Scientists Think They Know How Whales Got So Big

iStock
iStock

It can be difficult to understand how enormous the blue whale—the largest animal to ever exist—really is. The mammal can measure up to 105 feet long, have a tongue that can weigh as much as an elephant, and have a massive, golf cart–sized heart powering a 200-ton frame. But while the blue whale might currently be the Andre the Giant of the sea, it wasn’t always so imposing.

For the majority of the 30 million years that baleen whales (the blue whale is one) have occupied the Earth, the mammals usually topped off at roughly 30 feet in length. It wasn’t until about 3 million years ago that the clade of whales experienced an evolutionary growth spurt, tripling in size. And scientists haven’t had any concrete idea why, Wired reports.

A study published in the journal Proceedings of the Royal Society B might help change that. Researchers examined fossil records and studied phylogenetic models (evolutionary relationships) among baleen whales, and found some evidence that climate change may have been the catalyst for turning the large animals into behemoths.

As the ice ages wore on and oceans were receiving nutrient-rich runoff, the whales encountered an increasing number of krill—the small, shrimp-like creatures that provided a food source—resulting from upwelling waters. The more they ate, the more they grew, and their bodies adapted over time. Their mouths grew larger and their fat stores increased, helping them to fuel longer migrations to additional food-enriched areas. Today blue whales eat up to four tons of krill every day.

If climate change set the ancestors of the blue whale on the path to its enormous size today, the study invites the question of what it might do to them in the future. Changes in ocean currents or temperature could alter the amount of available nutrients to whales, cutting off their food supply. With demand for whale oil in the 1900s having already dented their numbers, scientists are hoping that further shifts in their oceanic ecosystem won’t relegate them to history.

[h/t Wired]

Scientists Find Fossil of 150-Million-Year-Old Flesh-Eating Fish—Plus a Few of Its Prey

M. Ebert and T. Nohl
M. Ebert and T. Nohl

A fossil of an unusual piranha-like fish from the Late Jurassic period has been unearthed by scientists in southern Germany, Australian news outlet the ABC reports. Even more remarkable than the fossil’s age—150 million years old—is the fact that the limestone deposit also contains some of the fish’s victims.

Fish with chunks missing from their fins were found near the predator fish, which has been named Piranhamesodon pinnatomus. Aside from the predator’s razor-sharp teeth, though, it doesn’t look like your usual flesh-eating fish. It belonged to an extinct order of bony fish that lived at the time of the dinosaurs, and until now, scientists didn’t realize there was a species of bony fish that tore into its prey in such a way. This makes it the first flesh-eating bony fish on record, long predating the piranha. 

“Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time,” Dr. Martina Kölbl-Ebert, the paleontologist who found the fish with her husband, Martin Ebert, said in a statement. “Sharks have been able to bite out chunks of flesh, but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later."

Kölbl-Ebert, the director of the Jura Museum in Eichstätt, Germany, says she was stunned to see the bony fish’s sharp teeth, comparing it to “finding a sheep with a snarl like a wolf.” This cunning disguise made the fish a fearful predator, and scientists believe the fish may have “exploited aggressive mimicry” to ambush unsuspecting fish.

The fossil was discovered in 2016 in southern Germany, but the find has only recently been described in the journal Current Biology. It was found at a quarry where other fossils, like those of the Archaeopteryx dinosaur, have been unearthed in the past.

[h/t the ABC]

These Are America's 50 Most Rat-Infested Cities

iStock.com/Pierre Aden
iStock.com/Pierre Aden

New York City, home to the subway pizza rat, is surprisingly not America’s most rodent-infested city. That dubious honor goes to Chicago, according to a new analysis spotted by Thrillist.

A breakdown of the “50 Rattiest Cities” in the U.S. has been compiled by Orkin, a pest control service with locations across the country. The company tallied up the number of commercial and residential rodent treatments it carried out in each city over a period of 12 months (September 15, 2017 to September 15, 2018) and then ranked them. While the evidence is anecdotal, as it comes from just one company, it does reveal the areas where rat exterminators are in high demand.

This is the fourth year in a row that Chicago has been named the country’s rattiest city. Orkin isn’t the first to notice the city’s rodent problem, either. In July, Chicago was reportedly dubbed the “rat capital of the U.S.” by apartment search service RentHop. It reportedly received more rat complaints than any other city last year—nearly 51,000 total. According to RentHop’s analysis, New York City came in second place, followed by Washington, D.C. and Boston.

That isn’t too far off from Orkin’s latest analysis. New York comes in at third place, just after Los Angeles, and Washington, D.C. is fourth. The biggest boom in rat populations was seen in Portland, Maine, which jumped 19 spots from last year. Chance Strandell, residential service manager for Maine Pest Solutions, told New England Cable News that milder winters may be extending the rats’ breeding period. However, it’s unclear why rats seem to be multiplying in Maine in particular.

One pregnant rat can birth up to 12 babies in a single litter, and those pups can begin reproducing at just two months old. “So after a year, a busy pair of rat parents can have 15,000 descendants,” reports KATU in Portland, Oregon (number 24 on Orkin’s list).

Charleston, West Virginia, has also been teeming with rodents, having risen 17 spots from last year. Check out the full list of the 50 most rat-ridden cities below—and if you have musophobia (a fear of rats or mice), you may want to plot your move to one of the cities toward the bottom of the list.

1. Chicago, Illinois
2. Los Angeles, California
3. New York, New York
4. Washington, DC
5. San Francisco, California
6. Detroit, Michigan
7. Philadelphia, Pennsylvania
8. Cleveland, Ohio
9. Baltimore, Maryland
10. Denver, Colorado
11. Minneapolis-St. Paul, Minnesota
12. Dallas-Fort Worth, Texas
13. Boston, Massachusetts
14. Seattle, Washington
15. Atlanta, Georgia
16. Indianapolis, Indiana
17. Miami-Fort Lauderdale, Florida
18. Hartford, Connecticut
19. Pittsburgh, Pennsylvania
20. Cincinnati, Ohio
21. Milwaukee, Wisconsin
22. Charlotte, North Carolina
23. Houston, Texas
24. Portland, Oregon
25. Columbus, Ohio
26. San Diego, California
27. Raleigh-Durham, North Carolina
28. Buffalo, New York
29. New Orleans, Louisiana
30. Norfolk, Virginia
31. Richmond, Virginia
32. Albany, New York
33. Kansas City, Missouri
34. Portland, Maine
35. Nashville, Tennessee
36. St. Louis, Missouri
37. Sacramento, California
38. Greenville, South Carolina
39. Grand Rapids, Michigan
40. Phoenix, Arizona
41. Orlando, Florida
42. Tampa, Florida
43. Burlington, New York
44. Champaign, Illinois
45. Rochester, New York
46. Syracuse, New York
47. Charleston, West Virginia
48. Dayton, Ohio
49. Memphis, Tennessee
50. Flint, Michigan

[h/t Thrillist]

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