Parrots live extremely long partly due to their relatively large brains, an international team of researchers has discovered. Simeon Smeele, a doctoral student at the Max Planck Institute of Animal Behavior, led the study, the results of which were published in March in the Proceedings of the Royal Society B.

When it comes to lifespan (寿命), birds truly stand out. Lifespan tends to increase with an   animal’s body size, roughly speaking. Thus, the bigger the animal, the longer they live. But a bird tends to live much longer than a comparably-sized mammal (哺乳动物). One theory is that birds’ ability to fly means they are less at risk from the animals that kill them, which reduces their risk of being eaten, decreases stress, and frees up bodily resources for growth.

And among birds, parrots are the aging champions. The confirmed longest living bird was Cookie, a Major Mitchell’s cockatoo (a species of parrot), who lived at the Brookfield Zoo in Illinois for all but one of his 83 years. Though cockatoos often weigh around a pound, they usually live for four decades. Most of the other 398 parrot species also live longer than other birds of similar size.

What sets parrots apart? In the new research, Smeele and his colleagues gathered data on over 130,000 individual parrots held in more than 1,000 zoos, representing 217 species. Through this data, they created reliable estimates of the average lifespan for each species. They next searched for a link between each species’ lifespan and its relative brain size and found a clear, positive correspondence. Parrot species with larger brains relative to their body size lived longer than species with smaller brains.

“This supports the idea that in general larger brains make species more flexible and allow them to live longer,” Smeele said in a statement. “For example, if they run out of their favorite food, they could learn to find something new and thus survive.” He added, “All parrots have relatively large brain sizes compared to most other birds.”

Researchers have previously shown that, when trained, some parrots can recognize and understand objects, colors, and shapes, and even speak with an impressive vocabulary. They can even match five-year-old humans on basic tests of intelligence.

How to Grow Plants in the Classroom

Growing plants in the classroom is an excellent way to get students excited about science!

Start with seeds（种子）in the classroom. 【小题1】 They can do this by putting seeds or beans in wet paper towels and then in a clear plastic bag. The seeds should begin coming out in a few days, which can give the students an idea of what is happening underground when plants begin to grow.

Continue with seeds in the classroom. At the same time as the seeds are beginning to come out, plant the same type of seeds in soil. 【小题2】 They can also predict（预测）how long it will be before the seeds come out and are seen above the soil.

【小题3】 A quick Internet search should let you know which plants are native to your area. This can connect the plant-growing in the classroom with natural history and other social studies lessons. Also, after growing the plants in your   classroom, you can take the students on field trips to see where the plants grow naturally.

Explore the needs of plants. 【小题4】 You can know what they actually need by growing plants in the classroom and making observations along the way.

In all, growing plants in the classroom is sure to be an exciting science lesson. 【小题5】 They can train their creativity with their own gardens!

In 2016, Luncz and her colleagues realized that Brazilian capuchins (卷尾猴) produced stone flakes (小薄片) from the rocks they used to pound (击打) food and dig without necessarily meaning to. It made the team wonder whether the artefacts (人工制品) really reflected any technical planning by those early humans.

Since then, Luncz and her colleagues have been studying tool use in long-tailed macaques (猕猴) on the islands of Phang Nga Bay in Thailand (泰国的攀牙湾). The team set up motion-activated cameras (动作感应摄像头) to study the behaviour of the wild macaques. During 100 hours of footage (镜头)，the team witnessed monkeys accidentally creating flakes as they struck nuts between two stones and then leaving the broken stones to find new, whole stones.

This is almost exactly what the capuchins did in the earlier study. The team then compared 1119 stone flakes from the macaques’ nut-cracking sites with artefacts found at hominin (古人类) sites in Ethiopia, Kenya and Tanzania. The monkeys’ thin, flat, wide stone flakes—ranging from 1.3 to 7.9 centimetres in length—were “almost the same” with flakes that were associated with ancient humans up to 3.3 million years ago, says Tomos Proffitt, another member of the research team at the Max Planck Institute for Evolutionary Anthropology.

The findings could challenge the current understanding of early stone technology, says Proffitt. “I wouldn’t go so far as to say that all of the old material is not intentional,” he says. “But what our study shows is that we can’t be 100 per cent certain that every single flake in the early Stone Age archaeological record was intentionally made. There may be a component within that record that’s unintentional.”