Are humans the only animals that kill for pleasure or no purpose?

Question

“Wild animals never kill for sport. Man is the only one to whom the torture and death of his fellow creatures is amusing in itself.” James Anthony Froude (British historian, 1818-1894)

Is this statement factually correct? Have there been any research conducted which help support or disprove this statement?

I did find a few answers via google, but they're mostly from different internet forums and feel insubstantial.

Edit:

After reading the comments, I realized that it's difficult to define precisely what "pleasure" means. So, I'm going to rephrase my question to: "Are humans the only animals that kill for purposes other then food, survival, or other basic necessities?"

If I understand correctly, the quote at the top of this question is assuming that animals kill only for survival (obtaining food, self defense, etc). I would like to know if there are any specific counter-examples where animals do appear to kill for reasons other then survival.

Answer 1

• Dolphins

  From a National Geographic Special on Dolphins:

  "But beneath the harmony lies a darker side of dolphins. Gangs of strong males pick on younger or smaller dolphins. Bottlenose dolphins are even known to kill for reasons other than hunger.

  As a caveat, I was NOT able to find that quote directly from NG online, only other sites quoting it.

• Chimps

  Their reasons for such killings have long been a source of debate among zoologists, but the aftermath of the Ngogo murders reveals an important clue. After the chimps picked off their neighbours, they eventually took over their territory. It seems that chimps kill for land.

  (source: http://blogs.discovermagazine.com/notrocketscience/2010/06/21/chimpanzees-murder-for-land/)

Answer 2

Elephants have been known to murder rhinoceroses, apparently for no better reason that "to test their strength" (although the exact reason isn't known for certain).

The rhino killings stopped, and the case appears closed. But scientists are left to figure out the most baffling question of all: What motivated these elephants to behave in such a savage and uncharacteristic fashion?

The answers they are coming up with would not surprise criminology students in the United States. They also offer no real assurances that the rhinos are out of danger.

In the late 1970s Pilanesberg became a pioneer in the restocking of animals. Baby elephants that would have been marked for slaughter in other parks (as part of the annual cull to keep elephant populations manageable) were moved instead to Pilanesberg along with two adult females to care for them.

Mothers normally drive male elephants from the herd once they reach adulthood. Males start drifting away around age 15, eventually linking up with other groups of male elephants led by a patriarch.

But now that Pilanesberg's elephants are reaching adolescence, there are no adult males for them to follow. Thus, they have become juvenile delinquents deprived of adult supervision or role models.

"There are no adult bulls around to keep them in check," Stuart-Hill said. "So they're highly aggressive and are testing their strength on other animals."

Also:

He prefers a biological explanation: the sudden surge of hormones in adolescent elephants that produces aggressive behavior normally controlled by older males.

If he is right, the killings might have stopped only because the mating season ended. He conceded that three innocent elephants might have been killed and that the problem could resurface next year when the mating season resumes.

The white rhino, hunted to the brink of extinction earlier this century by humans, then would be facing a new threat to its existence from bands of unruly, juvenile-delinquent elephants.

Answer 3

Dogs are said to sometimes kill for "fun":

http://seattletimes.com/html/localnews/2015273676_wilddogs10m.html

A pack of dogs has killed about 100 animals in the past three months in northeastern Washington state while eluding law enforcement and volunteers. ... Authorities are warning residents to take whatever steps are necessary to protect their families and animals because the dogs appear to be killing for fun rather than food. No humans have been attacked, but officers fear that could happen.

http://www.slate.com/articles/news_and_politics/explainer/2009/11/do_wolves_kill_for_sport.html

Dogs are the only animal that definitely kills for sport, but that's only because humans taught them to do so. When a farmer finds a few dead chickens killed during the daylight hours with no missing body parts, the neighbor's dog is almost always the culprit.

Of course, they could be doing this entirely because their innate prey drive tells them to, perhaps to stay in good practice for hunting. So it's difficult to say if it's really just "for fun" or if staying in practice when food is plentiful helps hone their hunting skills for when food is scarce.

Answer 4

Kill for pleasure or no purpose? If you're thinking the animal equivalent Manslaughter (without intent) just imagine an elephant walking to a watering hole and crushing a bug on the way there. Or thinking smaller. Imagine an animal eating fruit of a tree. This might alter the ph balance in it's gut "killing" millions of bacteria in its gut. I remember as a child finding a dead cat beside a cow. The cat had slept next to the cow for warmth and the cow rolled over during the night.

Animal murder (killing with intent, but not for "reasons other than survival")? Think of an animal rubbing it's back or sides against a rock or flicking its tail to rid itself of parasites. Or something like an elephants ear splatting a mosquito. I guess this can be filed under killing for pleasure.

Another case of animal murder for reasons other than survival would be Cecil and Jerico the lions:

ZCTF chairman Johnny Rodrigues said: "The saddest part of all is that now that Cecil is dead, the next lion in the hierarchy, Jericho, will most likely kill all Cecil's cubs."

There's a whole lot of killing out there. Some with intent, most without.