CLOSE
Original image
iStock

Why are Hammerheads' Heads Shaped Like That?

Original image
iStock

There are 10 species of sharks in the Sphyrnidae family, all of them but one falling into the genus Sphyrna, a Greek word that means “hammer”—an apt description for the head shape of these carcharhiniforms. But why are their heads, called cephalofoils, shaped like that? How does a hammer-shaped head, with eyes on each end, help the shark survive?

According to John S. Sparks, Curator-in-Charge of the Department of Ichthyology at the American Museum of Natural History and co-curator of its newest exhibition, Life at the Limits, there are two hypotheses scientists are working with. One, he says, is that “with its eyes out to the side, [the shark] can maximize its visual capacity, in terms of the area that it can see,” which might help when the animal is hunting.

The other has to do with how the hammerhead hunts: The sharks look for prey by rooting around on the ocean bottom with their heads, which are studded with sensory organs called ampullae of Lorenzini (the hammerhead isn't special, though; all sharks have these organs). “Every organism puts off a weak electric field, and [with these electroreceptors] the sharks can sense them,” Sparks says. “It’s thought that having a broader head allows for more of these ampullae, so the shark can be better sense prey.”

There may be some evidence to back up this hypothesis, Sparks says. Not all hammerheads’ cephalofoils are created equal: Some have small hammers, while some, like the great hammerhead, have huge hammers. The scientists behind one grant that Sparks reviewed "have found that sharks with larger hammers are more accurate at detecting prey in the substrate.”

Original image
iStock
arrow
Big Questions
Why Do Cats Freak Out After Pooping?
Original image
iStock

Cats often exhibit some very peculiar behavior, from getting into deadly combat situations with their own tail to pouncing on unsuspecting humans. Among their most curious habits: running from their litter box like a greyhound after moving their bowels. Are they running from their own fecal matter? Has waste elimination prompted a sense of euphoria?

Experts—if anyone is said to qualify as an expert in post-poop moods—aren’t exactly sure, but they’ve presented a number of entertaining theories. From a biological standpoint, some animal behaviorists suspect that a cat bolting after a deposit might stem from fears that a predator could track them based on the smell of their waste. But researchers are quick to note that they haven’t observed cats run from their BMs in the wild.

Biology also has a little bit to do with another theory, which postulates that cats used to getting their rear ends licked by their mother after defecating as kittens are showing off their independence by sprinting away, their butts having taken on self-cleaning properties in adulthood.

Not convinced? You might find another idea more plausible: Both humans and cats have a vagus nerve running from their brain stem. In both species, the nerve can be stimulated by defecation, leading to a pleasurable sensation and what some have labeled “poo-phoria,” or post-poop elation. In running, the cat may simply be working off excess energy brought on by stimulation of the nerve.

Less interesting is the notion that notoriously hygienic cats may simply want to shake off excess litter or fecal matter by running a 100-meter dash, or that a digestive problem has led to some discomfort they’re attempting to flee from. The fact is, so little research has been done in the field of pooping cat mania that there’s no universally accepted answer. Like so much of what makes cats tick, a definitive motivation will have to remain a mystery.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

Original image
RODRIGO ARANGUA/AFP/GettyImages
arrow
Animals
Listen to the Impossibly Adorable Sounds of a Baby Sloth
Original image
RODRIGO ARANGUA/AFP/GettyImages

Sometimes baby sloths seem almost too adorable to be real. But the little muppet-faced treasures don't just look cute—turns out they sound cute, too. We know what you're thinking: How could you have gone your whole life without knowing what these precious creatures sound like? Well, fear not: Just in time for International Sloth Day (today), we have some footage of how the tiny mammals express themselves—and it's a lot of squeaking. (Or maybe that's you squealing?)

The sloths featured in the heart-obliterating video below come from the Sloth Sanctuary of Costa Rica. The institution rescues orphaned sloths, rehabilitates them, and gets them ready to be released back into the wild.

[h/t The Kid Should See This]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios