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.

It's 10 o'clock at night, and we've been walking along behind him and his wife, Maria, on the beach in complete darkness for half an hour, hoping that every shadowy form is a green sea turtle that has appeared from the Caribbean to lay her eggs on Tortuguero Beach.

After traveling a long way here to witness the event at the end of the nesting season, we walk behind Castor in dutiful silence, thinking about the impact we could have on a turtle's nesting decision. Although they can't hear well, green sea turtles have a powerful sense of smell. Lights can also disturb them. And if the female feels threatened, she'll likely return to the sea to give up all 100 to 120 of her eggs-a huge sacrifice for an endangered creature.

Earlier that day we read up on threats to the turtles-poisonous waste, plastic bags and fishing hooks among other things. These threats apply, however, only if the baby turtles even make it to the sea in the first place.

"She is there," Castor reports, "making her nest now." A female turtle turns herself around and around in a circle until the top of her shell is nearly even with the sand. Employing her back flippers (鳍肢), she then reaches beneath herself to dig a neat, deep hole for the hundred or more eggs she will lay his evening.

We sit silently on a big piece of driftwood, waiting patiently like family members outside the birthing room. "Come closer!" Castor says, and we bend towards the soft red glow of his flashlight. His right hand holds the massive turtle's left back flipper aside so that the light shines directly into the hole, which is already filled with eggs. Her tail lifts as a soft, slippery egg slides through and goes into the hole, followed by another and another. After laying the eggs, her tail flipper begin to remove sand from the "walls" around her, dragging it over the top of the eggs.

Then Castor signals us to another spot where a nest is hatching (孵化) at the very moment. Dozens of baby turtles desperately move to the surface, trying to drag themselves up out and to the sea. However, a huge driftwood lying in the sand parallel to the sea blocks their passage down the beach. Castor shines his beam toward the water and Maria picks the newborns up and places them on the other side of the wood. If we weren't there at the moment, most of them would have wandered aimlessly toward the jungle and death.

On the way back to the village, I recall my mixed feelings about human impact on the environment, Now I'm home joyous that my presence has helped an entire nest of baby turtles survive the first challenge of their lives.

Sperm whales (抹香鲸) living in the Eastern Mediterranean numbered not more than 200-300 individuals during the past decade. Alarming results from the Pelagos Cetacean Research Institute, conducting systematic observations since 1998, indicate that the population might have been halved to only 100-150 whales. The main threat to this population is the more than 30,000 ships that annually cross their habitat at high speed and the risk of collision with them.

International and regional agreements force Greece to take action to protect the sperm whales, including their habitat, the Hellenic Trench. The pilot system SAvEWhales, which was developed by a team of Greek researchers, contributes to this direction.

SAvEWhales records the clicking sounds of the sperm whales, processes them and sends the data to a land-based analysis center where computer models are used to detect, precisely locate the animals, and finally forward the localization fixes (定位) to nearby ships, all in real time. Specifically developed software combines localization results with shipping information from Marine Traffic, a leading ship tracking service provider, to assess collision risk. If a ship is on a collision course with a whale, its captain can be warned well in advance, so that the ship slows down and/or changes course in time to prevent the collision.

Despite its promise, it may be some time before SAvEWhales, or something like it, can be in permanent use. So far, Emmanuel Skarsoulis, research director of Greece’s Foundation for Research and Technology-Hellas, and his teammates have already identified a few barriers. These include analytical challenges, such as the difficulty of differentiating individual whales when a group is traveling together. Besides, SAVEWhales can’t pick up the location of singing whales like the Mediterranean fin whale which is also endangered.

Still, passive whale detection is relatively inexpensive and can protect at least one of the endangered whale species in the Hellenic Trench.