When animals grow old and are unable to survive, do their offspring take care of them?

If we get old, can’t walk anymore, will the cat we’ve had for ten years carry tea and pour water for us? The answer is obvious—no. It won’t even carry its own food bowl for itself.

So, if we raise a chimpanzee—treat it like a child from the start—when it grows up and you’re old, will it take care of you the way human children do? This is a question scientists have actually studied. The answer may surprise you.

Some people say, how come animals don’t know to take care of their parents? “Ravens feed back,” “lambs kneel to nurse,” and these two idioms are ones we’ve all heard since childhood. When we were kids, our teachers told us that when a lamb kneels while nursing, it’s showing gratitude to its mother; when a raven grows up, it carries food to feed its elderly mother. It sounds so moving. But the truth may be nothing like what we think.

“Lambs kneel to nurse” is really just a matter of posture. A mother sheep’s nursing organs are located in the abdomen toward the back; a lamb’s neck isn’t long enough. It bends its front legs and kneels so its mouth can reach just right. It’s the same as you bending over to eat—not because you’re grateful to the table, but because you can’t reach it.

“Ravens feed back” is the same, too. To this day, no scientific paper has been able to prove that ravens have the habit of feeding their parents in return. Ancient people probably mistook the behavior of young ravens helping to feed their younger siblings as “children feeding their parents.”

Of course, we don’t need to deny the moral of these idioms. They convey the virtue of “gratitude,” and that’s a good thing. But from a scientific perspective, they are indeed not real animal behaviors. So, in the real animal world, do children really ever “support the elderly”?

If primates don’t have this kind of behavior, then other animals are even less likely—so let’s start with our closest relatives: chimpanzees.

In 2022, a study published in the journal Science Reports documented a rare case within a chimpanzee community: an elderly chimpanzee named “Jenny” had severely worn teeth and had difficulty chewing. After her adult daughter “Milly” discovered it, she would proactively chew tough food for her mother ahead of time, then feed it to her to eat.

It’s almost exactly the same as how human children take care of elderly parents.

Even earlier, zoologists in the Mahale Mountains of Tanzania also captured similar scenes. An elderly chimpanzee who had once been the leader of the group no longer had teeth—its teeth had fallen out—and it moved slowly. But it was still allowed to remain in the group, and younger individuals provided it with food and protection.

The researchers also found that although elderly chimpanzees have declining physical strength, their foraging experience is extremely rich. During the dry season, when young chimpanzees can’t find food, the older chimpanzees lead them to water sources and edible plants. This “value of experience” keeps them respected within the group.

A British primatologist, Jane Goodall, also recorded an even more touching case: an elderly chimpanzee named “Greybeard” who was blind in both eyes. Not only did its adult offspring guide it, they also helped drive away competitors that invaded its territory.

So chimpanzees really do “take care of” elderly parents.

The social structure of golden snub-nosed monkeys is very special. In one group, it usually consists of one adult male, multiple females, and their offspring. Scientists have found that among female golden snub-nosed monkeys, there is a kind of “aunt behavior”—female monkeys vie with one another to care for other people’s children.

Researchers observed at the Chengdu Zoo that when a baby monkey is held by its mother, the nearby “aunts” will proactively move closer, doing everything they can to “snatch” the baby monkey away and hold it themselves. The mother of the baby that gets “snatched” is not anxious either; she takes the opportunity to eat and replenish nutrition.

Clearly, if this behavior appears in the golden snub-nosed monkey family, it must have its benefits. First, “aunts” can accumulate childcare experience by caring for other people’s children, preparing for when they become mothers themselves. Second, when the mother frees up time to forage, she can provide the child with more abundant milk. Finally, with care from more “aunts,” the baby monkey can learn social skills better.

This cooperative rearing model provides rich ground for golden snub-nosed monkeys’ “aging support.” Because in this group, it’s not a case of “raise them and then they disperse,” but rather long-term close connections are maintained. Although there are currently no observed exact cases of golden snub-nosed monkeys “supporting” elderly parents, this cooperative rearing social structure provides a foundation for intergenerational assistance.

In other words, if a group can’t even manage “helping others take care of children,” then “supporting the elderly” becomes even more impossible.

There’s also an even more interesting study. French scientists at the University of Rennes observed behaviors in a group of black-tailed lemurs (capped tail monkeys) and found a phenomenon: older monkeys have “the floor” within the group.

The researchers recorded situations in which 9 female monkeys called more than 800 times, and found that when monkeys aged 7 or older called, 75% of the other monkeys would respond; whereas when monkeys under 2 years old called, only 40% of the monkeys paid attention.

Moreover, the researchers found that this phenomenon has nothing to do with the monkeys’ level of power, social status, or whether they have children; the only factor related is—age.

The research team also observed that when older monkeys “spoke,” the other monkeys would stop what they were doing,认真“listen,” just like polite humans. Although older monkeys don’t talk much, once they do, they always get a response from the younger monkeys.

The research team believes this indicates that “respecting elders” may have a biological basis, a kind of instinct deeply rooted in the evolutionary process of primates.

Of course, “respect” doesn’t equal “support.” But respecting elders is the first step toward supporting them. Without respect, there’s no care afterward.

Besides primates, almost no other animals show this kind of behavior, because most animals don’t even know who their “parents” are, for example fish, reptiles, and most insects. They belong to a “abandonment-type” life strategy: once they lay eggs, they leave, and the offspring fend for themselves. After baby sea turtles hatch, they crawl toward the ocean on their own, and they may never see their parents in their lifetime; the “mother” that tadpoles find is most likely just an unfamiliar frog.

Second, most animals get driven out of the home by their parents. Most mammals and birds follow a “tutelage/raising-type” pattern—parents raise the young until they can live independently. But once the young become adults, the parents will drive them away without hesitation.

This survival pattern exists because resources are limited. There’s only so much food in a territory. If the offspring don’t leave, they’ll compete with their parents for food. Nobody will be full enough, and nobody will live well.

Even some primates are like this. For example, gibbons are a typical case. Once a young gibbon enters the subadult stage, its parents will drive it out of the home, forcing it to independently find a space to survive and build its own family.

Third, most animals simply don’t live long enough to grow old. This is the most truthful point. In nature, dying of old age is actually a luxury. Research shows that animals living in well-managed zoos typically have average lifespans that are usually twice as long—or even longer—than their counterparts in the wild. In the wild, most animals don’t even reach the “aging” stage before being eaten by predators, being killed after being outmaneuvered during hunting because they’re too old, being killed by disease, being robbed of life by starvation, and so on.

Very few animals have the chance to enter the aging stage. That means most animals have already ended their fight before they even reach the step where they would need care from their children. However, it seems there may be one exception here—lions. As the only social species in the cat family, they appear to have behaviors in which offspring care for their offspring and later generations.

Someone might say: don’t lion prides have “feed-back” behavior? When a lioness is elderly, her daughters help tear open the skin of prey so she can eat the meat. This observation is correct, but it needs an additional clarification.

In a lion pride, males are driven away, but females remain in the group. When the mother becomes old and her teeth deteriorate, after a young female lioness succeeds at hunting, she indeed helps the mother tear open the fur of the prey so the old mother can eat the meat.

But there’s a crucial premise: food is abundant. If the lion pride is in a situation of food shortage, the elderly lioness will leave on her own and walk toward death. No daughter will try to keep her or take care of her. Because in the harsh rules of nature, the old, weak, sick, and disabled slow down the survival of the entire group. And male lions are even worse off: when they reach old age, they will be challenged by younger wandering male lions; after losing, they leave with injuries all over their bodies, and in the end they become thin and bony, with no choice but to fend for themselves and die.

This is the truth of nature: family ties depend on conditions.

In summary, among all animals, it’s not only humans that show behavior of caring for elderly parents. On the contrary, chimpanzees take care of elderly parents; caped tail monkeys “respect” older elders; golden snub-nosed monkeys help take care of other people’s children. Among primates, there truly exists a kind of “respect for the elderly” and “mutual help,” to some extent.

But it’s not because they have a concept of “filial piety.” It’s because over the long course of evolution, groups that know how to help each other and take care of one another live longer and spread farther. And in fact, the vast majority of animals don’t have this behavior or concept—which is also their survival rule.