My husband and I were taking care of Lizzy, our daughter Melanie’s pet dog, on April 17 while Melanie was in the early stages of labour at the hospital. We received a text from our son-in-law, Joe Levanti, that Melanie was about to give birth. Tom and I sprang from our chairs suddenly. It’s a tradition in our immediate family to wait at the hospital for a birth. This would be Melanie and Joe’s first child.

“You take Lizzy out before we leave, and I’ll be waiting for you in the car!” I told Tom. I started the car and waited impatiently. I saw my husband walk out of the front door — but then out shot Lizzy and she was running down the street at great speed.

My husband ran after the dog, and I followed in my car. “Lizzy! Lizzy!” We shouted as fear filled our heart. We chased (追赶) her up and down our Bellwood Avenue. “She’s running onto Wireless Road!” We both screamed with fear. Lizzy dashed back and forth in the busy street. My husband kept up his chase on foot. I shouted to my husband, “Tom! Be careful when you cross the street!”

Within minutes, traffic was actually stopped on Wireless Road. A half-dozen good people got out of their cars to help. Soon, she ran into a safer area and then back to our street. With the help of six strangers, we caught her within a few anxious minutes. Everyone cheered, and we thanked the helpers again and again.

With Lizzy safely back inside, we drove straight to the hospital and were able to see our daughter in the delivery room. My husband and I are forever grateful to the strangers who might have saved Lizzy’s life and who enabled us to be there at the beginning of a precious new one.

When adult humans meet a baby, many can’t help speaking in a higher-pitched (更高音的), sing-song y voice. This shift, known as parentese, is not unique to humans — it has also been observed in animals like monkeys and gorillas. Now, scientists are adding one more species to that list: bottlenose dolphins.

Dolphins are intelligent animals that live and hunt in groups. They communicate in a unique way: every individual produces its own signature sound that acts much like an ID card, usually by its first birthday. But how does each come up with its distinctive whistle? For babies, it might have something to do with listening to Mum. To solve this mystery, researchers examined the sounds mother dolphins, make.

Scientists studied 34 years’ worth of recordings of sounds made by 19 female bottlenose dolphins. When the mother dolphins were near their young, they continued to make their signature sound, but at a higher frequency. They also used a wider range of frequencies than they did when their babies were not nearby.

This discovery suggests that using these modifications mother dolphins assist their young in learning how to produce these calls themselves. Since dolphin babies often spend some years with their mothers before living on their own, it makes sense that this adaptation would help them learn to communicate. At the very least, the higher-pitched whistle likely gets the babies’ attention. “It’s important for a baby to know,’ Oh, Mum’s talking to me now,’” says marine biologist June Mann.

This kind of research could help us understand how language developed in humans. “It is absolutely essential to have basic knowledge about other species and how they communicate,” says Mann. “I would be really interested to see whether dolphins also change their sounds when interacting with babies of others, which is what happens in humans.”

From birds to bees and wolves to frogs, animals use numbers to hunt, find a mate, return to their home, and more—and researchers believe that this ability to process and represent numbers, known as numerical (数字的) competence, influences an animal’s chance of survival.

In a review published in the journal Trends in Ecology and Evolution, Andreas Nieder, a neurobiologist at the University of Tuebingen, Germany, suggests the capability to differentiate numbers has to have a strong survival benefit and reproduction (繁殖) benefit.

Honeybees, for instance, can remember the number of landmarks they pass when searching for food in order to find their way back to the hive (蜂房). Also, for example, male frogs sing “advertisement” calls to attract females. The females, listening for the complexity of their calls, choose the male that sings the most calls.

This can also be seen in animals choosing a larger amount of food over a small amount or in animals forming hunting groups. Wolves are more likely to hunt successfully if they have the right number of wolves in their pack for the size of their prey (猎物): with prey like deer, only around six to eight wolves are needed, while hunting wild ox requires a pack of nine to thirteen. Their prey also use this concept to protect themselves from wolves—deer tend to live in smaller herds, which rarely have encounters with wolves, or gather in large herds to reduce the chance of any individual becoming prey.

Despite these many examples of numerical competence in animals, this subject has not gotten many first-hand studies. “Many of these behavioral findings in the wild have usually been collected as by-products or accidental findings of other research questions,” says Nieder. He argues that more research needs to be done to fully understand the numerical competence.