reptiles. It is composed of two parts: the upper shell or "back" and the lower shell or "plastron". But how has this structure influenced the evolution of turtles?
It has been discovered that the shell not only provides them with protection from predators, but also allows them to survive in harsh environments, such as deserts. Some turtles, such as the desert tortoise, have the ability to store water in their body during long periods of drought. In addition, the shell acts as a temperature regulator, helping to keep their body cool or warm as needed.
8. Communication and Socialization
Contrary to what many might think, turtles are not completely solitary creatures. Although many species live in isolation, there are times when turtles interact with each other, especially during mating season. Some marine species, for example, use underwater vocalizations to communicate, although these sounds are almost inaudible to the human ear.
Tortoises can also display social behaviors. During mating season, males often engage in courtship rituals that may include jostling, head-butting, and even "dancing" around the female.
9. The Myth of Slowness
Turtles have gained a reputation for their slowness, and while this is true for many land-based species, it does not apply to sea turtles. In fact, some marine species, such as the leatherback turtle, can swim at speeds of up to 35 km/h. These turtles, with their streamlined bodies and powerful flippers, are perfectly adapted to move with agility in the water.
Land tortoises, though slower, are also capable of moving at a respectable pace when necessary. However, their body design, with shorter, more robust limbs, is more adapted to endurance than speed.
10. Threats and Conservation
Despite their resilience and adaptability, many turtle species are currently in danger of extinction due to human action. Ocean pollution, poaching, habitat destruction and climate change are some of the main threats facing these reptiles.
One of the biggest threats to sea turtles is plastic pollution. Every year, thousands of turtles get caught in fishing nets or ingest plastic bags that they mistake for jellyfish, their main source of food. In the case of land turtles, habitat loss due to human expansion and agriculture has also caused a drastic decline in their populations.
Fortunately, conservation efforts in many parts of the world are helping to protect turtles. In places like the Galapagos Islands and the beaches of Costa Rica, conservation initiatives are focused on protecting nesting sites and reducing poaching.
The future of turtles depends largely on our efforts to protect their habitat and ensure their survival. By learning more about these creatures and the threats they face, we can take steps to ensure they continue to swim and walk our planet for many centuries to come.