4 Animals Who Can Survive a Year Without Food

Editor’s note: This Care2 favorite was originally posted on July 23, 2017.

As animals who feel hungry several times a day – and aim for three meals daily — it can feel like life revolves around food, for better or worse. But what would it be like to consume one meal a week, a month or even a year?

While humans may never know that feeling — although people have gone without food for many days – it’s amazing to look at a group of animals who do just fine for long periods of time. In fact, every animal on this list can survive without eating — and often drinking — anything for more than a year.

1. Snakes

Crotalus atrox

Western diamondback rattlesnake, Photo credit: Gary Stolz

Snakes have only been around for about 100 million years, but they already comprise about half of all reptile species. This shows how amazingly successful they’ve become at surviving and adapting, despite how some humans feel about them. They are very efficient when it comes to using available resources, and scientists have known for a while that some snake species could survive for up to two years without a meal.

In 2007, a University of Arkansas study investigated the physiological changes that take place when snakes go for a long time without a meal. A group of 62 snakes, including ball pythons, rat snakes and Western diamondback rattlesnakes, didn’t eat for about six months. Amazingly, the animals actually grew.

“Snakes are very evolutionarily successful,” University of Arkansas researcher Marshall McCue said. In this study, the snakes significantly lowered their metabolic rates, some by up to 72 percent. This, it turns out, was the key to their survival.

During that time, the snakes burned up several of their selected fat stores and lowered their metabolic rates in order to survive – all while continuing to grow and thrive.

Snakes, as cold-blooded animals, or ectotherms, gather heat from their environment, and can control their body’s thermostat to a certain degree. Ectotherms don’t need to eat regularly to warm their bodies — and, thus, save an enormous amount of energy that warm-blooded animals cannot.

2. Crocodiles

Nile crocodile

Nile crocodile, Photo credit: Leigh Bedford

In a similar vein to snakes, the crocodiles’ ectotherm status is a huge factor in its long-term survival without food. That isn’t the only thing crocodiles have going for them, though. These animals have outlived the dinosaurs and are the best freshwater predators in the world. On top of that, they have few natural predators, strong jaw muscles that can crush cast iron and can survive injuries like torn off limbs.

As for going without a meal, though, it all comes back to the metabolism. A crocodile’s metabolism is so evolved that its body uses and stores nearly the entirety of the food it consumes. They can regularly go for months without food — and in extreme situations, crocodiles can live off their own tissue for up to three years.

Another interesting fact about crocodile eating habits is that their stomachs are more acidic than any other vertebrate. Thus, they can digest bones, horns and shells. In fact, those pieces act as “gizzard stones” to help grind up coarse food.

3. Lungfish

Lungfish

Lungfish, Photo credit: Nayrb7 

African lungfish can go without food and water for three to five years — in suspended animation, that is. They are ready and prepared so that when water becomes available, they wake up. This adaptation is especially useful in habitats where there is seasonal drought. African and South American lungfish, for instance, burrow themselves into the mud each year and wait for the rain to return.

In suspended animation, animals enter a state of torpor, which is effectively a lighter hibernation. And that slows down their internal clocks until more beneficial conditions appear. Changes in physiology allow lungfish to slow their metabolism to as little as 1/60th of their normal metabolic rate.

Another aspect of maintaining as much energy as possible is, of course, waste management. The lungfish’s protein waste during suspended animation is converted from ammonia to a less toxic urea.

Lungfish can live for a long time, too. One lungfish at the Shedd Aquarium in Chicago was part of a collection from 1933, until it was euthanized in 2017 due to health problems.

4. Olm

Proteus anguinus

Olm, Photo credit: Boštjan Burger

Unlike most amphibians, the olm eats, sleeps and breeds underwater. Delightfully, their existence was first recorded in 1689 by a local naturalist in Slovenia, Valvasor, who reported that olms were washing up from underground waters after heavy rains. Local people believed that they were a cave dragon’s offspring, which led to even more rumors.

Olms have lived in the caves of Slovenia and Croatia for more than 20 million years. These creature are mostly blind, and though they can detect the presence of light, they hunt with other enhanced senses.

The olm’s resistance to long-term starvation is another result of living underground. Since the arrival of food can’t necessarily be counted on, these animals have adapted to eat large amounts of food when available — and then store those nutrients in the liver as large deposits of lipids and glycogen.

That way, when food is scarce, olms can reduce their activity and metabolic rate. In extreme situations, olms can also reabsorb their own tissues. Controlled experiments have shown that an olm can survive up to 10 years without food.

What all of these adaptations come down to, though the methods differ, is the ability to control and slow down the metabolism. But warm-blooded animals, such as humans, lack that ability. Although bears could join this list — with an impressive 100 days without eating or drinking, as well as multiple other animals who hibernate — they can’t come close to shutting down their bodies to maintain such long-term survival in difficult conditions.

Scientists hope to continue studying these animals to understand how we can slow our own body clocks — for medical purposes, as well as the potential for space travel.

Photo credit: MattStone911

208 comments

hELEN h
hELEN hEARFIELD17 days ago

tyfs

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Izorie Irvin
Izorie Irvin1 months ago

Thanks this is very interesting...

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Mia B
Melisa B2 months ago

thanks for posting

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Richard E Cooley
Richard E Cooley2 months ago

Thank you.

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Toni W
Toni W3 months ago

TYFS

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Toni W
Toni W3 months ago

TYFS

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Dubravka T
Dubravka T3 months ago

Never heard that important details. Thank you.

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Vincent T
Vincent T3 months ago

tyfs

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Shae Lee
Shae Lee3 months ago

Thank you for sharing

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Madison I
Madison Idso3 months ago

Amazing animals! Total respect.

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