Welcome back to the Abstract! Here are the studies this week that ruled the roost, warmed the soul, and departed for intergalactic frontiers.
It will be a real creature feature this week. First, we will return to the realm of bats and discover that it is, in fact, still awesome. Then: poops from above; poops from the past; a very special bonobo; and last, why some dead stars are leaving the Milky Way in a hurry.
Bat hugs > Bear hugs
Welcome to The Real World: Bat Roost. Scientists installed a camera into a tree hollow in Guanacaste, Costa Rica to film a tight-knit family of four spectral bats (Vampyrum spectrum) over the course of several months. The results revealed many never-before-seen behaviors including bats hugging, playing with cockroaches, and even breaking the fourth wall.
“We provide the first comprehensive account of prey provision and other social behaviors in the spectral bat V. spectrum,” said researchers led by Marisa Tietge of Humboldt University in Berlin. “By conducting extensive video recordings in their roost, we aimed to document and analyze key behaviors.”
Spectral bats are the biggest bats in the New World, with wingspans that can exceed three feet. They are carnivorous—feasting on rodents, birds, and even other species of bat—and they mate in monogamous pairs, which is unusual for mammals. But while huge flesh-eating bats sound scary, the new study revealed that these predators have a soft side.
For example, the footage captured a “greeting” ritual that included “a hugging-like interaction between a bat already in the roost and a newly arrived bat,” according to the study.
“The resident bat may actively approach or greet the newcomer as it reaches close proximity in the main roosting area,” the team said. “The greeting behavior is comparable to the initiation to social roosting, where at least one bat wraps its wings around the other, establishing a ball-like formation for several seconds. This behavior is often accompanied by social vocalizations.”
There’s nothing like coming home after a graveyard shift to a warm welcome in a fuzzy ball-like formation. In keeping with their gregarious nature, the footage also showed that the bats are very generous with sharing prey, with only a single instance of a “tug-of-war” breaking out over dinner.
“Prey provision was a clearly cooperative social behavior wherein a bat successfully captured prey, brought it to the roost where group members were present, and willingly transferred the prey to another bat,” the researchers said. “Audible chewing noises are a distinctive feature of this process.”
Loud chewers in any other context are profoundly irritating, but these bats get a pass because it’s kind of hard to be quiet while crunching through mouse bones perched upside-down.
In addition to all the hugging and prey-sharing, the bats were also observed playing together by chasing cockroaches or, in one case, messing with the camera by altering its position. I can’t wait for the next season!
In other news…
Skyward scat
Speaking of putting cameras in weird places, why not strap them to the bellies of seabirds? Scientists went ahead and did this, ostensibly to examine the flight dynamics of streaked shearwaters, which are Pacific seabirds. But the tight focus on the bird-bums produced a different revelation: Shearwaters almost exclusively poop while on the wing.
“A total of 195 excretions were observed from 35.9 hours of video data obtained from 15 streaked shearwaters,” said authors Leo Uesaka and Katsufumi Sato of the University of Tokyo. “Excretion immediately after takeoff was frequent, with 50 percent of the 82 first excretion events during the flying periods occurring within 30 seconds after take-off and 36.6 percent within 10 seconds.”
“Occasionally, birds took off, excreted, and returned to the water within a minute; these take-offs are speculated to be only for excretion,” the team continued. “These results strongly suggest that streaked shearwaters intentionally avoid excretion while floating on the sea surface.”
This preference for midair relief might allow seabirds to lighten their load, prevent backward contamination, and avoid predators that sniff out excrement. Whatever the reason, these aerial droppings provide nutrients to ocean ecosystems, so bombs away.
Please clean up after your 9,000-year-old dog
Hold onto your butts, because we’re not done with scatological science yet. A study this week stepped into some very ancient dog doo recovered from a frozen site on Siberia’s Zhokhov Island, which was inhabited by Arctic peoples 9,000 years ago.
By analyzing the “paleofeces,” scientists were able to reconstruct the diet of these canine companions, which were bred in part as sled dogs. The results provide the first evidence of parasites in Arctic dogs of this period, suggesting that the dogs were fed raw fish, reindeer, and polar bear.
“The high infection rate in dogs with diphyllobothriasis indicates a significant role of fishing in the economic activities of Zhokhov inhabitants, despite the small amount of direct archaeological evidence for this activity,” said researchers led by S.M. Slepchenko of Tyumen Scientific Center. “The presence of Taeniidae eggs indicates that dogs were fed reindeer meat.”
The team also noted that after excavation, the excrement samples were “packaged entirely in a separate hermetically sealed plastic bag and labeled.” It seems even prehistoric dog poop ends up in plastic bags.
Kanzi the unforgettable bonobo
Playing hide-and-seek with bonobos is just plain fun, but it also doubles as a handy experiment for testing whether these apes—our closest living relatives—can track the whereabouts of people, even when they are out of sight.
Kanzi, a bonobo known for tool use and language skills, participated in experiments in which his caretakers hid behind screens. He was asked to identify them from pictures or voices and succeeded more than half the time, above chance (here’s a video of the experiment).
”Kanzi presented a unique and powerful opportunity to address our question in a much more straightforward way than would be possible with almost any other ape in the world,” said authors Luz Carvajal and Christopher Krupenye of Johns Hopkins University. “He exhibited not only strong engagement with cognitive tasks but also rich forms of communication with humans—including pointing, use of symbols, and response to spoken English.”
Sadly, this was one of Kanzi’s last amazing feats, as he died in March at the age of 44 in his long-time home at the Ape Initiative in Des Moines, Iowa. But as revealed by this posthumous study, Kanzi’s legacy as a cognitive bridge between apes lives on. RIP to a real one.
Zero to 4.5 million mph in a millisecond
We will close with dead stars that are careening out of the galaxy at incomprehensible speeds. These objects, known as hypervelocity white dwarfs, are corpses of stars similar in scale to the Sun, but it remains unclear why some of them fully yeet themselves into intergalactic space.
“Hypervelocity white dwarfs (HVWDs) are stellar remnants moving at speeds that exceed the Milky Way’s escape velocity,” said researchers co-led by Hila Glanz and Hagai B. Perets of the Technion–Israel Institute of Technology. “The origins of the fastest HVWDs are enigmatic, with proposed formation scenarios struggling to explain both their extreme velocities and observed properties.”
The team modeled a possible solution that involves special white dwarfs with dense carbon-oxygen cores and outer layers of helium, known as hybrid helium-carbon-oxygen (HeCO) white dwarfs. When two He-CO white dwarfs merge, it may trigger a “double-detonation explosion” that launches one of the objects to speeds of about 4.5 million miles per hour.
“We have demonstrated that the merger of two HeCO white dwarfs can produce HVWDs with properties consistent with observations” which “provides a compelling explanation for the origin of the fastest HVWDs and sheds new light on the diversity of explosive transients in the Universe,” the researchers concluded.
With that, may you sail at hypervelocity speeds out of this galaxy and into the weekend.
Thanks for reading! See you next week.
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