Our Inner Ape | Frans de Waal

Summary of: Our Inner Ape: A Leading Primatologist Explains Why We Are Who We Are
By: Frans de Waal


Embark on a fascinating journey with ‘Our Inner Ape: A Leading Primatologist Explains Why We Are Who We Are’ by Frans de Waal as we explore the depths of human behavior and morality through the eyes of our closest relatives – chimpanzees and bonobos. Delve into evolutionary logic, with a fresh perspective on our moral reasoning, competitive inclinations, and cooperation. Discover how key behavioral traits among primates, including empathy and fairness, shape our understanding of human nature. This engaging and thought-provoking book offers a unique lens into our own inner struggles and societal challenges, reminding us of the complexities ingrained in our evolutionary history.

Evolution & Morality

The evolution of species and the role of genes in survival was believed to determine an individual’s morality until studies of animals revealed selflessness, sportsmanship, and a sense of fairness in their behavior. Charles Darwin’s groundbreaking work rejected the notion of god creating humans and asserted that all species, including humans, evolved from genetic variations that aided species preservation. This thought was later augmented by Konrad Lorenz, who believed evolution’s purpose was to pass on genes rather than preserving a species. Richard Dawkins coined the term “selfish gene”, which described behavior that benefits others with the same genes. However, Frans de Waal’s study on reconciliation behavior among chimpanzees and other research documented examples of selflessness, sportsmanship, and fairness in various animals’ behavior, proving that morality is not solely dependent on survival of the fittest.

Understanding Bonobos

Bonobos, also known as pygmy chimpanzees, have long hair with a prominent middle part, are more delicate, and have smaller heads than their chimpanzee counterparts. They have been observed to be pansexual and have sex frequently, but not for procreation. Bonobos have also been noted to be more sensitive and nonviolent than chimpanzees, and females call the shots in their societies.

The Power of Group Cohesion in Gender Dominance

Female bonobos exhibit stronger group cohesion, making them the dominant gender, while chimpanzees, who lack such social bonds, are dominated by males.

Experts were initially skeptical of research claims that female bonobos dominated their male counterparts, despite being physically weaker. However, field researchers discovered that female bonobos’ social bonds and group cohesion allowed them to stand up to males, who were less socially united. In contrast, chimpanzees, who live in a less lush habitat separated from bonobos by the Congo River, lack the same social bonds. Female chimpanzees search for food alone and are forced to split up, while male chimpanzees acquire more food through group hunting.

Interestingly, female chimpanzees in zoo settings, where they are in closer proximity to each other, demonstrated a decrease in gender power imbalances. Females formed social bonds and united against aggressive male behavior, even disarming males to prevent retaliation.

Ultimately, the study shows that the dominant gender is not necessarily the physically stronger one, but the one with stronger group cohesion. Female bonobos exhibit this quality, allowing them to dominate males, while chimpanzees, who lack social bonds, are dominated by males.

The Politics of Primates

Chimpanzees establish stable hierarchies through a cycle of cohabitation involving alpha male rule, challenge, and public reconciliation. Frans de Waal witnessed a post-fight embrace between two males and wondered why the winner would make peace with the loser. The answer lies in the importance of cooperation in group hunting. With clear hierarchies, the group can work together. After years of alpha male rule, a challenger emerges, gains supporters through grooming, and a fight ensues until one admits defeat. Among chimpanzees, the defeated male is not driven out or killed but publicly reconciles with the winner. Privileges are granted to the supporters of the winner, establishing a new phase of stable hierarchies.

The Competitive Love Life of Chimpanzees

The power hierarchy among male chimpanzees determines their likelihood of reproducing, with alpha males having more opportunities. Female chimpanzees compete for resources to ensure the survival of their offspring. While female chimpanzees choose to mate with the alpha male, they are selective with other males. Males outside the alpha group must sneak behind the alpha’s back to mate and risk brutal beatings if caught. The ultimate goal is to pass on their genes to future generations.

Gender Differences in Evolution

The physical differences between gender in different species help to draw conclusions about their development over time. In gorillas, males are much larger and more dominant than females, while chimpanzee males are only slightly larger but still dominant. However, bonobo males are only slightly larger than females, and despite male ancestors being dominant, it is the females who hold the power today. This reversal of dominance has also led to differences in life expectancy, with males in dominant positions often having shorter lives due to the stress of constant power struggles. The evolutionary adaptation of gender differences in humans suggests that men were dominant over women at an earlier stage of development.

The Evolution of Testicles

Male primates have varying testicle sizes due to their mating dynamics. Male gorillas have small testicles because the dominant alpha male only mates with the females in his harem, while male chimpanzees have bigger testicles because they share females with lower-ranked males. Male bonobos have the biggest testicles because they mate with multiple females, and their sperm compete to fertilize the eggs. Human testicles are in between in size and suggest that stable heterosexual partnerships have been dominant in human societies for a long time. Overall, testicle size reflects the mating habits of male primates.

Infanticide and Evolution

Eliminating Offspring for Sake of Reproduction.

Infanticide is a shocking animal behavior seen among various species, except for bonobos which are the only primates that do not commit infanticide. Male animals tend to eliminate the offspring of their competitors to mate with females quickly, and this behavior has been observed among bears, rats, dolphins, and all primates except for bonobos. In such cases, female interests tend to clash with those of males. The genes of males that eliminate the offspring of their competitors and rapidly produce their own tend to prevail, while the females tend to safeguard their young ones regardless of the father’s identity.

Bonobos appear to follow the opposite strategy by having sex with all males, including those from other territories. In evolutionary terms, it is pointless for males to kill babies that could potentially be their own. In contrast, human females form pair bonds, and they ensure the paternity of their offspring and receive protection from males. However, the desire to have sex with other attractive partners, which contradicts pair bonding, has not disappeared.

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