A small group of paleontologists (古生物学家) recently discovered 10 species of ancient mammals previously unknown to science with the help of an enormous number of helpers at their dig site: ants.

The study of ancient mammals sheds new light on the diversity of mammals that existed in North America around 33 million to 35 million years ago, when the climate was changing drastically. It also pays attention to the harvester ants, with which researchers have long had a love-hate relationship. “The ants are not fantastic when they’re biting you,” said Samantha Hopkins, a professor of Earth Sciences at the University of Oregon. “But I’ve got to appreciate them because they make my job a whole lot easier.”

Most species of harvester ants live in subterranean caves that sit beneath a small hill of dirt. They strengthen the dirt by covering it with bits of rock and other tough materials. The ants have been known to travel over a hundred feet from their caves and to dig six feet deep in pursuit of materials that help secure their caves. The materials include fossils. Harvester ants can carry materials 10 times to 50 times the weight of their body, although they do not weigh very much, so the heaviest fossil they can collect weighs less than the average pill.

Given the size, harvester ant hills are hot spots for what scientists call microvertebrate (微型脊椎动物) fossils, which are animal fossils too small to see without a microscope. For over a century, scientists like Dr. Hopkins have found sediment (沉积物) off the sides of harvester ant hills in search of these fossils, making it easier to find large numbers of fossilized mammal teeth without spending hours in the field sifting through sand and dirt.

Eva, the Belgian Malinois, is home now, getting a well-deserved rest surrounded by new toys after nearly dying while protecting her human from a mountain lion.

The attack happened on May 16 in northern California when 24-year-old Erin Wilson headed down a path toward the Trinity River before she found herself cornered by a mountain lion. “I was just walking down the slope with the dog running ahead of’ me. I turned around and there was this cat just growling at me and it attacked me, ”Wilson told NPR. “I screamed for Eva and she came running. ”

Mountain lion attacks on humans are incredibly rare. Since 1890, California has recorded only six fatal mountain lion attacks because of the animal’s generally shy, reclusive (独处的) nature. Their preferred prey is deer, which are normally in abundance in their forested habitat, but recent drought conditions have made food scarce in some areas. Wilson thought that these conditions made the sudden appearance of a slim woman look like an attractive option.

To protect her human, Eva leapt between Wilson and the lion, tackling the wild cat and embarked on a life-and-death struggle between the two animals. After a short fight, the mountain lion got its jaws around Eva’s head and Wilson fought to free her dog. hitting the lion with rocks in an attempt to break its grip. Eventually, Wilson ran back to her truck and flagged down passing motorist Sharon Houston Fetching an iron bar from her truck. Wilson and Houston ran back down the trail and their combined efforts managed to frighten the big cat off.

Wounded herself and shaken by the experience, Wilson still managed to carry Eva back to the Animal Hospital. The 2-year-old dog didn’t need surgery, but her wounds were still extensive. Eva left the animal hospital on May 19 with surgical tape wrapped around both her front paws, and the veterinarian said she might lose sight in her left eye.

On a sunny morning in 2001, Jim, a skilled diver and ocean lover, was diving as usual around Palm Beach in the Bahamas when he spotted a giant tiger shark circling a few feet away. The shark, which he later named Emma, was clearly struggling in pain. Seeing Jim, Emma swam close to him seemingly quite on purpose. With great fear and curiosity, Jim checked and found a fishing hook in Emma’s mouth. Despite the obvious risks, he managed to pull the hook out, careful not to cause any further injury to the animal. Jim has since removed four other hooks from Emma’s mouth on several occasions and sometimes freed her from fishing lines or plastic bags. The two have become inseparable.

Every time Jim goes into the water in the area of Palm Beach, Emma comes around and rubs her head against him as a sign of affection (喜爱). It’s not the kind of behavior most people would expect from tiger sharks, which could easily tear a person apart. “When you suddenly come across a huge shark, it seems like it might end your life,” Jim said. “What makes Emma so special is that she’s so loving and affectionate. She’s not a mindless killer but a sentient (有感情的) animal just like cats and dogs.”

Emma will always recognize Jim every time he dives in her area even if he changes diving equipment. Over time, she has learned his hand signals — an invitation to get her head rubbed and Jim claims that she started acting like a playful dog who loves being petted.

“What makes Emma so special is that she’s so loving and affectionate. She’s not a mindless killer but a sentient (有感情的) animal just like cats and dogs.” Jim said. “To have a connection that lasts the entire time you`re in the water is so moving and so influential. One of the best things that have happened to me is the discovery of the affectionate aspect of this tiger shark.”