The Dutch primatologist Frans de Waal is and ethologist. It is primate behavior professor in the Department of Psychology at Emory University in Atlanta, USA, and director of the Living Links Center at the Yerkes National Primate Research Center. Waal works mainly with chimpanzees and bonobos and is the author of several books, including "I, primate" and "The Age of Empathy", both published in Brazil.
With primates, such as chimpanzees, it is not uncommon that if a primate in a group dies, the others stop eating for a few days. They are completely silent, look at the body for a long time, try to revive the body. This is typically human
I have an aquarium with piranhas at home. Recently, when one of them died, the other six behaved very strangely. They were exceptionally calm and refused to eat. They were mourning for their mate?
Frans de Waal: I think not. Piranhas also take pieces from each other; I do not think they are very friendly with each other. In general, grief is something unlikely between fish - unless you have individually attached fish, which may be possible in some species.
So why they were behaving so strangely?
There is something called Schreckstoff - is a substance that fish release when they are disturbed. It is possible that your fish just were influenced by what happened to the other fish in a more physiological manner.
What is the difference with the "real" fight?
The typical grief happens to mothers and children in mammals. Usually, you find fight between animals that have individual relationships, not just grew and flew together, but they have friends. All mammals have such ties to some degree, all the birds too, since very often live in pairs. If your partner dies, they are very affected by it.
And if the companion animal belonging to a different species? These stories of dogs that are in mourning when the owner dies would be only an idealization?
No, I think it's a very real thing. This was the case of the dog Hachiko, in Tokyo, Japan. After the owner died, the dog kept going to train with which man usually came for ten years. Whenever you have connections, is between a dog and a human being or a cat and a human being, you can have mourning.
The animals are in mourning as humans do when their companions die?
"Staying in mourning as humans" is a strong statement. They get upset. With primates, such as chimpanzees, it is not uncommon that if a primate in a group dies, the others stop eating for a few days. They are completely silent, look at the body for a long time, try to revive the body. This is typically human - we do not do that anymore, but in times past people did.
Then the hard fight for a few days in animals?
If it is a very important partner as the best friend or the child, then it can last much longer, can last for years. I met a female who lost a puppy for months and half crying for him. It was a very long-term effect.
How do we know that these animals are in mourning? Maybe they just have gone out of your routine because something is missing in your life?
I remember a story in which a baboon mother lost her baby to a predator. Weeks later, she returned to the same area where he had lost his offspring and climbed a tall tree and started calling. This indicates that she remembered what had happened there and what was missing offspring. Primate, we often have the impression that they specifically recall the individual.
Do you think they realize that their mate will never come back?
The only thing about death that primates certainly understand is permanence. That once a person is dead, it does not move more, it is dead. I think they understand that.
How do you know?
I'll tell you a story about it. Some bonobos found a very dangerous snake in the forest and were terrified of it, poking it with sticks. At some point, the alpha female, which is dominant over the male, grabbed the snake by the tail, knocked her to the ground and killed. From that moment, the young bonobos took the snake, the hanged on their necks, walked with her and began to play with her.
This indicates that they know that it is a dangerous animal with which you should be very careful, but once you're dead, you can play with it. So I think they understand that death is a permanent condition.
Monkeys are also aware that they themselves will die one day?
It is difficult for us to know, but there is no indication that they have this kind of understanding.
Other species such as birds, are mourning the same manner as primates?
Some birds stay together for life sometimes stop eating and die if the partner dies. This is true in the case of geese, but also many birds of Passeri order [singing], which have long-term ties.
What animals do you think are the most impressive fight?
I would say elephants because they return the bones of those who lost. If an elephant dies - which at the time, with poaching, often happens - the other elephants inspect the dead animal bones can find them. Not sure, but if anyone has ever done a survey on whether the elephants return to any bones or bones of specific individuals they knew. But my guess is that they return to the bones a bit like us, when we go to a cemetery.
Some animals also bury their dead, digging a grave?
No, they do not dig the grave. It is possible to throw things on their dead in order to cover the body. This seems like a antipredator defense, in the sense that a body smell can attract predators and scavengers. I do not know if they do it systematically.
Dig a grave is a typically human thing, then?
Yes, that's right. Recently, there was the discovery of Homo naledi, a human ancestor. The team said that they buried their dead, which is a true indication of humanity. Even if, in reality, there are a lot of questions about that statement now.
Knowing that animals are grieving can have a positive impact on the preservation?
All we noticed about the animals in terms of their emotional lives or cognition about death help - to make the animals more complex or similar to man and more attractive to people. All this knowledge contributes to the way we see the animals and can change the way we treat animals. It has ethical implications as it were.
