Scientists have successfully recovered RNA, a form of genetic material, from the remains of the Tasmanian tiger, an extinct Australian animal. The discovery could help scientists learn more about these creatures before they disappeared from Earth.

The researchers extracted the recovered RNA from the skin and muscle of a Tasmanian tiger specimen (标本) stored in a Swedish museum since 1891. This is the first time RNA has been successfully recovered from an extinct animal. The Tasmanian tiger was once a top predator, known for hunting kangaroos and other animals. The last known Tasmanian tiger is believed to have died in a Tasmanian zoo in 1936. Emilio Mármol Sánchez, from the Centre for Palaeogenetics, led the study describing these research results. Sánchez believes that the recovered RNA material provides a glimpse into the true biology of the Tasmanian tiger, offering insights into the cells and tissues of these extinct creatures.

While Scientists have in recent years taken RNA from different ancient animals and plants, how long RNA could survive at room temperature has been a subject of debate among researchers. The well-preserved condition of the Tasmanian tiger remains, which were in a state of semi-mummification (半木乃伊化), suggests that RNA can survive for longer periods under certain conditions.

The Tasmanian tiger looked similar to a wolf, except for the tiger-like lines appearing on its back. When people arrived in Australia about 50,000 years ago, large animal population losses followed. The arrival of European colonizers in the 18th century destroyed the remaining populations around the island of Tasmania.

Private “de-extinction” programs have been launched with the aim of bringing back some extinct animals. These include the Tasmanian tiger, flightless dodo bird and wooly mammoth.

However, many researchers have warned about the difficulties of using genetic processes to actually recreate an extinct species. While Sánchez said he too has concerns about such processes, he noted that he does “advocate for more research on the biology of these extinct animals.”

From 2018 to 2021, about 10 billion snow crabs (蟹) disappeared from the eastern Bering Sea off the coast of Alaska. “It’s a fishery disaster in the truest sense of the word,” says Cody Szuwalski, a fishery biologist.

Usually, as winter’s thick sea ice melts (融化), the meltwater settles on the seafloor, creating a cold-water pool with temperatures below 2° Celsius on the eastern Bering Sea shelf, which makes perfect habitat for snow crabs. But a sea heat wave in the area in 2018 and 2019 prevented the usual amount of sea ice from forming.

After a close study, Szuwalski and his colleagues have found the water temperature probably didn’t kill the crabs directly, as snow crabs in laboratories can survive in waters up to 12℃. Instead, the crabs might have died from hunger. According to the study, the food demand of snow crabs in labs almost double as water temperature rises from 0℃ to 3℃. The crab population reached historic highs in 2018 thanks to great ocean conditions for newborn crabs around 2010. As a result, the crowded crabs probably needed more food, but because of the smaller foraging (觅食) area, they had even fewer resources to sink their claws into.

“It’s just something we didn’t expect, but now we have to live with,” says Christopher Harley, an ocean scientist. Such effects of ocean heat waves are likely to go beyond snow crabs. In answer to climate change, ecosystems in northern areas of the earth, such as Alaska’s, are changing more rapidly than anywhere else. Scientists can try to help predict (预测) and prepare for changes in the future with the aid of former research. “But the future increasingly holds events that have never happened on record before, like the drop in the snow crab population,” Harley says.

A shop owner placed a sign above his door that said: “Puppies for Sale.” Signs like this always have a way of attracting young children, and to no surprise, a boy saw the sign and approached the owner.

“How much are you going to sell the puppies for?” he asked.

The shop owner replied, “Anywhere from $30 to $50.”

The little boy pulled out some change from his pocket. “I have $2.37,” he said. “Can I please look at them?”

The shop owner smiled and whistled. A lady ran down the aisle of his shop followed by five tiny balls of fur.

One puppy was lagging considerably behind. Immediately the little boy singled out the lagging puppy and said, “What’s wrong with that little dog?”

The shop owner explained that the puppy was born disabled and it would always be lame. The little boy became excited. “I’ll buy it.” The shop owner said, “No, you don’t want to buy that little dog. If you really want him, I’ll just give him to you.” The little boy looked straight into the shop owner’s eyes and said, “I don’t want you to give him to me. That little dog is worth every bit as much as all the other dogs and I’ll pay full price. In fact, I’ll give you $2.37 now, and 50 cents a month until I pay it off.”

The shop owner countered, “You really don’t want to buy this little dog. He is never going to be able to run and play with you like the other puppies.”

To his surprise, the little boy reached down and rolled up his pant leg to reveal a badly twisted, crippled left leg supported by a big metal brace. He looked up at the shop owner and softly replied, “Well, I don’t run so well myself, and the little puppy will need someone who understands!”