Episodic memory (情景记忆) allows humans to revisit past personal experiences in their minds, and it was once thought to be a special skill of humans. Although there are still arguments about the extent of this type of memory in non-human animals, scientists have proved that creatures like rats and dogs can pass tests that are developed to assess episodic memory over the past two decades. “Curiously, there is a lack of research investigating dolphins’ episodic memory,” University of Cambridge cognitive (认知的) scientist James Davies says. Therefore, this surprising fact encourages him to fill this gap.

The team used “where” and “who” questions in their research, each on a different test. Each dolphin was first trained to retrieve a ball from the water, and then trained to get a ball by approaching a person holding it in front of them while ignoring an empty-handed person standing at a different spot. During this training, the locations were randomized (使随机化) and the person holding the ball differed each time, so that those details were irrelevant to learning the retrieving behavior. Then, for the tests, the dolphins were asked to retrieve the ball as they had learned to do, but after 10 minutes, something changed-this time, the ball couldn’t be seen, as it was now behind one of the two people’s backs. In the “where” tests, the ball was hidden in the same spot as in the training, but both people had been changed, while in the “who” tests, the locations of the people changed but the ball remained with the person who’d had it previously.

Eight dolphins went through each of the two tests, separated by at least 48 hours. All the dolphins got it right in choosing the correct spot on the “where” experiments, and seven achieved success on the “who” experiments.

Kelly Jaakkola, a psychologist, says that based on their cognitive skills, dolphins are a good candidate for having episodic-like memory, and this study goes really far in showing that. She also says, “The more we look for such capabilities in non-human animals, the more species we’ll likely find them in.” She adds, “An exciting question is therefore ‘Where do we draw that line? Which animals do have it, which animals don’t, and what sort of cognitive or neurological or social characteristics do those animals share? ’ That’s going to be the fun part of the game.”

Harry, the first camel to arrive in Australia in 1840, was an unlucky beast. He was imported from the Canary Islands by explorer John Horrocks. On an expedition（探险），Horrocks picked up his gun in order to shoot "a beautiful bird to be added to the collection.” Perhaps Harry was an ecologist—he lurched（突然倾斜）, and the gun discharged, shooting Horrocks in the face.

Horrocks not surprisingly died of his injuries, and his teammates ordered Harry to be shot. The first importation of a camel into Australia came to naught.

At the beginning of 1860, 24 camels arrived in Australia to be part of an expedition by explorers Robert O'Hara Burke and William John Wills. It was an unlucky expedition. The pair made one mistake after another, and ended up eating most of their camels within several months, before starving to death.

Six years later, more than 100 camels and their Afghan minders arrived in Australia. This time it succeeded and thousands more camels followed.

Sir Thomas Elder set up the first camel studs（种畜场）in South Australia, while others were set up in Western Australia. This time the camels bred（繁殖）like wildfire. They were used for working, rather than exploring expeditions.

The imported Afghan cameleers（骆驼夫）were just as hardy and vital, leading camel trains across the cruel interior（腹地）of Australia, where few dared Io go. The camels carried heavy packs of wool and supplies and opened up the desert areas as none had managed to do before. The train that does this crossing today is called The Ghan, in their honor.

Motorization put these camel trains out of business, and many camels were turned loose. The camels loved Australia, and multiplied in amazing numbers. What is to be done with them?

Not surprisingly they have become quite a tourist attraction and you can take a camel ride in the desert as the Afghan cameleers once did. But the fact is that camels create quite a problem in areas where they have taken over, as they damage local vegetation, muscle out native animals competing for food, and create chaos when they wander into settled area.

Mutualism—win-win ecological partnerships perfected over evolutionary time-lengths—is a less-known ecological relationship that is also weak and easily hurt by the effect of a rapidly changing planet.

Bees and flowers are typical examples of mutualism. Some bee tongues are perfectly evolved to tap into certain flowers. By specializing in those plants, the longer-tongued bees reduce competition with insects that can't access those sweet foods.

That mutualistic relationship, however, has been impacted in at least one population of bees and flowers. As certain flowers in Colorado have become rarer due to warming temperatures, the tongues of the bumblebees（大黄蜂）that historically fed on them have become shorter.

Like many of their relatives, bumblebees are on the decline. To find out what's going on, a team of researchers headed to Colorado. The researchers examined bumblebee samples collected on three mountains from 1966 to 1980 and also gathered a fresh set, which they collected in the same places from 2012 to 2014. They performed the task of measuring all the historic and recently caught bees' tongues.

As the team reports in Science, both of the species tongues have declined in length over time. The team found a nearly 25-percent decrease in tongue length between the bees collected decades ago and those living in the same region today.

Next they turned to the flowers. Looking at contemporary and historic botanical data, the scientists confirmed that the number of flowers with short tubes did not increase in large quantities. They found that in response to warmer temperatures, flowers have been moving up the mountains and becoming rarer at lower altitudes. This altitude-climbing effect has ultimately resulted in an approximate loss of millions of flowers.

The findings paint a telling picture: hotter summers caused bumblebees' choice flower species to disappear, forcing them to evolve shorter tongues to tap into the remaining food sources. Then, competition with generalist species, more time and energy needed and a forced reliance on alternative sources all likely contributed to the bees' overall decline.