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What is the most heartless animal?

Determining which animal is the “most heartless” is not a straightforward endeavor. Ideas about morality and cruelty are human constructs that do not neatly apply to animal behavior and instincts. Animals act to serve their own interests of survival, reproduction, and care for their offspring. They do not consciously make moral calculations about right and wrong. However, some animal behaviors may strike humans as particularly ruthless or cold-blooded. This article will examine some candidates for the “most heartless” animal based on human perspectives on morality.

Animal Behaviors That Seem Heartless to Humans

Some behaviors that seem heartless to human observers include:

  • Infanticide – Killing the young of their own or another species.
  • Cannibalism – Eating members of their own species.
  • Parasitism – Relying on a host species for sustenance to the host’s detriment.
  • Predation – Hunting and killing other animals for food.
  • Abandonment – Deserting ill or injured members of a social group.
  • Deception – Luring prey by faking distress, injury, or interest.

These behaviors generally serve natural functions related to survival or reproduction. However, to human eyes, they may appear cruel, remorseless, or heartless.

Candidate Animals for “Most Heartless”

Based on the above criteria, here are some animals that could be considered among the most heartless from a human perspective:


Chimpanzees are humanity’s closest animal relative, sharing 99% of our DNA. However, they are capable of shocking violence and cruelty toward each other.

  • Groups of chimps wage war over territory, conducting lethal raids on neighboring bands.
  • Chimps will kill the infants of rival groups to eliminate future competitors.
  • Both male and female chimps practice infanticide within their own groups as well to gain resources and mating opportunities.
  • Chimps have been observed eating meat from rivals they have killed or cannibalizing dead infants.

The propensity for cooperative war and the killing of infants who pose no immediate threat seems to go beyond mere survival instinct and has struck some as shockingly heartless.


Dolphins have an exaggerated reputation for being friendly and gentle. But they are predators and have some startlingly cruel behaviors:

  • Dolphins play with their food, tossing, beating, and maiming live prey before killing it.
  • Male dolphins kill porpoises and baby sharks by battering them to death.
  • Dolphins have tried to force themselves on human swimmers.
  • A male dolphin calf died from injuries inflicted by older males who were competing to mate with its mother and were trying to eliminate it as a rival.

The violent play with prey and lethal violence over mating rights seems particularly heartless given dolphins’ intelligence.


While humans admire cats as pets, they are efficient and ruthless predators:

  • Cats play with prey by releasing captured animals and recapturing them repeatedly before killing them.
  • Well-fed pet cats still kill birds and small mammals, suggesting they are motivated by more than hunger.
  • Feral cats are driving numerous bird, mammal, and reptile species to extinction.

Cats are not wantonly cruel, but their play with prey betrays a “heartless” indifference to suffering. Their hunting instinct unchecked by human oversight also has devastating ecological consequences.


Orangutans are highly intelligent apes that share 97% of human DNA. However, they demonstrate chilling violence and what could be deemed cruelty:

  • Both males and females practice infanticide to terminate offspring that are not their own.
  • Some males forcibly copulate with females and are violent toward them during forced matings.
  • Orangutans use sticks to acquire honey but will also use them to “fish” for small mammals that they kill with the sticks.

The violence toward both their own infants and targeted use of sticks as weapons reveals startling cruelty and heartlessness.

Komodo Dragons

The carnivorous Komodo dragon seems to delight in a torturous killing:

  • Their saliva contains both toxic bacteria to infect prey and an anticoagulant to produce hemorrhaging.
  • After biting prey, they will patiently follow it for hours or days as the toxins disable it.
  • Eventually they attack again to eat prey alive, starting with vulnerable soft tissues.
  • They will dig up pregnant deer, first consuming the fetus before killing and eating the mother.

Both the toxins and patient tracking of weakened prey seems to reveal Komodo dragons possess a cruel “heartlessness” and indifference to suffering.


Hyenas have a disturbing reputation for savagery:

  • Spotted hyenas target prey animals’ rectums and disembowel them while alive.
  • Other hyenas eat their prey headfirst, entire skulls crunching in their jaws as victims perish.
  • Hyenas will hunt humans, such as children.
  • Female spotted hyenas are larger and dominant, and will crush the skulls of subordinate male cubs or rip them apart to kill heirs and extend their reign.

The violent cannibalism of cubs and attacks on humans display a frightening heartlessness.


Walruses are not commonly thought of as ruthless, but they have disturbing behaviors:

  • Young walruses are occasionally crushed or suffocated by stampeding adults.
  • Walruses will trample each other to flee danger or gain access to females.
  • Walruses fight viciously over mates, with tusks used as weapons that can cause grave wounds.
  • Walrus groups will steal and kill baby seals.

The opportunistic violence and infanticide seems calculatingly heartless.


Many animals exhibit troubling behaviors that appear cruel, malicious, or heartless from a human moral stance. But animals operate on instinct, not reasoned ethics. They practice violent or lethal behaviors to aid their own survival chances or reproductive success. Judging them by human standards of compassion may not be appropriate or logical. In the natural world, where resources are scarce, reproduction competitive, and predation essential, behaviors evolution has programmed may often seem ruthless but serve necessary ends for those species. No animal can definitively be deemed the “most heartless” across all contexts, as that involves applying human values and morality. Any ranking would be anthropocentric. Nonetheless, the behaviors of species like chimpanzees, dolphins, cats, and hyenas, among others, appear chillingly cruel and remorseless from the standards of human ethics.

Table of Candidate Animals for “Most Heartless”

Animal Concerning Behaviors
Chimpanzees Lethal raiding of rival groups, infanticide, cannibalism
Dolphins Violent play with prey, infanticide
Cats Playing with prey, excessive hunting
Orangutans Infanticide, forced copulation, killing small mammals with weapons
Komodo Dragons Poisonous bacteria and toxins to disable prey, eating alive
Hyenas Disemboweling live prey, cannibalizing cubs
Walruses Trampling and suffocating young, vicious mating combats