Buzz
Nature has birthed some truly remarkable survivors. Cockroaches that keep going even after their heads are severed, bacteria thriving near Earth's molten core, and tardigrades enduring nearly anything. But for every evolutionary triumph, there is a counterpart—a clumsy, sluggish, peculiar creature that somehow escaped natural selection’s attention to persist in its puzzling existence.
From animals with bizarre eating habits to those that willingly become prey, and even those that refuse to reproduce, the animal kingdom has no shortage of evolutionary flops. This list highlights ten of the most notorious failures, ten animals with no discernible survival instincts.
10. Babirusas
There are many reasons an animal might have tusks: for defense, hunting, digging, or mating displays. But for babirusas, the most tragic use of tusks is that they primarily serve to kill the animal itself, slowly and agonizingly.
Babirusas are a species of wild pigs known for having two sets of tusks, with the male babirusas' tusks growing to extraordinary lengths. The upper pair continue to grow throughout their lives, curving backward and downward until they pierce the pig’s skull. In an absurd twist of evolution, these pigs have developed tusks that grow down through their own heads, puncturing their brains, making their survival strategy highly questionable.
9. Some Miserable, Infected Rats
While mice and rats might typically boast some of the sharpest survival instincts in the animal world—just ask anyone who's tried to rid their home of them—they fall victim to one particular parasite that essentially erases their survival knowledge.
Introducing, the zombie rats.
The parasite Toxoplasma gondii mainly targets cats, but it has a bizarre, mind-altering effect on rodents. When cats excrete the protozoa in their feces, mice and rats often ingest it and become infected. Once inside, T. gondii manipulates their genetic makeup, eliminating their instinctive fear of cat smells—especially urine—turning them into easy prey for cats, thereby completing the parasite's cycle with a new, well-fed host.
8. Steller’s Sea Cow
The mammalian order Sirenia currently includes just two nearly indistinguishable species: manatees and dugongs. However, back in 1768, this group had another member: the massive, 30-foot-long Steller’s Sea Cow, a giant version of the dugong. Despite manatees being slow, clumsy, and overly trusting, the Steller’s Sea Cow was even worse, contributing to its rapid extinction.
The Steller’s Sea Cow vanished within just 27 years of being discovered by humans. While our ancestors bear most of the responsibility, the animal itself played a significant role. Stretching 30 feet, it was essentially a giant mass of blubber with no instinct to protect itself. Friendly and unafraid of boats, much like modern-day manatees, it became an easy target for hunters, resulting in its swift extinction after just 27 years of interaction with humans.
Sad face.
7. Cheetahs
Sadly, due to habitat destruction and human competition, cheetah numbers have dwindled to just a few thousand individuals scattered across a tiny fraction of their once vast range. This has led to a significant reduction in the cheetah gene pool, creating what can only be described as a genetic puddle. Modern cheetahs are heavily inbred, resulting in poor health and low reproductive success. To make things even worse, these cheetahs actively resist any attempts by scientists to help save them.
To try and save the species, scientists have been genotyping captive cheetahs to identify the least related individuals for breeding purposes. The issue, however, is that cheetahs, no matter how unrelated they are, struggle to reproduce. Breeding attempts fail more often than they succeed, mainly because female cheetahs have irregular ovulation cycles, and all captive cheetahs are so stressed that they can’t mate properly.
It’s a bit comical to think of cheetahs in this light. We’re so used to seeing them sprinting at lightning-fast speeds, hunting down their prey like apex predators. Yet, the cheetah is a stark reminder of the devastating impact humans can have on even the most formidable predators.
6. Kakapos
If you’ve never heard of a kakapo, that’s understandable. Only about 200 of these owl parrots are alive today, and they can only be found on two small islands off the coast of New Zealand. The reason for their lack of success—besides human interference—is that kakapos are simply too sweet, too naive, and far too defenseless.
The primary defense strategy of the kakapo is to remain completely still, hoping their green feathers will make them invisible. Unfortunately, this approach proved ineffective when they encountered humans and their hunting dogs. Additionally, they are painfully slow to reproduce and are often prone to mating with non-kakapos. Any object even vaguely resembling their size and shape—especially if it’s round—is fair game for the confused male kakapos, much to the dismay of the few remaining females.
5. Hymenopterans
Hymenoptera is the insect order that encompasses ants, bees, and wasps. This order has produced countless billions of individuals, all born to be expendable workers with short lives.
Hymenoptera is home to the most examples of eusociality—the complex, caste-based colony structures found in ants and bees. These societies divide members into reproducing queens (and other related roles) and non-reproducing workers. Workers have no chance of reproduction and exist solely to support the reproductive caste, perform menial tasks, and die young.
Though all colony members are intensely devoted to the survival of the chosen few, the vast majority of them have little concern for their own survival.
4. Pandas
But honestly: how could you leave panda bears off a list of the most self-destructive animals? These goofy bears don’t have much going for them when it comes to survival skills.
Pandas evolved from more carnivorous bears, so their digestive systems are ill-equipped for a bamboo-only diet. This forces them to spend most of their time eating and digesting, usually sitting down to conserve energy. Along with their sedentary habits, pandas are notorious for being terrible at breeding.
The odds of any two pandas both being interested in mating are astronomically low, and even when they are convinced to mate, panda mothers have a strange tendency to randomly kill their newborn cubs. Some animals simply don’t seem to want to survive.
3. Killdeer
Killdeer are a type of wading bird found in North and South America. They claim the top spot on this list for a shockingly simple reason: adult killdeer are almost constantly trying to end their own lives.
At least there’s a reason behind the suicidal behavior of killdeer. It’s driven by the parents’ desire to protect their offspring. That said, the end result is still just as deadly.
One tactic that mother killdeer use when they see a predator is called the “broken-wing display.” The mother pretends to have a broken wing in an effort to lure the predator away from her chicks, often sacrificing herself in the process. Another tactic they use is the “ungulate display,” where the bird lowers its head and charges at predators, which usually results in… well, one dead killdeer.
2. Sloths
You saw this one coming. Sloths are so terrible at surviving that they were named after one of the Seven Deadly Sins. Imagine knowing someone named Gluttony—you’d be pretty sure they weren’t exactly thriving in life. But sloths don’t make this list just for being slow, dirty, or taking forever to cross the road. No, sloths made it here because of their bizarre bathroom habits.
For reasons still baffling ecologists, sloths don’t simply drop their waste from the treetops as most tree-dwelling creatures do. Instead, they make a slow journey to the forest floor, dig a small hole, relieve themselves, and cover it up—albeit not very well. This drawn-out process makes them vulnerable to falls and predators. Unsurprisingly, sloths are often targeted by other animals during their risky bathroom trips, marking them as instinctual failures.
1. Octopuses
Unlike many other species on this list, octopuses (not octopi) have a lot of strengths; they are some of the most intelligent creatures on Earth, capable of regenerating limbs and blending in with their surroundings. However, the real issue lies in their reproductive cycle, which might be one of the most disastrous in nature.
Male octopuses use one of their arms as a makeshift reproductive organ, inserting sperm into the female’s siphon—the same opening used for water expulsion and movement. This leaves the female in a vulnerable position, and after the male’s self-destructive act, he dies, overwhelmed by his own biological urges. The female, in turn, succumbs to her own demise, starving to death after laying her eggs. Octopuses may be deeply committed to reproduction, but they have truly disastrous survival instincts.
