Natural World
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10 Of The Grossest Egg Sacs You'll Find In Nature

Updated September 23, 2021 1.5k votes 325 voters 26.9k views10 items

List RulesVote up the nastiest egg sacs you least want to find under your toilet seat.

Egg sacs. The very phrase connotes a certain grossness. But they're an important aspect of reproduction for a number of species; animal egg sacs ensure the successful production of future generations for certain spiders, amphibians, and insects. A simple walk in a park or forest during late summer or early fall will provide opportunities to see insects with egg sacs in the wild (given you live in an area with egg-sac producing species, that is). Yet, considering the gag factor many experience with egg sacs, it's understandable you might actively hope not to come across any. 

The various animals, insects, plants, and spiders that produce egg sacs each have a unique ways of doing so. Some sacs are spun with silk. Others have a papery texture. Some are strong; others, such as those produced by frogs, are moist and delicate. Some animals and insects hide or disguise egg sacs in order to protect their growing babies. Some hang them from tree limbs, others place them in water and abandon them. Regardless of the biology involved, the items on this list provide gross egg sac pictures galore.

  • 1

    The Enormous Huntsman Spider Egg Sac Looks Otherworldly

    Video: YouTube

    Huntsman spiders are big suckers, with long, hairy-looking legs. They sit low to the ground, and walk a bit like crabs. After mating, a female huntsman produces an egg sac of silk, with a paper texture, that's flat and oval and contains about 200 eggs. She then hides the sac in a safe place, such as under a rock or beneath loose tree bark. She remains with the sac, guarding it, for three weeks, taking no nourishment.

    Some huntsman moms carry their sacs under their bodies, so they can move about freely. When it's time for the babies to hatch, the mother might tear a hole in the sac to help them out. She then stays with them for several weeks.

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  • 2

    Cockroach Egg Sacs Look Like A Weird Leather Case

    Nobody likes a cockroach (except maybe Renfield), but their egg sacs are worth taking a look at, for their unusual qualities. They resemble a capsule more than a sac, and have a leathery look about them. American cockroach females wait until nearly a week after mating before producing a few egg cases. Each case holds about 15 embryonic cockroaches.

    At first, the mother carries the cases on her abdomen, then finds a safe hiding place for the babies. Cockroaches have sticky saliva, and the female uses hers to "glue" each egg sac to its hiding place. If all goes well, the baby roaches, known as nymphs, hatch from the case in 24 to 38 days.

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  • 3

    Amphibian Egg Sacs Are Definitely Gross

    Female amphibians (frogs, for example) might mate on shore, but they must take to water to lay eggs, which come out in a moist sac. The eggs and their sac have the consistency of jello; if the mother does not quickly cover them with water, they will dry up and die. As they sit in the water, the eggs absorb moisture and swell to many times their original size. When the babies, known as tadpoles, hatch, they are on their own, and often wind up a tender, juicy treat to fish and other aquatic creatures.

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  • 4

    The Repulsive Octopus Stinkhorn Egg Sac

    Video: YouTube

    You'd be forgiven for exclusively associating egg sacs with spiders, but arachnids aren't the only species that produce them. 

    Clathrus Archeri, also known as the phalloid fungus, octopus stinkhorn, and devil's fingers, is a species of fungus indigenous to Australia and New Zealand that also grows in parts of Europe, Asia, and North America as an introduced species. It is one of the rare plants to hatch from an egg sac.

    The devil's fingers gets its nickname from its appearance, which is ferocious once hatched: it unfurls when it grows out of its egg sac, expanding purple-pink "fingers" to reveal a sticky, gooey center. It's a carnivorous plant that subsists on flying insects attracted to the foul stench it omits. 

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