Arsip Kategori: Topik berbahasa Inggris

Starvation Didn’t Wipe Out Sabertooth Cats

starvation didn't wipe out sabertooth catsAround 12,000 years ago at the end of Pleistocene, some of Earth’s biggest mammals started going extinct–mammoths, mastodons, cave bears and dire wolves among them.

The cause of this mass die-out is still debated, though some researchers have pointed to dwindling food resources, possibly driven by warming temperatures and competition with humans, as a culprit. A new study suggests, however, that at least two of these long-gone creatures, sabertooth cats and their feline cousins, American lions, didn’t starve to death.

Big carnivores facing scarce resources often gnaw their prey to the bone and signs of this voracious eating behavior are evident in the wear and tear on their teeth. But the teeth of sabertooth cats and American lions from the La Brea Tar Pits in California have no such marks that would indicate a period of distress before extinction, the new analysis shows.

Adapted from: LiveScience

Bullying May Alter Gene Expression, Study Finds

Bullying may leave long-lasting scars on kids’ DNA in addition to their psyche, new research suggests.

A small study found that bullied kids are more likely to have changes in the expression of a gene involved in mood regulation compared with their identical twin siblings who were not bullied.

"Since they were identical twins living in the same conditions, changes in the chemical structure surrounding the gene cannot be explained by genetics or family environment," researcher Isabelle Ouellet-Morin said in a statement. "Our results suggest that victimization experiences are the source of these changes."

Adapted from: Live Science