Photograph by Stefan Lovgren
Photograph by Stefan Lovgren

What are the biggest animals among us?

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By Rachael Bale, ANIMALS Executive Editor

The blue whale is the biggest animal in the world. The elephant is the biggest on land. And the whale shark is the biggest fish in the sea. But what about freshwater behemoths? According to the official record, it’s the Mekong giant catfish, with a single one weighing in at 646 pounds. But researchers have long suspected another freshwater species (pictured above) is the real heavyweight—the giant freshwater stingray, a car-size ray native to Southeast Asia. Scientists, and our reporter Stefan Lovgren, recently went to a small fishing village in Indonesia to check out reports of one weighing nearly 880 pounds.

There are giant freshwater fish on every continent except Antarctica. The amazing thing is that we know so little about most of them. With the giant stingray, for example, we don’t know how big they can really get, whether they can go into the ocean, or even whether they’re actually comprised of more than one species. One thing we do know for sure is that they’re in trouble. Global populations of large freshwater animals have plummeted since 1970. Let’s hope we can save them—we still have so much to learn about them.

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Maltreatment: Nat Geo’s Rachel Fobar and Nichole Sobecki went to this controversial lion-breeding farm/sport hunting grounds in South Africa. Three days later, visiting inspectors from the National Council for Societies for the Prevention of Cruelty to Animals found about 20 young lion and tiger carcasses in a freezer in a staff member’s home, a lion cub in a walk-in freezer, and, hidden in a shed, two live cubs also suffering from a neurological condition caused by malnutrition. Conservationists say the situation at Pienika Farm is not an isolated incident.

Read: Inside a controversial South African lion ‘farm'

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Today in a minute

Mussels collapse: Staggering numbers of freshwater mussels are dying across the United States and Europe, and no one knows why. The mussels have worked as a natural cleaner to rivers and streams. Without them, says wildlife disease expert Tony Goldberg, “the freshwater ecosystem will change forever.”

Resilient rats: We’re spending more and more money to eradicate rats, but rat populations are growing in major cities. Researchers ask: Are the rodents leading the way in swift evolutionary changes to survive?

Improving species: A gecko, a songbird, and a minnow are among 27 American species that recovered this year, Nat Geo’s Natasha Daly reports. At least 10 other species have improved conservation statuses elsewhere, ICUN says. Those species include the Australian trout cod, the Echo Parakeet of Mauritius, and the flightless, fast-running Guam Rail, only the second bird to recover after being declared extinct in the wild.

Homeless lemurs? Climate change and deforestation may eliminate the habitat for two of Madagascar’s lemur species by 2080, a new study says. The black-and-white ruffed lemurs and red-ruffed lemurs are only found on the Indian Ocean nation, and they’re among the 96 of the country’s 101 lemur species that are considered threatened by extinction.

The big takeaway

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One last glimpse

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Saving the pangolin: At the Tikki Hywood Foundation’s rescue center, in Zimbabwe, each pangolin—like Tamuda, seen here—is assigned a caretaker. The scaly, cat-sized, nocturnal mammals form close bonds with their humans, who help them learn how to feed on ants and termites. Rescued as a baby, Tamuda was stubborn and impish, his caretaker says. The threatened pangolins, heavily trafficked, got a break this year when Chinese health insurance dropped coverage for use of their scales in traditional medicine.

Related: Wildlife victories of the year

Correction: Last week, we had the image of the wrong sparrow species that was the center of pioneering work by ethologist and ornithologist Margaret Morse Nice. It should have been the song sparrow, shown here. Thanks to our avian-minded readers for pointing this out.

This newsletter has been curated and edited by David Beard, with photo selections by Eslah Attar. Have an idea or a link? We’d love to hear from you at