Why Is Earth’s Surface Not Covered With Poop?

Smelly, dirty, and disgusting may be words that cross our minds when we hear the words “dung”, “poop”, “feces”, “dirt”, or “shit”.

All types of living things on our beloved earth must emit waste substances either in the form of liquid, solid, or gas. One of the biggest producers of feces is animals. Total human and animal feces production in 2014 is estimated to be around 3.9 million tons of feces per year, of which 21% are human feces and the remaining 79% are animal feces. And in 2030 it is estimated that it will touch 4.6 million tons per year, equivalent to around 145 kg of feces per second. If there are so many, why isn’t our earth covered with these feces? Let’s discuss this.

Image Credit: Chad Merda

Dung Beetle

The answer is in this one little animal, it’s dung beetle. Maybe some of us are unfamiliar with his name but certainly familiar with his behavior and we often find it to be one of the characters in cartoons and animated films.

Image Credit: Hidden Kingdoms

Yep, he is the beetle who is often seen rolling feces, but not all dung beets do this. These types of animals are generally able to bury feces up to 250 times their body weight in just 1 night. At present, more than 7000 species of dung beetle are known.

One species of dung beetle, Onthophagus taurus, is able to roll something up to 1141 in body weight. This species is even the strongest animal in the world based on the percentage of the load on body weight.


Daily Dung Beetle Activities

The first thing a dung beetle must do is look for feces. Some dung beetles live on other larger animals, waiting for the animal to pass its feces.

Some others are just hiding and waiting for other animals to take out the dung and then go to the dung when the animal is gone. A pile of elephant feces, for example, can be infested with up to 4000 dung beets in 15 minutes. So when the dung beetle finds the dung, it will immediately process it before the others come.

Simply put, this dung beetle is divided into three groups / types, namely rollers, tunnelers, and settlers.

1. Rollers

Male dung beetle of this type will go to the location of the dung and form the dung into a ball, then drive it with its hind legs. When the female dung beetle jumps to the ball and matches, they will dig a hole together and bring the dung ball into the ground. After that they will breed with the female will lay eggs in the dung ball.

2. Tunnelers

Digger dung beetles have a different way. Dung beetle of this type will approach the location of feces from underground which is by making tunnels. Then he will pull the dung into the artificial underground tunnel.

3. Settlers

Dung beetle settlers have a simpler way, they just lay their eggs in the location of the feces. No need to dig and roll. When the larvae hatch, they will eat the feces around them until they morph into a pupa and then an adult dung beetle.

Image Credit: Duwwel

Other Roles of Dung Beetle

1. Secondary Seed Spreaders

Dung beetle also has another important ecological role. One of them is that they also act as secondary seed spreaders. What does it mean?

For example, feces from monkeys, pigs, and other animals often contain seeds from the fruit they eat. When the dung beetle buries their feces, this dung beetle indirectly protects the seeds from predators and the weather, thereby increasing the chance that the seeds will germinate and grow large.

In some places, this is very helpful. There are even plants in South Africa that have evolved to have seeds that have the shape and smell of dung to fool the dung beetle to bury it. This certainly increases the chances of seeds to grow.

2. Bring Nutrients Near the Root

Another important role is in the agricultural system (livestock farming). Livestock such as cows produce a lot of feces—often we call animal manure—which contains a lot of nutrients. The dung beetle then breaks the stool into small pieces and takes it deep into the ground. This makes the position of nutrients close to the roots of surrounding plants.

3. Fight Global Warming

This little dung beetle even helps us fight global warming by reducing greenhouse gas emissions. Animal feces that lack oxygen make the microbes inside to produce methane, one of the most powerful greenhouse gases. Dung beetles dig and tunnel so that they increase oxygen levels in the feces and prevent microbes there to produce methane.

Conclusion

Dung beetle only performs daily activities, namely collecting feces to be used as food and breeding grounds. However, unconsciously this dung beetle also has another big role, starting from helping hatchery, helping fertilizing, to fighting global warming. The phrase “Not all heroes indeed wear capes” is true, and dung beetle is one of them.

Sources and References:

  1. Why isn’t the world covered in poop? – Ted-Ed
  2. The World’s Strongest Animal Can Lift Staggering Weights – BBC
  3. Berendes, D.M., Yang, P.J., Lai, A. et al. Estimation of Global Recoverable Human and Animal Faecal Biomass. Nat Sustain 1, 679–685 (2018).
  4. Penn, R., Ward, B.J., Strande, L., and Maurer, M. Review of Synthetic Human Faeces and Faecal Sludge for Sanitation and Wastewater Research. Water Research 132. 222-240 (2018).

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