Meet 9 Animals That Don’t Poop

Written by AZ Animals Staff
Published: August 9, 2021
Written by AZ Animals Staff
Published: August 9, 2021

All living organisms must get rid of waste in their bodies, right? Because vertebrates poop, it’s normal for humans to think other animals must poop as well. But some animals don’t do that — there are even some that don’t get rid of waste at all! These creatures have developed alternative means that are unique, shocking, and sometimes even repulsive. Alternately, they may not live long enough to have to poop at all. These animals that don’t poop prove that nature is far more interesting than at first glance.

If you’ve ever wondered how it’s possible to live without pooping, meet 9 animals that will shock you with how their bodies eliminate by-products.

#9 Animals That Don’t Poop: Silkworms

Silkworms feed, defecate, then build cocoons.

Silk moths abandoned a longer adult lifespan in favor of an explosion of reproduction. After a female silk moth lays eggs, silkworms hatch from them as larvae. They then feed on mulberry leaves until they reach the pupa stage, which is when they spin cocoons around themselves. But before doing so, they make a large poop to avoid pooping inside the cocoons. After about two weeks, they emerge as adult moths. Having no mouthparts, they only live for a couple of weeks, with their total lifespan being 6 to 8 weeks long.

#8 Animals That Don’t Poop: Mayflies

With such an abbreviated lifespan, the mayfly doesn’t even possess a digestive system.

Another creature that doesn’t live long, the mayfly lacks a digestive system altogether. Undergoing metamorphosis when it’s born until it reaches adulthood, it hatches from an egg as a nymph, then becomes a merger, has a brief sterile phase as a dun or subimago, and finally becomes a colorful, full-grown adult called a spinner. Since the focus of its life is reproduction, it doesn’t even have a mouth. After mating, males fly off to die and females lay eggs and die from exhaustion.

#7 Animals That Don’t Poop: Butterflies

Butterflies cannot poop because they only drink nectar.

Adult butterflies do not do number two, or even number one, because they drink only nectar. When they excrete it, it comes out as a fine spray of water from the tip of their abdomens or the liquid waste leaves their respiratory systems when they fly. In fact, it can’t even be called urine because it’s almost pure water.

#6 Animals That Don’t Poop: Sponges

Sponges filter water rather than defecating in the traditional manner.

Sponges are ancient, strange creatures that have specialized cells for certain functions but do not have organs or true tissues. Neither can they photosynthesize. Instead, they filter the water they take into their bodies. They excrete a form of “sponge poop” which is carbon that other organisms feed on. This process has a very interesting benefit: Since organic dissolved carbon is inedible to most creatures, sponges consume it for most of their diet without storing it. They accumulate it, convert it to an edible food source, and shed their newly divided cells for other organisms to consume.

#5 Animals That Don’t Poop: Flatworms

Flatworms do not have an anus from which to release poop, so it comes out the same way it goes in — through their mouths.

More than half of all flatworm species are internally parasitic to humans and livestock. Although they have a mouth, pharynx, some amount of intestines, and several sense organs, they lack an anus, respiratory and circulatory systems, and are unsegmented. With no digestive specialization, food goes into the mouth and wastes come out through the same passage.

#4 Animals That Don’t Poop: Demodex mites

Demodex Mites only live for around two weeks, so they store waste without releasing it.

These microscopic mites live in human hair follicles, specifically in the sebaceous and hair follicle glands of the face, in small numbers or individually. These eight-legged organisms are distantly related to spiders. There are two kinds, Demodex folliculorum, and Demodex brevis. In immunocompromised people, they can cause a condition called demodicosis. The symptoms are itch, sensitive skin, redness, and follicular scales along with pigmentation, folliculitis, eczema, papules, and macules. For the rest of us, they’re always there, although they tend to come out at night when we’re asleep. It doesn’t matter how much you scrub your face, either — unless you’ve got an infestation, there’s no point in trying to get rid of them. These tiny creatures do not have anuses at all, since they only live for about 2 weeks. Instead, they have elongated abdomens with large specialized cells to store waste in.

#3 Animals That Don’t Poop: Jellyfish

Jellyfish expel waste through the same hole where they take in food.

Jellyfish are more colorful and fascinating to look at than flatworms, but they are similar in their excretion of waste. Most animals have two holes, one for a mouth and one for an anus. Not so with these mysterious creatures! Instead of digesting things linearly, with specialized cells for taking in a variety of nutrients, jellyfish have a “manus.” And it’s said they don’t throw up or poop, but instead “throop.” Talk about throwing people for a loop!

#2 Animals That Don’t Poop: Tardigrades

Among the most resilient animals, tardigrades have survived exposure to outer space. They also defecate only during their molting phases.

Many tardigrade species only excrete waste when they molt. The alien-looking but somewhat cute “water bears” or “moss piglets” molt four to twelve times during their lifetimes. During the molting phase, their mouths close and they cannot eat while they eject the lining of their foreguts, hindguts, claws, and old cuticles through their buccal openings (mouths). They then excrete the feces of digested lichens and algae through their anuses.

#1 Animals That Don’t Poop: Birds

Birds, such as these hummingbirds, possess a cloaca, which expels both urine and feces.

Birds don’t poop the way mammals do, with separate passages for urine and feces. Instead, they have one passage, called the cloaca, that excretes both urine and feces. Another difference is that mammals excrete the end product urea into their feces, but birds convert urea into uric acid, also known as guanine. That’s why the bird expels a substance that has dark poop in the middle surrounded by white urine. Not all birds pee and poop at the same time, though – ostriches pee through the cloaca before they poop.

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