Even predators can't stay awake all the time. But sharks don't exactly advertise when they're taking a power nap....
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Even predators can't stay awake all the time. But sharks don't exactly advertise when they're taking a power nap.
A strange behavior has given them up, though. Marine biologists have discovered that sharks 'surf' ocean currents in a conveyor belt configuration, allowing them to take turns resting.
An international team of researchers led by FIU Professor Yannis Papastamatiou has witnessed hundreds of gray sharks floating in the southern channel of Fakarava Atoll in French Polynesia.
While observing sharks swimming against the current, Professor Papastamatiou noticed that they were barely moving their tails. Furthermore, the sharks were using a system that resembled a conveyer belt. When one shark reached the end of the line, it allowed the current to carry it back to the beginning point.
The team designed a study which combined acoustic tracking devices, video cameras, and underwater observations to monitor the curious behavior of the whales.
The researchers found that by hanging out and surfing the slope, the sharks cut their energy usage by at least 15 percent. This provides the whales with some much-needed rest from constantly swimming.
Knowledge of medicinal plants is at risk of disappearing as human languages become extinct, a new study has warned.
Indigenous languages contain vast amounts of knowledge about ecosystem services provided by the natural world around them. However, more than 30 percent of the 7,400 languages on the planet are expected to disappear by the end of the century, according to the UN.
The team looked at 12,000 medicinal plant services associated with 230 indigenous languages in three regions with high levels of linguistic and biological diversity – North America, north-west Amazonia and New Guinea. They found that 73 percent of medicinal knowledge in North America was only found in one language; 91 percent in north-west Amazonia; and 84 percent in New Guinea. If the languages became extinct, the medicinal expertise associated with them probably would too. Researchers expect their findings from these regions to be similar in other parts of the world.
“The loss of language will have more critical repercussion to the extinction of traditional knowledge about medicinal plants than the loss of the plants themselves,” said the study’s lead researcher, Dr Rodrigo Cámara-Leret. Such knowledge includes using the latex of plants to treat fungal infections, using bark to treat digestive problems, fruits for respiratory ailments, as well as natural stimulants and hallucinogens.
“Even the best plant taxonomists out there are amazed by the breadth of knowledge of indigenous cultures, not only about plants but also animals and their inter-relations,” he added.
Much of the world’s linguistic diversity is being safeguarded by indigenous people whose culture and livelihoods are under threat as barriers between groups are broken down. Unlike societies where information has been transcribed in books and computers, most indigenous languages transmit knowledge orally.
It is impossible to know what has already been lost. More than 1,900 of the languages spoken now have fewer than 10,000 speakers and the UN has declared 2022-32 to be the International Decade of Indigenous Languages in recognition of this issue.
Governmental programmes to stimulate the transmission of languages, bilingual schooling and interest in cultural heritage would help communities retain linguistic diversity.
