Understanding the evolution of nocturnal mammals by studying their extinct relatives

Humans are diurnal. We sleep at night and are active during the day. (That isn’t to say that I feel particularly diurnal most mornings, given that my alarm has to make it through a few snooze cycles to wake me up and coffee is the only thing keeping me from napping under my desk at work.) Most mammals, though, don’t share our ostensible predilection for daylight; only 20% of mammal species are diurnal like us. Of our mammalian relatives, nearly 70% are nocturnal. The rest are crepuscular (active at dawn and dusk) or cathemeral (active during both day and night).

A tarsier (Flickr: )

A tarsier from Borneo. (Flickr: Erwin Bolwidt)

Mammalogists like myself often think nocturnality is a particularly mammalian thing because—let’s be honest here—nearly all of the coolest nocturnal vertebrates are mammals. How can you compete with the likes of tarsiers, vampire bats, leopards, and—strangest of them all—the aye-aye? I’ll throw the ornithologists a bone and acknowledge the enduring awesomeness of owls, but they are the odd birds out in a group that’s mostly diurnal.

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Fossil hunting with the Brain Scoop

We’re big fans of Emily Graslie’s natural history video series The Brain Scoop. The latest episode goes right to the source of the museum specimens that usually take center stage—a fossil hunting expedition.

Watch the whole thing, and you’ll learn some nifty paleontology jargon, like:

“It’s called the 18-inch layer.”

“Is it because it’s 18 inches?”

“Yeah.”

Friday coffee break

2010.03.24 - Ramona likes her coffee

Every Friday at Nothing in Biology Makes Sense! our contributors pass around links to new scientific results, or science-y news, or videos of adorable wildlife, that they’re most likely to bring up while waiting in line for a latte.

From Sarah: Paleontologists have recreated how Tyrannosaurus rex probably went about eating a Triceratops.

As [Museum of the Rockies paleontologist Denver] Fowler and his colleagues examined the various types of bite mark on the skulls, they were intrigued by the extensive puncture and pull marks on the neck frills on some of the specimens. At first, this seemed to make no sense. “The frill would have been mostly bone and keratin,” says Fowler. “Not much to eat there.” The pulling action and the presence of deep parallel grooves led the team to realise that these marks were probably not indicative of actual eating, but repositioning of the prey. The scientists suggest that the frills were in the way of Tyrannosaurus as it was trying to get at the nutrient-rich neck muscles.

From CJ: Fourteen-year-old teaches his dad about Dungeons and Dragons, lands first-author spot on resulting journal article.

Alan Kingstone, a psychologist at the University of British Columbia, had a problem: all humans have their eyes in the middle of their faces, and there’s nothing that Kingstone could do about it. His 12-year-old son, Julian Levy, had the solution: monsters. While some monsters are basically humanoid in shape, others have eyes on their hands, tails, tentacles and other unnatural body parts. Perfect. Kingstone would use monsters. And Julian would get his first publication in a journal from the Royal Society, one of the world’s most august scientific institutions.

From Noah: To save natural areas, do we have to put a price tag on them?

But the rising tide of enthusiasm for PES (or payment for ecosystem services) is now also eliciting alarm and criticism. The rhetoric is at times heated, particularly in Britain, where a government plan to sell off national forests had to be abandoned in the face of fierce public opposition. (The government’s own expert panel also found that it had “greatly undervalued” what it was proposing to sell.) Writing recently in The Guardian, columnist and land rights activist George Monbiot denounced PES schemes as “another transfer of power to corporations and the very rich.”

From Devin, here’s video of the rhinoceros beetles studied by Doug Emlen’s lab, which recently landed a paper in Science for explaining why those horns make a good indicator for choosing a mate.

Friday coffee break

Musical coffee

Every Friday at Nothing in Biology Makes Sense! our contributors pass around links to new scientific results, or science-y news, or videos of adorable wildlife, that they’re most likely to bring up while waiting in line for a latte.

From Noah: Paleontologists reconstruct the song of a fossilized Jurassic-era katydid.

Examining the insect’s seven centimeter long fossil wings under microscope, researchers were able to see how the prehistoric male katydid employed stridulation, i.e. rubbing body parts together, to produce a song to attract a female.

From Jon: A tranquilizer that is commonly abused as a club drug shows great promise for treating depression.

And the patient, they say, you know, yeah, it helped with my pain, but, you know, my depression seemed better. And so this was sort of a curiosity for a long time until a few years ago, when some folks at the National Institutes of Health decided that they really wanted to check this out.

From Sarah: The New York Times on the natural history of venomous mammals.

Every so often, however, a mammalian lineage discovers the wonders of chemistry, of nature’s burbling beakers and tubes. And somewhere in the distance a mad cackle sounds.

Skunks and zorilles mimic the sulfurous, anoxic stink of a swamp. The male duck-billed platypus infuses its heel spurs with a cobralike poison. The hedgehog declares: Don’t quite get the point of my spines? Allow me to sharpen their sting with a daub of venom I just chewed off the back of a Bufo toad.

From Jeremy: Antibiotic-resistant strains are now so widespread that we may soon see the day when gonorrhea is untreatable.

Gonorrhea is one of the most common sexually transmitted diseases in the world—with about 600,000 cases diagnosed in the U.S. each year. A few years ago, investigators started seeing cases of infection that did not easily respond to treatment with a group of drugs called cephalosporins, which are currently the last line of defense against this particular infection. Now, the number of drug-resistant cases has grown so much in the U.S. and elsewhere that gonorrheal infection may soon become untreatable, according to doctors writing in the February 9 issue of the New England Journal of Medicine. [Link sic.]

And, from Devin: Adrien Treuille discusses the power of online, collaborative puzzle solving for Google’s “Solve for X.”