Buzz
Birth is undoubtedly one of the toughest challenges any living creature will face. From a single cell to a fully developed organism, each species embarks on its unique journey into the world. Despite the shared experience of birth, the ways in which different creatures navigate this process can vary greatly, with many exhibiting remarkably strange life cycles.
This variation should come as no surprise, as the pregnancies crafted by evolution can often appear downright bizarre, even cinematic in their oddity. Here are ten of the most peculiar ways animals make their entrance into the world.
10. Incestuous Cannibalistic Offspring
Adactylidium mites live such a quick-paced life that they emerge from their mother already carrying the next generation. These mites sustain themselves by consuming the egg of a tiny winged insect, the thrips, which measures less than 1 millimeter. This single egg provides all the sustenance the mite needs for her entire lifespan and supplies the energy for raising her offspring.
The life cycle of the mite begins within the mother’s body. Her eggs hatch internally, giving rise to a brood of six to nine females and one male. The larvae then proceed to feast on the mother’s tissue. As they grow into adults, they remain within the exoskeleton of the mother. The male mates with his sisters, fertilizing their eggs. Once the females carry these fertilized eggs, they burst out of their mother’s body, in search of a thrips egg to consume. After fulfilling his role, the male mite dies, having eaten nothing, while the females await the opportunity for their own offspring to feed on them.
9. Egg-Laying Mammals
It’s commonly taught that mammals give birth to live young, yet this fact doesn’t apply to all mammals. The monotremes, a special group of egg-laying mammals, defy this norm. Today, only five species of monotremes remain: the duck-billed platypus and four types of echidna.
Monotreme eggs are typically small with a soft, leathery shell, unlike the hard shells of other eggs. The monotreme incubates the eggs for several days until the young hatch. In the case of echidnas, the baby, known as a puggle, crawls into its mother's pouch. The puggle, compared to other mammals, is tiny and completely helpless upon hatching. For several months, it stays in the pouch, nursing on milk produced by mammary glands located in the skin. When the puggle is sufficiently developed, the mother places it in a burrow and continues to return every few days to feed it until it’s able to survive independently.
8. Mouthbrooding Fish
Fish are not always associated with great parenting skills. In many species, eggs are laid, fertilized, and left to grow without much care. Although some fish defend their eggs and offspring, others, such as mouthbrooders, find it too risky to leave their young unattended. These fish carry their fertilized eggs in their mouths until they hatch and often continue to shelter the young there for a while afterward.
In species like the pearly jawfish, it’s the father that carries the eggs in his mouth. He holds onto them for the entire incubation period, unable to feed himself until the eggs hatch. African cichlids are maternal mouthbrooders, with the mothers going without food for as long as 36 days. After the eggs hatch, the mother allows the young to swim out and feed on their own, but she can call them back into her mouth for safety if danger is detected.
Unfortunately, even this protective strategy is not foolproof. The cuckoo catfish preys on cichlids to force them to spit out their eggs. As the mother cichlid retrieves her eggs, the catfish sneaks in and lays its own among them. The catfish eggs hatch faster than the cichlid's, and the newborn catfish feed on the cichlid eggs, safe inside the mother’s mouth.
7. Gastric Brooding
Sometimes, a mouth is not a safe enough place to carry offspring. For gastric brooding frogs, the eggs were kept safe in the stomach. The mother would typically lay her eggs, but then swallow them. As many as 40 eggs could be ingested, although no more than 20 tadpoles were ever observed to develop inside the mother’s stomach. It’s believed that the stomach acid may have digested some of the eggs. To prevent being digested, the eggs and the hatching tadpoles produced mucus that stopped the production of stomach acid—rendering the mother incapable of eating while carrying her young.
As the tadpoles grew, the mother’s stomach expanded to accommodate them, taking up most of her body space. Her lungs collapsed to make room, and she had to rely on breathing through her skin. After six weeks, she would finally release her fully developed young.
Sadly, both species of gastric brooding frogs went extinct in the 1980s. However, in 2013, scientists made significant strides toward reviving these frogs. By using cloning techniques, they managed to create viable embryos. There’s hope that soon the gastric brooding frog will once again be carrying her young in her stomach.
6. Three Vaginas
Kangaroos, along with several other marsupials, have a female reproductive system that might seem complex at first glance but is essential for rapid reproduction. Instead of a single vagina, kangaroos possess three. Two of these are used to transport sperm to the two uteri, while the middle one is the passage through which the joey enters the world. They have other special adaptations that help them stay almost constantly pregnant.
Once the kangaroo egg cell is fertilized by sperm, it develops for just 33 days before the tiny joey emerges. The joey, blind, pink, and shriveled, must climb through its mother’s fur to reach her pouch and find a teat to nurse. It will stay in the pouch for the next 190 days, feeding until it begins to venture out, returning occasionally to nurse. During this time, the mother can begin the development of another embryo, which will also make its way into the pouch. The mother produces two types of milk—one for the newborn and one for the older joey.
But the process doesn’t end there. The mother kangaroo may become pregnant again even when there is no more room for another young one. Any embryos produced while the newborn is still suckling remain in a state of suspended development within one of the uteri, only beginning to grow when there is a spare teat available.
5. Birth Through A Pseudo-Penis
Female spotted hyenas are not easily spotted in the wild, and it’s not because they are particularly elusive. Instead, their appearance can be misleading, as they possess an appendage that closely resembles an 18-centimeter (7-inch) penis. This is actually a pseudo-penis formed from an elongated clitoris. The female’s pseudo-penis performs many of the functions of a true penis, even getting erections, but it does not deliver sperm. For mating, the female retracts her pseudo-penis, allowing the male to transfer sperm through a channel running through it.
Childbirth for female hyenas can be extremely traumatic, and it’s certainly not something to take lightly. The birth canal is the same structure that forms the pseudo-penis, and a 1.8-kilogram (4 lb) cub must pass through a hole barely 2.5 centimeters (1 inch) wide. First-time mothers face an almost 60-percent chance of the cub getting stuck in the pseudo-penis, which can result in the cub’s death. If the cub remains lodged, it can also be fatal to the mother. The tearing of the pseudo-penis during the birth of the first cub forms scar tissue, which helps ease the passage of subsequent cubs.
Why the female spotted hyena has developed such a complex and painful reproductive structure remains unclear. No researcher has yet provided a satisfactory explanation for the presence of the pseudo-penis.
4. Male Birth
In many species where eggs are carried inside the body, the mother is typically the one who cares for the developing young. However, in species like seahorses, pipefish, and leafy sea dragons, the fathers take on the role of nurturing the eggs until they hatch. These species are known for their elaborate mating rituals, where the male and female engage in extended wriggling and dancing for hours. These synchronized movements help the female accurately deposit her eggs into the male’s pouch before swimming away.
In male seahorses, the fertilized eggs are surrounded by a protective layer of fleshy tissue that ensures proper oxygen and nutrient supply. The male can expand to a size far beyond normal, carrying up to 2,500 developing eggs. Once the young hatch, the male uses muscle contractions to expel them into the ocean. Afterward, he is already prepared for the next batch of eggs and shows no interest in the babies he has just delivered.
3. Darwin’s Monsters
There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae . .
While many find beauty in nature and attribute it to the divine, Charles Darwin could not accept that a benevolent and all-powerful God would have deliberately created parasitic wasps. It was through evolution, he believed, that such effective and ruthless killers were produced.
Parasitic wasps are highly prevalent and prey on a wide variety of invertebrates. Whether spiders, butterflies, or even other parasitic wasps, these creatures hunt their victims down and deposit their eggs inside the still-living hosts. Some wasps paralyze their prey with venom, rendering them immobile while their larvae feed on them. Others specifically target caterpillars, ensuring their larvae benefit from the continued feeding of their hosts. The larvae often secrete chemicals that manipulate the host’s behavior, improving their chances of survival, such as compelling a spider to spin them a cocoon. No matter the host, the conclusion remains the same—something that you would rather not see is about to emerge from your body.
2. Eating Siblings
The bare minimum you might wish for is that survival struggles would wait until after birth. But in nature, the reality is far from that, even within your mother. A sand tiger shark may begin with up to 12 fertilized eggs inside her, but typically, only two will survive. After hatching, the largest baby sharks will kill and consume their siblings in an act known as intrauterine cannibalism. This allows the two remaining sharks, developing in separate uteri, to grow into roughly one-meter-long (3.3 ft) newborns capable of surviving independently. The mother also provides unfertilized eggs for the babies to eat during the nine-month gestation period.
This method of reproduction gives the sand tiger shark the best chance of producing healthy, robust offspring. The mother mates with several males, but by allowing her children to consume each other in the womb, only those with the strongest genetic traits are born.
1. Under The Skin
The Suriname toad (Pipa pipa) is an unusually attentive mother. Preferring to stay hidden in the depths of bodies of water to avoid predators, she ensures that her offspring do not simply swim off before they are fully capable of surviving on their own. When a male Suriname toad is ready to mate, he signals his intentions with a clicking sound created by a bone in his throat. Once a female responds, the male clings to her back for as long as 12 hours while they swim in spiraling circles through the water. This unique dance allows him to fertilize the eggs and secure them against the mother’s back.
Why is it crucial that the eggs stay attached to the mother’s back? Because it is here that they will remain until fully developed. Over time, the mother grows skin over the eggs, encapsulating them within her own flesh. As the young mature, their movements can be seen beneath her skin. The Suriname toad will not allow her babies to emerge as tadpoles. When the young are ready to become toadlets, they will force their way out through the mother’s back, leaving behind large holes as they swim off, now independent and ready to face the world.
