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Illustration by Marlin Peterson
Illustration by Marlin Peterson

Enormous Prehistoric Birds May Have Roamed the Canadian Arctic

Illustration by Marlin Peterson
Illustration by Marlin Peterson

An enormous bird terrorized the shrubs of northern Canada around 53 million years ago. Researchers say fossil evidence of the flightless bird Gastornis was found in the Canadian Arctic—much further north than anywhere the creature had been found before. The findings were recently published in the journal Scientific Reports. 

We’ve known about Gastornis for quite some time now, but previous fossils have all been discovered further south, in Wyoming, Europe, and Asia. For many years, paleontologists believed the six-foot-tall bird with a horse-sized head was a carnivore. More recent research suggested that Gastornis’s monstrous beak was used for tearing leaves, nuts, and fruits off of plants. That’s right: this nightmare bird was a vegan. 

Paleontologists found a large, fossilized phalanx (toe bone) on Canada’s Ellesmere Island in the 1970s. The bone looked like it might have belonged to Gastornis, so they recorded it as such, then put it away. The bone lay unexamined for decades until integrative biologist Thomas Stidham and geologist Jaelyn Eberle took an interest. 

“We knew there were a few bird fossils from up there, but we also knew they were extremely rare,” Eberle said in a press release.

So did this toe really belong to Gastornis? Eberle and Stidham compared the Ellesmere Island bone to those found earlier in Wyoming. The bones were not only nearly identical, but very close in age. 

The researchers also took a closer look at an Ellesmere Island humerus (wing bone) assumed to have belonged to the lanky, extinct bird, Presbyornis. That, too, was a match with Presbyornis bones found elsewhere. “I couldn’t tell the Wyoming specimens from the Ellesmere specimen, even though it was found roughly 4000 kilometers (2500 miles) to the north,” Stidham said in the press release. 

As always, it is worth noting that these conclusions were drawn from a single bone of a single animal, and therefore amount to highly educated guesses about what these birds looked like, how they behaved, and what they ate. 

Stidham and Eberle say their findings have implications for climate change. Although Ellesmere Island today is frozen solid, it was likely much warmer during the Eocene Epoch, making it more hospitable for prehistoric reptiles, primates, and birds like Gastornis and Presbyornis. They say that while Gastornis may have lived at Ellesmere throughout the winter, they're not sure whether Presbyronis migrated there or took up residence year-round.  

The Earth is warming again. “Permanent Arctic ice, which has been around for millennia, is on track to disappear,” Eberle said. “I’m not suggesting there will be a return of alligators and giant tortoises to Ellesmere Island any time soon. But what we know about past warm intervals in the Arctic can give us a much better idea about what to expect in terms of changing plant and animal populations there in the future.” 

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Ted Cranford
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science
Scientists Use a CT Scanner to Give Whales a Hearing Test
Ted Cranford
Ted Cranford

It's hard to study how whales hear. You can't just give the largest animals in the world a standard hearing test. But it's important to know, because noise pollution is a huge problem underwater. Loud sounds generated by human activity like shipping and drilling now permeate the ocean, subjecting animals like whales and dolphins to an unnatural din that interferes with their ability to sense and communicate.

New research presented at the 2018 Experimental Biology meeting in San Diego, California suggests that the answer lies in a CT scanner designed to image rockets. Scientists in San Diego recently used a CT scanner to scan an entire minke whale, allowing them to model how it and other whales hear.

Many whales rely on their hearing more than any other sense. Whales use sonar to detect the environment around them. Sound travels fast underwater and can carry across long distances, and it allows whales to sense both predators and potential prey over the vast territories these animals inhabit. It’s key to communicating with other whales, too.

A CT scan of two halves of a dead whale
Ted Cranford, San Diego State University

Human technology, meanwhile, has made the ocean a noisy place. The propellers and engines of commercial ships create chronic, low-frequency noise that’s within the hearing range of many marine species, including baleen whales like the minke. The oil and gas industry is a major contributor, not only because of offshore drilling, but due to seismic testing for potential drilling sites, which involves blasting air at the ocean floor and measuring the (loud) sound that comes back. Military sonar operations can also have a profound impact; so much so that several years ago, environmental groups filed lawsuits against the U.S. Navy over its sonar testing off the coasts of California and Hawaii. (The environmentalists won, but the new rules may not be much better.)

Using the CT scans and computer modeling, San Diego State University biologist Ted Cranford predicted the ranges of audible sounds for the fin whale and the minke. To do so, he and his team scanned the body of an 11-foot-long minke whale calf (euthanized after being stranded on a Maryland beach in 2012 and preserved) with a CT scanner built to detect flaws in solid-fuel rocket engines. Cranford and his colleague Peter Krysl had previously used the same technique to scan the heads of a Cuvier’s beaked whale and a sperm whale to generate computer simulations of their auditory systems [PDF].

To save time scanning the minke calf, Cranford and the team ended up cutting the whale in half and scanning both parts. Then they digitally reconstructed it for the purposes of the model.

The scans, which assessed tissue density and elasticity, helped them visualize how sound waves vibrate through the skull and soft tissue of a whale’s head. According to models created with that data, minke whales’ hearing is sensitive to a larger range of sound frequencies than previously thought. The whales are sensitive to higher frequencies beyond those of each other’s vocalizations, leading the researchers to believe that they may be trying to hear the higher-frequency sounds of orcas, one of their main predators. (Toothed whales and dolphins communicate at higher frequencies than baleen whales do.)

Knowing the exact frequencies whales can hear is an important part of figuring out just how much human-created noise pollution affects them. By some estimates, according to Cranford, the low-frequency noise underwater created by human activity has doubled every 10 years for the past half-century. "Understanding how various marine vertebrates receive and process low-frequency sound is crucial for assessing the potential impacts" of that noise, he said in a press statement.

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Scientific Reports, Fernando Ramirez Rozzi
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Stones, Bones, and Wrecks
Humans Might Have Practiced Brain Surgery on Cows 5000 Years Ago
Scientific Reports, Fernando Ramirez Rozzi
Scientific Reports, Fernando Ramirez Rozzi

In the 1970s, archaeologists discovered a site in France containing hundreds of cow skeletons dating back 5000 to 5400 years. The sheer number wasn't surprising—human agriculture in that part of the world was booming by 3000 BCE. What perplexed scientists was something uncovered there a few decades later: a cow skull bearing a thoughtfully drilled hole. Now, a team of researchers has released evidence that suggests the hole is an early example of animal brain surgery.

Fernando Ramírez Rozzi, a paleontologist with the French National Center for Scientific Research, and Alain Froment, an anthropologist at the Museum of Mankind in Paris, published their findings in the journal Nature Scientific Reports. After comparing the opening to the holes chiseled into the skulls of humans from the same era, they found the bones bore some striking similarities. They didn't show any signs of fracturing from blunt force trauma; rather, the hole in the cow skull, like those in the human skulls, seemed to have been carved out carefully using a tool made for exactly that purpose. That suggests that the hole is evidence of the earliest known veterinary surgery performed by humans.

Trepanation, or the practice of boring holes into human skulls, is one of the oldest forms of surgery. Experts are still unsure why ancient humans did this, but the level of care that went into the procedures suggests that the surgery was likely used to treat sick patients while they were still alive. Why a person would perform this same surgery on a cow, however, is harder to explain.

The authors present a few theories, the first being that these ancient brain surgeons were treating a sick cow the same way they might treat a sick human. If a cow was suffering from a neural disease like epilepsy, perhaps they though that cutting a hole in its head would relieve whatever was agitating the brain. The cow would have needed to be pretty special to warrant such an effort when there were hundreds of healthy cows living on the same plot of land, as evidenced by the skeletons it was found with.

Another possible explanation was that whoever operated on the cow did so as practice to prepare them for drilling into the heads of live humans one day. "Cranial surgery requires great manual dexterity and a complete knowledge of the anatomy of the brain and vessel distribution," the authors write in the study. "It is possible that the mastery of techniques in cranial surgery shown in the Mesolithic and Neolithic periods was acquired through experimentation on animals."

Either way, the bovine patient didn't live to see the results of the procedure: The bone around the hole hadn't healed at all, which suggests the cow either died during surgery or wasn't alive to begin with.

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