These days, natural is often used as a synonym for good, and for a lot of people, there's nothing more natural than animals. We kind of think they're better than us, uncorrupted by our human ways. But name a human vice or failing, and you'll probably find an animal that shares it—or worse.

1. THE PARENTS CAN BE TERRIBLE ...

Are they eyeing up some pups?

We think of animal mothers as supremely nurturing and use the mama bear as a metaphor for passionate material devotion. But watch out if your cute pet hamster has babies, because she very well might eat them. Babies are fair game for adult animals, and apparently tasty, too. Seagulls frequently kill and even eat chicks—in one study of a herring gull colony, 300 chicks were victims of cannibalism. And you know those charming, cooperative extended families of meerkats? Pregnant females may kill other females' young, and eat them too.

2. ... AND THE KIDS CAN BE HOMICIDAL.

The kids are just as bad, even in utero: pronghorn antelope embryos may grow spikes to kill their womb-mates, and sand tiger shark embryos attack and eat one other. The carnage continues after birth, as hyena cubs and piglets fight with their littermates to the death. And many baby birds push their siblings out of the nest or pummel them till they expire, while those supposedly devoted parents do nothing to stop it. There's even a name for the phenomenon: a bird species with "obligate siblicide" is one where they routinely lay two eggs but the offspring make sure only one makes it to adulthood.

3. THEY CHEAT.

The saltmarsh sparrow knows it takes a village. Image credit: Wolfgang Wander via Wikimedia Commons // CC BY SA 3.0

It's no wonder animal kids are so warped, given the relationships they come out of. DNA analysis has shown that many birds that we admire for "mating for life" have been getting some on the side all along. What scientists delicately call "extra-pair paternity" has been found even in species like geese that are our icons of marital devotion. In the most extreme case found so far, one study of the saltmarsh sparrow found that every clutch of eggs had more than one father, and in a third of the nests, every single chick had a different dad.

But birds at least keep up a facade of fidelity. Less than 3 percent of mammal species even appear to stick with one mate. And it turns out those may be open marriages too. The prairie vole was long thought to be one of the rare monogamous mammals, until DNA analysis showed that almost a quarter of the litters studied weren't fathered by the guy who was raising them.

4. THEY'RE KINKY. (NOT THAT THERE'S ANYTHING WRONG WITH THAT.)

Self-pleasure is common among primates, including the Japanese macaque.

Not only do animals think sex is fine outside of a committed relationship, there's tons of evidence against the idea that they only do it to make babies. Animal kinkiness is common. They masturbate in imaginative ways and use whatever's around as sex toys. Penguins pleasure themselves on tufts of grass, primates with sticks and rocks, and male hummingbirds with leaves caught in spider webs. (Have you ever considered how useful having a tail might be?) And despite what some politicians claim, sex with a member of the same sex is totally natural: it occurs in hundreds of species of mammals and birds.

Animals don't care if their partner is of the same species or a related one. The short-nosed fruit bat can copulate and have oral sex at the same time. This prolongs the action, which has several possible benefits, including increasing the likelihood of fertilization and decreasing the chance of STDs because saliva has antibacterial properties. (Or maybe it's just fun.)

5. SEXUAL VIOLENCE IS COMMON.

Female Rhinella proboscidea need to be wary of male frogs, who may drown them in their violent rush to mate. Image credit: Diogo B. Provete via CalPhotos // CC BY-NC 3.0


What can only be called sexual violence is also found within species, and in animals with the most noble reputations. Male dolphins form gangs and surround a female so she can't get away and take turns mating with her, sometimes for weeks at a time. Research has found that this increases their chance of siring offspring, but that doesn't make it any less disturbing.

In fact, some animals don't even care if their partner is alive. For some, this may have no good explanation other than confusion or depraved pleasure, but for others, it's probably because the end result—reproduction—is the same either way. Male frogs may descend on a female in such numbers that she drowns in the process. But in one species, Rhinella proboscidea, her death doesn't matter. The males squeeze the eggs out of her body and fertilize them.

6. THEY KILL EACH OTHER—AND NOT FOR FOOD.

If they were in the wild, this new mom and baby at Six Flags Animal Discovery Park could be in danger from a male dolphin looking to mate with the mom. Image credit: Getty Images

We like to believe animals only kill when they're hungry, but some of the animals we think are cutest prove otherwise. It's not just frogs that will mate a partner to death: for example, male sea otters will copulate with juvenile harbor seals till they drown—and they sometimes do the same to female sea otters as well. Dolphins batter harbor porpoises to death, and it's been hypothesized that they do it for practice: to get good at killing baby dolphins. Since they breed infrequently and the young take a long time to raise, male dolphins will kill a youngster who isn't their own in order to make a new baby with the mother.

7. THEY DRINK AND DO DRUGS.

Is this one bee in four places, four bees in one place, or have you just had too much fermented sugar?

Using mind-altering substances may seem like the most human of vices, but there's nothing highly evolved about having a taste for drink. Fruit flies will choose alcohol over water and gradually build up a tolerance, wanting stronger and stronger quaff. Bees, those paragons of hard work, are attracted to fermented sugars, and just like us end up bumbling around and flat on their backs. Bees love booze so much they're used in experiments about alcoholism. And one researcher who offered alcohol to a free-ranging captive elephant herd found that they fought among themselves to get at it. When he cut one elephant off, the beast chased down his jeep and attacked him.

Animals do other drugs too. In India, monkeys steal opium from a factory that processes it, and in Australia, wallabies and sheep have developed a taste for getting high by eating poppies. Sometimes we can even blame animals for our own bad habits. It's said that the stimulant effects of khat, popular in Africa and the Middle East, were discovered after people observed that goats get a buzz when they eat it. And did you know why your adorable kitty is so excited by catnip? Partly it's because it has the same effect as a feline sex pheromone. That rolling, rubbing, ecstatic behavior resembles what you'd see in a female in heat.