October to March is turtle time at Wilderness Safaris, with Rocktail offering guests front row seats to one of the world’s most fascinating spectacles – the laying and hatching of leatherback and loggerhead turtles…
Join Ezemvelo KZN Wildlife and Rocktail on a turtle drive to witness the female turtles coming ashore to dig their nests and lay their eggs. Then, return a few months later to watch the hatchlings make their way to the ocean.
A big head…
Loggerheads are named for their relatively large heads, which support a very powerful jaw. Using their powerful jaws they crack open crustaceans such as crabs and even seemingly impenetrable molluscs such as the queen conch and giant clams.
The largest and oldest…
The leatherback turtle is the largest of the sea turtles and also one of the largest reptiles in the world. Its size ranges from 1.2 to 2.4 metres and can weigh between 225 and 900 kg. An average adult measures between 1.5 to 1.8 metres and can weigh between 270 to 360 kg. Not only are leatherback turtles the largest but also the oldest of the sea turtles, having being around for more than 150 million years. They survived the extinction of the dinosaur!
The most common…
The marsh terrapin (often mistaken as a turtle) is the most widespread terrapin species in Africa. This hunter-scavenger hunts in packs and will eat almost anything from young birds to small mammals and even parasites lodged in the skin of a rhino enjoying a mud bath. But the march terrapin's reputation is not just odious, but odorous as well. It smells really, really awful. That aroma comes from four glands, one under each leg, which release a foul-smelling liquid. Despite that unpleasant odour, villagers sometimes dig up the terrapin from their mud nests during the wet season for food.
Can a turtle be scared out if its shell…
Contrary to what we see in animated cartoons, turtles can’t remove their shells or crawl out of them. It would be like a human dismantling their own spine and ribs. The shell is made up of about 50 different bones and is actually an evolutionary modification of the rib cage and part of the vertebral column. The shell consists of an upper section, the carapace and a lower portion called the pastron joined by a bony bridge. Some turtles have a moveable joint, usually in the plastron, that acts as a hinge and enables the creature to pull the shell sections together tightly while it retracts its body inside. The shells have nerves embedded in them and a blood supply. If a turtle’s shell is injured, it may bleed and feel pain.
An eerie noise…
Turtles can make sounds by swallowing or by forcing air out of their lungs producing some unique noises. The giant musk turtle from Central America is known for yelping like a dog when it is startled or being attacked. Nesting female leatherback turtles probably make the weirdest sound of them all – a distinctly unladylike noise that resembles a human belching.
Can turtles hear?
Turtles lack an ear opening, but that does not mean they are deaf. It is true that they are not able to hear anywhere as well as humans, but they can detect certain types of sounds. Scientists have found that turtles’ middle-ears have a very thick eardrum-like membrane which limits the frequency range they can receive.
That turtle needs CPR!
It is easy to tell when most animals breathe as they draw air in and out their lungs using the diaphragm, a muscle that contracts and relaxes with each breath to expand the ribs. But turtles do not have a diaphragm. A diaphragm would not have helped either, since the rigidity of their shells would prevent their ribs from expanding. Instead, turtles move their limbs or neck and utilize other muscles connected to their pleural cavity (the area around their lungs), to help them breathe. Some turtles also have special muscles situated between their limbs and lungs to aid in breathing; others have an additional breathing-related trick that allows them to remain underwater for longer periods. Some turtles use buccopharyngeal breathing, in which they take water into their mouths and then pass it out of their nostrils. Along the way, the oxygenated water passes along the capillary-rich tissue inside their necks, allowing additional oxygen to enter directly into the bloodstream.
Most female turtles will return to the same beach each time to nest and will often appear a few hundred meters from where they last nested. The nesting mostly happens at night when the female crawls out of the ocean, pausing frequently as if carefully scoping out her spot. She may decide not to nest and it can happen naturally or because of artificial lighting or the presence of people on the beach. On average they can nest at least twice during the nesting season. A female turtle crawls to a dry area where she will construct a pit by digging with her flippers. She will lay between 80 to 120 eggs. The eggs are very flexible and do not break as they fall into the pit. She will close the pit and gradually pack the sand down over the top of the eggs. By throwing sand in all directions she tries to make it harder for predators to find the eggs.
Emerging from the Nest
Unlike crocodiles, sea turtle hatchlings do not get support from their mothers when they hatch. To break open their shells, they use a sharp tooth to break the shell. Digging out of the nest is a group effort that can take several days with the hatchlings emerging at night or during a rainstorm when temperatures are cooler. They then dash towards the sea using the brightest horizon as their navigation.
Survival of the fittest…
A young turtle hatchling has a 1/1000th chance of surviving to adulthood. From the moment that they hatch it is a fight for survival. If they do not make it to the ocean quickly enough, they will die of dehydration in the sun or get caught by predators like birds and crabs. When they finally make it to the open ocean they are hunted by sharks, big fish and circling birds.
As usual, humans also play a big role in the changes of survival and include:
- habitat loss and degradation
- wildlife trade
- collection of eggs and meat for consumption
- incidental capture
- climate change
In many countries of the world people help protect the feeding and nesting grounds of sea turtles by monitoring their movements and protecting their eggs from being harvested by local communities. It is important that countries and people from different cultures cooperate and share responsibility. If sea turtles cannot survive and reproduce on their own, without help from humans, then they are doomed.