Immaculate conception…in sharks?
After a mass artificial insemination project in sharks, researchers found that some white-spotted bamboo sharks had “virgin births”, where their babies had no fathers at all.
The team artificially inseminated 20 female sharks to help boost population numbers, as they detail in their paper, published in Scientific Reports. Despite some sperm coming from far off aquariums, it was still able to successfully inseminate females. Most interestingly, two sharks just gave up on men altogether and reproduced on their own – a feat called parthenogenesis.
“One of the goals of this pilot project was to just see if it worked,” says Kevin Feldheim, co-author from Chicago’s Field Museum. “Now, we can extend it to other animals that actually need help breeding, from other species in aquariums to sharks under threat in the wild.
“We wouldn’t know about parthenogenesis in sharks if it wasn’t for aquariums.”
No need to lose your head over a lost noggin, because a shrunken head has been authenticated and returned to Ecuador.
The tsantsa, as it is known, was found in storage at Mercer University, US, and its authentication involved CT scans and rigorous assessment of 33 criteria to identify where the head originally came from, the team show in their paper, published in Heritage Science.
Notable identifiers were the size of the head – comparable to an adult human fist – and three holes in the upper and lower lips that were joined with plant fibres; both of these were common in ceremonial use of the heads in Ecuadorian Amazon.
Elephant seal deep dive
Hungry elephant seals spend 80% of their day fishing and foraging, and they feed up to 2000 times a day, according to a new paper, published in Science Advances. They get their frequent snacks by diving down to the mesopelagic zone, which is 200–1000 metres below the surface.
As that area of the ocean becomes more and more affected by climate change, the elephant seals may have trouble foraging for small fish. Regardless, the amount of fishing they do could be a good indicator of mesopelagic health.
Grab your kale, because eating fruit and veg is linked to lower stress, according to a new study published in Clinical Nutrition.
The team, led by Simone Radavelli-Bagatini from Edith Cowan University in Western Australia, found that people who eat at least 470 grams of fruit or veg each day reported 10% lower stress levels than those who ate less than 230 grams, regardless of age.
“Vegetables and fruits contain important nutrients such as vitamins, minerals, flavonoids and carotenoids that can reduce inflammation and oxidative stress, and therefore improve mental wellbeing,” says Radavelli-Bagatini.
“Previous studies have shown the link between fruit and vegetable consumption and stress in younger adults, but this is the first time we’re seeing similar results across adults of all ages.
“The study’s findings emphasise that it’s important for people to have a diet rich in fruit and vegetables to potentially minimise stress.”
Lizard bubble head charm
A team from the University of Toronto in Canada has found that semiaquatic Anolis lizards are able to breathe underwater due to little bubbles that cling to their snout.
“We found that semi-aquatic anoles exhale air into a bubble that clings to their skin,” says lead author Chris Boccia.
“The lizards then re-inhale the air – a manoeuvre we’ve termed ‘rebreathing’ after the scuba-diving technology.”
The rebreathing technique extended the time the lizards could spend underwater, which is up to 18 minutes. The authors also suggest the bubbles may even collect oxygen from the water itself.
“It’s too early to tell if lizard rebreathing will lead to any particular human innovations,” says Boccia. “But biomimicry of rebreathing may be an interesting proposition for several fields – including scuba-diving rebreathing technology, which motivated our naming of this phenomenon.” The paper was published in Current Biology.
Deborah Devis is a science journalist at Cosmos. She has a Bachelor of Liberal Arts and Science (Honours) in biology and philosophy from the University of Sydney, and a PhD in plant molecular genetics from the University of Adelaide.
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