Why elephants rarely get cancer is a mystery that has stumped scientists for decades.  

If your partner has sex with someone else, it is considered infidelity - even if no emotions are involved. But it is also considered infidelity when your significant other develops a close personal relationship with someone else, even if there is no sex or physical intimacy involved.

A recent Norwegian study shows that men and women react differently to various types of infidelity. Whereas men are most jealous of sexual infidelity, so-called emotional infidelity is what makes women the most jealous. Evolutionary psychology may help explain why this may be.

Significant gender differences

If you've ever waited on an airport runway for your plane to be de-iced, had to remove all your food so the freezer could defrost, or arrived late to work because you had to scrape the sheet of ice off your car windshield, you know that ice can cause major headaches. 

In a new study, Nikola-Michael Prpic et al. have identified the driving force behind the evolution of a leg novelty first found in spiders: knees.  

With eight hairy legs and seven joints on each---that's a lot of joints for a spider to coordinate in order to take even a single step. To find some answers, Prpic's research team honed in on a gene called dachshund (dac). The gene was first discovered in fruit flies, and the discoverers named the missing leg segments and shortened legs that result from dac mutant flies after the short-legged dog breed of the same name. 

In pop culture, conspiracy believers like FBI agent Fox Mulder on The X Files or professor Robert Langdon in The Da Vinci Code tend to reject the notion of coincidence or chance; even the most random-seeming events are thought to result from some sort of intention or design. 

Psychologists have suggested that such a bias against randomness may explain real-world conspiracy beliefs but new research from psychologists at the University of Fribourg and the University of Paris-Saint-Denis shows no evidence for a link between conspiracist thinking and perceptions of order, design, or intent.