Paleontologists in California announced this week that fossils excavated in the early 2000s represent four new species of ancient whales. The toothed baleen whales apparently stuck around longer than scientists once thought, and they may hold clues about how and when whales evolved from toothy giants to the baleen-equipped beasts we see today.
Though the slogan “Save the Whales” has, these days, something of a sepia-toned sound to it, we aren’t doing a terribly good job of it, a new study suggests. In the last 40 years, the study says, humans were implicated in the majority of whale deaths with known causes. Read More
Blue whales, the largest animals on Earth, can eat about four tons of food a day—and when they’re done digesting, there’s still a whole lot of stuff left over. This aerial shot, taken by oceanographic consultant Eddie Kisfaludy off the Southern California coast, shows a blue whale and a truly enormous plume of its poop, the same vibrant orange as the krill on which the whales feed.
Whale feces, it turns out, plays a substantial role in ocean ecosystems. Since it floats to the surface, it brings nitrogen whales have taken in when they fed in the ocean’s depths to shallow waters, providing a much-needed nutrient for plankton there. The massive mammals’ poop also serves as a significant carbon sink; one study estimated that excrement from sperm whales in the Southern Ocean alone sequestered 400,000 tons of carbon dioxide a year.
Creatures as large as elephants are unusual; it takes a long time to evolve such size.
How long does it take for a mammal as small as a mouse to evolve into something as large as an elephant? A really, really long time, a recent study has found: about 24 million generations, at minimum.
To get that number, researchers looked at the evolution of body mass over the last 70 million years, after the dinosaurs went extinct and surviving animals expanded into the ecological niches they left behind. That estimate is far longer than earlier estimates, which, extrapolating from bursts of super-fast evolution in mice, range from just 200,000 to 2 million generations. Such speedy evolution, in actuality, is probably not sustainable over the long term—hence the lengthy new estimate.
Three-dimensional model of an ancient whale skull.
What’s the News: Scientists have long held that archaeocetes, the precursors to modern cetaceans, had symmetrical skulls like most other mammals. Whale skulls only became asymmetrical as certain species evolved echolocation to hunt for food. But it turns out that archaeocetes actually had skewed skulls, which likely allowed the whales to hear better underwater, according a new study published in the journal PNAS.
The anti-whaling movement hit its peak in 1986, when the International Whaling Commission banned all commercial whaling. Despite the ruling, however, the privately funded Institute of Cetacean Research in Japan has continued whaling by exploiting a loophole in the moratorium that allows some whaling for research purposes. But now, in a report by the government-run Fisheries Agency of Japan, the country has publicly considered ending its whaling efforts in the Antarctic Ocean (aka Southern Ocean), according to Yomiuri Shimbun, one of Japan’s five national newspapers.
It takes a tremendous amount of energy to move the largest animal on Earth from a standstill to chasing food in a fierce dive. Could the krill that a blue whale catches in its gargantuan mouth really provide a high enough calorie count to make all this effort worthwhile? To find out, Jeremy Goldbogen tagged whales with data recorders and monitored hundreds of their dives. It can take 770 to 1900 calories to get the whale moving, but it’s worth it.
When Goldbogen plugged the data from his recorders into a simulation of a feeding whale, he found that the lunge is staggeringly efficient. Despite the massive outlay in energy, the whale easily recoups anywhere from 6 to 240 times that amount, depending on how big it is and how tightly packed its krill targets are.
If a big whale attacks a particularly dense swarm, it can swallow up to 500 kilograms of krill, eating 457,000 calories in a single monster mouthful and getting back almost 200 times the amount it burned in the attempt. A smaller whale lunging at a sparse collection of krill would only get around 8,000 calories, but that’s still 8 times more than what it burned. Even when Goldbogen accounted for the energy needed to dive in search of prey, the whales still regained 3 to 90 times as much energy as they spent.
Not Exactly Rocket Science: Across an ocean, round a continent – the epic 10,000km voyage of a humpback whale
Not Exactly Rocket Science: Behold Livyatan: the sperm whale that killed other whales
80beats: Climate Scientists Enlist Narwhals to Study the Arctic Ocean
Image: Wikimedia Commons
Whales don’t wear sunscreen. And because these massive sea mammals must surface to breathe, they are being exposed to more and more ultraviolet radiation sneaking through the weakened ozone layer. According to Karina Acevedo-Whitehouse, lead author of a study in the Proceedings of the Royal Society B, some whales are getting serious sunburns at an alarming rate.
From 2007 to 2009, her team sampled fin, sperm, and blue whales in the sun-drenched Gulf of California, which is the long, skinny expanse of water between mainland Mexico and Baja California.
Nearly all of the skin samples contained “sunburn cells,” abnormal cells associated with ultraviolet-induced DNA damage. These indicators were even found in the lowest layer of skin on the whales, suggesting that those individuals were suffering from very severe sunburns. [Discovery News]
The newest climate researchers are those one-horned wonders of the sea, narwhals. Researchers recruited these marine mammals to gather data about ocean temperatures in Baffin Bay, an icy stretch of the Arctic between northern Canada and Greenland. The project was a collaboration between several climate scientists and marine biologist Kristin Laidre, who declared the experiment a success.
“Narwhals proved to be highly efficient and cost-effective ‘biological oceanographers,’ providing wintertime data to fill gaps in our understanding of this important ocean area,” said Laidre. [Discovery News]
Researchers were eager for assistance, because the difficulty of gathering data in the Arctic winter had led to a hole in the climate data. Says study coauthor and oceanographer Mike Steele:
From Ed Yong:
On 7 August 1999, a lucky photographer snapped a female humpback whale frolicking off the east coast of Brazil. Two years later, on 21 September 2001, the same whale was caught on camera again, by a tourist on a whale-watching boat. But this time, she was a quarter of the world away, off the eastern coast of Madagascar. The two places where she was spotted are at least 9800 kilometres apart, making her voyage the longest of any mammal.
In American terms, that means the adventurous humpback had taken a trip of about 6,000 miles. Read the rest of the post–including info about how scientists are sure they were looking at the same whale both times–at Not Exactly Rocket Science.
80beats: Lady Humpback Whales Make Friends & Meet up for Summer Reunions
80beats: Cacophony in the Oceans May Confuse Whales and Drown Out Their Songs
80beats: Tiny Tern Makes World-Record 44,000-Mile Migration
80beats: Tiny Bird Backpacks Reveal the Secrets of Songbird Migration
80beats: Migrating Marine Animals May Follow Magnetic Fields to Find Their Homes