Scientists have been investigating the specific emotions that separate a nightmare from a bad dream.
While most of us will remember waking up in the middle of the night after experiencing a particularly terrifying dream, researchers now believe that not all nightmares involve an element of fear. Instead, up to half of the unsettling dreams we experience may revolve around other emotions such as anger or sadness.
The team collected together more than 10,000 dream reports from 572 respondants and analyzed the emotional aspects of both nightmares (that wake the person up) and bad dreams (that generally do not cause the person to awaken.)
What they found was that nightmares tended to feature some form of physical threat such as being chased or falling from a great height, while bad dreams tended to revolve around some sort of psychological threat such as an interpersonal conflict or public embarrassment.
"Death, health concerns and threats are common themes in nightmares, but it would be wrong to think that they characterise all nightmares," said lead author Dr Geneviève Robert. "Sometimes, it is the feeling of a threat or an ominous atmosphere that causes the person to awaken. "
The remains of a prehistoric crocodile-like creature have been discovered in the wilds of west Texas.
It is thought that this particular specimen died in a lake over 205 million years ago, sinking to the bottom where its remains ended up being preserved thanks to the dirt and sediment. While only its head survived, palaeontologists were still able to identify it as a new species of phytosaur.
"A phytosaur resembles a crocodile," said Bill Mueller of the Museum of Texas Tech University. "They had basically the same lifestyle as the modern crocodile by living in and around the water, eating fish, and whatever animals came to the margins of the rivers and lakes."
The newly discovered species, which was named Machaeroprosopus lottorum after the family whose ranch the remains were found on, is believed to have grown up to at least 17ft in length.
Makenzie Wethington had been on a skydiving trip as a treat for her birthday when disaster struck.
The 16-year-old had jumped from the plane over Oklahoma when her parachute became tangled and failed to open properly. Instructors had attempted to offer her assistance over a headset, however she appeared to black out and subsequently plummeted more than 3,000ft to the ground.
As emergency crews rushed to the scene they were amazed to discover that despite some serious injuries, Makenzie was still very much alive. The impact had broken her pelvis, lumbar spine and shoulder blade but thanks to prompt medical intervention she was able to pull through. Doctors are optimistic that she will be able to leave the hospital's intensive care unit soon.
"I don't know the particulars of the accident, as I wasn't there," said trauma surgeon Dr Jeffrey Bender. "But if she truly fell 3,000ft, I have no idea how she survived."
