Turtles are truly prehistoric animals, they have been on earth for more than 200 million years and have survived severe climatic changes such as those that led to the extinction of the dinosaurs. Turtles live all over the world in almost every type of climate
They spend most of their lives in water. They are adapted for aquatic life, with webbed feet or flippers and a streamlined body. Sea turtles rarely leave the ocean, except to lay eggs in the sand. Freshwater turtles live in ponds and lakes, and they climb out of the water onto logs or rocks to bask in the warm sun.
A turtle's shell is a modified ribcage and part of its vertebral column. The top part of the shell is called the carapace, and the bottom is called the plastron. The shell is made up of about 60 bones that are covered by plates called scutes. Scutes are made of keratin, the same material that makes up humans' fingernails. All turtles, except sea turtles, are able to retract their heads and feet into their shells to protect themselves from predators.
Most turtle species lay their eggs in a perceived safe place, bury them in the sand for protection and as far as we are aware play no further role in the raising of the young. But recent research has demonstrated that at least one species, the giant South American river turtle, also known as the Arrau Turtle, does take parental care of their offspring, communicating with its hatchlings whilst they are still in the egg, after they hatch and in when they reach the water.
The giant South American river turtle is the largest freshwater turtle in South America. It is one of the most social species of turtles, individuals migrate together, they nest communally, and they hatch in largs numbers together.
The very idea that turtles can communicate with each other using sound is rather new. Turtles lack vocal cords and their ears are internal, so for many years researchers simply assumed turtles had little to no ability to hear. This knowledge has changed in recent years as we have learnt that some species of tortoise make ‘barking’ noises, others may sound like whirring motors, for example, and some even make belching noises. The Red-Footed Tortoise, which lives in South America, makes clucking sounds a bit like a chicken whilst the Egyptian tortoise sings when it is mating.
One of the reasons it’s taken us so long to learn about these sounds is that turtles communicate at frequencies in the lower range of the human audible spectrum. Like whales, turtles probably use these frequencies because the sounds can travel long distances underwater.
The giant South American river turtles uses clicks and clucks to call to their hatchlings whilst they are still inside the egg, this is thought to the help stimulate the group to emerge all at once.
But unlike other turtle species that hatch en masse, giant South American river turtles receive the parental care of their mothers as soon as they reach the water. The mums wait in the area were they have laid their eggs for up to two months, and once ready they start calling out to the babies. Once the two generations meet up, they migrate together from the beach back to the river’s flooded forests.
As of yet this is as far as our knowledge extends with regards to the extent of their relationship, but it is likely that with an ability to recognise each other individually, relationships between mother and offspring may well continue as the young grow.
Turtles really are amazing animals
VIDEO: Click here to ‘Take a ride on the back of a giant river turtle’ and see a hatchling interact with it’s mother
Sadly, many species of turtle are endangered! 129 of approximately 300 species of turtle and tortoise on Earth today are either vulnerable, endangered, or critically endangered, according to the IUCN. Threats include loss of habitat, poaching and the illegal pet trade
Threats to turtles
Now that we know giant South American river turtles rely on communication to enable hatching and migration, we need to determine what effect shipping noise might have on the animals. There’s already plenty of evidence that the noise created by oil and gas exploration is detrimental to a wide variety of marine mammals, so perhaps turtles are also at risk.
Unfortunately, this species is also under threat from the illegal wildlife trade and local appetites. Brazilians prize turtle eggs as a delicacy, and the turtles themselves are often slaughtered for meat. A recent trend toward dam building in the Brazil also presents severe threats to their habitat.
While the International Union for Conservation of Nature currently lists the giants as being of “Least Concern,” the Tortoise and Freshwater Specialist Group has strongly recommended a change in status to “Endangered.”
Local community protection of the giant South American river turtle
Following a decline in the number of he giant South American river turtles due to egg collecting and meat, a group of community members living in the Brazilian Amazon created biodiversity hotspots along a section of the Juruá River, safeguard beaches from the illegal activity. And egg harvesting has plummeted on beaches under their watch.
During the five- to six-month long summer dry season, locals watch over the sands of 14 beaches from a wooden hut 24 hours a day, 7 days a week. In exchange for their constant vigilance, they receive a monthly stipend of food items worth about $110 U.S. dollars from a partnership between government agencies and universities. Their efforts have radically altered the protected beaches.
Thanks to the community member guards, the number of South American river turtle nests on protected beaches has skyrocketed. Eleven times more nests inhabit the beaches than 40 years ago. The number of hatchlings born on the guarded sands has likewise multiplied. Compared to unprotected beaches in the area, a staggering 58 times more nests occupy protected beaches
The conservation efforts extended beyond the giant South American river turtle. Green iguana nests became seven times more abundant on the protected beaches compared to unprotected ones in the region. Migratory bird nests boomed with protected beaches hosting 8,700 nests compared to less than 400 on unprotected shores. The conservation efforts strengthened insect and fish populations, too.
Even in protected conservation areas, the watchful eye of locals made a difference. Poachers harvested 99 percent of nests not under surveillance in conservation areas. In contrast, egg robbing plunged to just about 2 percent on guarded beaches, meaning the biodiversity boom was thanks to the dedicated labor of locals more than the protected status of the land.
Click here for more details of the community protection