Sloths are weird critters. Cute, in a certain light, but mostly weird. They’re members—with armadillos and anteaters—in a superorder of mammals called the Xenarthra, which are united by a unique form of multi-jointed vertebrae. Their diet consists mostly of leaves, which are poor quality food, and hard to digest. Fortunately, they also have one of the slowest, lowest-energy lifestyles of any mammal, using heavily modified limbs to hang upside down from branches while they browse, their most recent meal fermenting in their guts.
David Attenborough got up close with a sloth—which he calls a “mobile compost heap”—in The Life of Mammals. He also observes one of the sloth’s weirdest behaviors: to answer the call of nature, it climbs all the way down to the ground.
Why do sloths go to all that trouble—and risk—just to poop? Well, according to a recent paper in Proceedings of the Royal Society, they do it to feed poop-eating moths that help cultivate nutritious algae in their fur. No, but really.
Here at Nothing in Biology Makes Sense, we’re fascinated by all the weird, baroque ways that living things influence and coevolve with each other—so Ed Yong’s new TED talk about mind-controlling parasites is right up our alley. Just like his writing—currently on display at National Geographic‘s Phenomena, among many other venues—it’s a compendium of nifty natural history punctuated with highly educational gross-outs and the occasional black-belt level pun.
Welcome, readers, to the 57th Carnival of Evolution. This past month, the 204th birthday of Charles Darwin just happened to fall on Mardi Gras, a celebration of life’s exuberant excesses. So put on your most dazzling mask, and join us for an exploration of the endless forms most beautiful to be found in the living, evolving world.
In addition to Darwin Day and Mardi Gras, February is the month of Valentine’s Day. So it’s maybe appropriate that evolutionary bloggers had sex on the brain. Joachim describes new research on the specific forms of natural selection that might have supported the evolution of sexual reproduction. Right here at Nothing in Biology Makes Sense!, Amy Dapper writes about one consequence of sex, among grass gobies: “sneaker” males with specialized sperm. And Jeremy Yoder (yours truly) takes a look at daisies that attract pollinators by fooling them into mating with deceptive flower petals.
Meanwhile, Hannah Waters explains why sociable weaver birds nest together—because it pays to stay home and help their parents.
While most songbird species breed before they even turn a year old, sociable weavers rarely breed before the age of two. Instead, these younger birds help raise other nestlings–their siblings as well as unrelated chicks–by gathering food and maintaining the nest’s fluffy interior chambers and external sticks and grass.
President Obama at a rally in Lima, Ohio, on Friday.
Cross-posted from Denim and Tweed.
You may have heard that there’s an election happening in the United States today. It’s been ten months of “campaign season” since the early Republican party primary elections in Iowa and New Hampshire, and the two presidential campaigns and their various allies have raised and spent going on two billion (billion!) dollars on advertising and campaigning and probably also consultants’ fees.
This seems like an awfully expensive and inefficient way to choose someone to run a government, which is to say an awfully expensive and inefficient way to work together to decide upon and achieve common goals. Winston Churchill famously noted that democracy is the worst form of government “except all those other forms that have been tried from time to time.” But Churchill was really only talking about democracy in comparsion to other human forms of government. The living world contains all sorts of examples of individuals coordinating their actions for mutual benefit, and none of them need political action committees to do it.
Is there a better approach to group organization somewhere else on the tree of life? Let’s consider a few options:
Abita Springs, LA
Am I allowed to test post too!?!?!?