Why Do Animals Become Extinct?


When we talk about animal extinction, most people think about the extinction event that wiped out the dinosaurs, but there have been many similar events throughout history, some even more catastrophic.

The three main reasons for animals becoming extinct is meteor and comet strikes, climate change, and habitat loss. All of us must play our part to ensure no more species are lost.

What causes animal extinction, and is there a way in modern times that species extinction can be prevented? From meteor strikes and temperature changes to pollution and resource competition, there are many ways in which a species can be lost from the planet.

Why do animals need water?  Find out here

What is Animal Extinction?

The definition of the word “extinction” from the Cambridge English Dictionary is:

A situation in which something no longer exists.

In the Oxford English dictionary, “extinction” is defined as:

The process of a particular thing ceasing to exist.

Animal extinction refers to a time whereby no more of a species exists either in the wild or in captivity. It could mean they are gone from one place but still surviving in another. For example, at the end of the last ice age around 11,000 years ago, a species of ancient horse became extinct in North America, but they continued to thrive in Africa and Eurasia. Those horses are the ancestors of the horses and donkeys that live on Earth today.

There are 20 species of mammals in North America that are currently endangered.  Find out what they are here

Glyptodon is the perfect example of an animal that became extinct in all areas, but a smaller cousin lives today. Glyptodon was basically a giant armadillo with a large, armored shell. It is believed they traveled from South America to North America via the Isthmus of Panama, a stretch of land that joins the two Americas. Glyptodon became extinct 10,000 – 11,000 years ago, at the end of the last ice age.

Top 3 Causes of Animal Extinction

While the most well-known cause of extinction is meteor strikes, many factors can lead to animal extinction. Here are the top 3 causes of animal extinction.

Meteor/Comet Strikes

The most famous meteor impact is the KT event or Cretaceous-Tertiary Extinction Event. This occurred roughly 65 million years ago when a meteor or comet hit the Yucatán Peninsula in Mexico. This caused millions of tons of dust and ash to fill the atmosphere, blocking the sun and causing most vegetation to die off. This caused the eventual starvation of herbivorous dinosaurs, which in turn lead to the demise of the carnivores.

Other meteor or comet strikes have occurred in the past, such as the PT event around 250 million years ago. This extinction event is thought to have been caused by multiple small meteor strikes, as well as other factors such as volcanic activity, and caused the loss of almost 90% of all land animals and approximately 70% of all marine animals.

After the PT extinction event, the planet was a barren, arid wasteland for several million years until the Triassic period’s first dinosaurs began to evolve.

Climate Change

We typically think of climate change with regard to what is happening now, with our oceans getting warmer and summer months getting hotter. However, the end of the last ice age saw huge areas of ice and snow melt as global temperatures warmed. Mastodons, primitive cousins of the mammoth, lived in North America where they adapted to the snowy conditions with thick fur coats. Much of North America was covered by snow and ice sheets and there were several large glaciers. Southern states were slightly warmer with less snow and ice, but temperatures were still very cold.

As the ice age came to an end, mastodons were not able to adapt quickly enough to the warmer environment, and they eventually became extinct around 10,500 years ago. There have been five or six ice ages in Earth’s history. It is believed that as plants evolved and grew to larger sizes, they reduced the carbon dioxide in the air and increased oxygen levels. This meant the summer months were not warm enough to melt the ice sheets.

Carbon dioxide is a greenhouse gas, contributing to rising temperatures. Ice ages tend to come to an end when carbon dioxide levels are high and oxygen levels fall. It is possible that Earth will experience more ice ages in the future.

Habitat Loss

Habitat loss can cause extinction at any time, but the effects tend to be much slower than an asteroid or comet strike. The Vancouver marmot may be a small creature, but habitat loss has put it on the brink of extinction due to climate change. Due to warming temperatures, their alpine habitats are reducing every year. This has a dramatic effect on foraging ranges and breeding patterns, and the survival rates of any future offspring.

The fate of the Vancouver marmot was so dire that in 2003 there were only 30 individuals left in the wild. Thanks to careful breeding programs at Toronto and Vancouver Zoo, the population has grown to around 250, but this is still a serious situation. Further conservation is needed to allow the population to continue growing.

Vancouver Island Marmot

Similarly, the red wolf is also facing extinction if they do not receive help soon. Native to eastern U.S. states, the red wolf loses more of its habitat with each year that passes, and there are believed only to be 50 individuals left.

The main causes of their loss of habitat are human encroachment due to the building of homes and roads, environmental changes caused by rising temperatures, and an increase in competition for resources in an ever-dwindling space. A breeding program was established in 1973 to reintroduce red wolves to areas where they had become locally extinct, but their numbers are still dangerously low.

I have written an article on the evolution of the wolf which you can find here

Can Animal Extinction Be Prevented?

While many causes of extinction are based in nature and beyond our control, we can still take many steps to prevent animal extinctions during our lifetime.

Simple things such as volunteering to pick litter in your local area will make a huge difference to native wildlife. Discarded plastic ends up in our oceans and can be life-threatening to marine life. Birds, fish, turtles, and seals have all been found caught up in plastic from beer cans, milk cartons, and plastic bags. The more we focus on responsible removal of rubbish and recycling plastics, the less ends up in our oceans.

You can also find volunteer placements at rescue centers that care for wild animals caught in poachers’ snares, young animals orphaned due to the loss of their mother, and animals taken in due to habitat loss. Volunteer not only helps the animals at the centers, but you can also help to raise awareness in your local community to prevent the same thing from happening to more animals.

Adopting animals from local zoos, wildlife parks, and charities gives them vital funding to continue their conservation efforts for wild animals. Whether it is to stop poaching, logging, or reducing carbon emissions, adopting animals goes a long way to ensuring these projects can achieve their goals and protect more animals from extinction.

You can do this from your own backyard for local wildlife. Planting nectar-rich or pollen-rich plants will help to provide vital resources for local bees. Without bees, our food supplies would be in serious trouble. Bees and other insects pollinate approximately 70% of the world’s crops, so protecting them is vital to our own future.

Bees and other insects also help to pollinate flowers, which in turn absorb carbon dioxide from the atmosphere and create oxygen. The more flowers, bushes, and trees there are, the better we can reduce the effects of climate change.

Installing a bird feeder or nectar feeder will allow all manner of wild critters to find food, even during the winter months when seeds, nuts, and berries are no longer available. There are hundreds of species of birds native to North America facing extinction due to loss of resources. One bird feeder can provide nourishment for hundreds of animals in your neighborhood.

If you have a birdbath in your garden, make sure to disinfect it once a month as many diseases can be transmitted via stagnant water. Simply empty the water, use a disinfectant to clean the birdbath, rinse it thoroughly, and then add fresh water.

Finally, take care when driving late at night or on rural roads. Many roads cut through natural habitats, meaning animals need to cross roads in order to move through their territory. Unfortunately, wild animals do not have any road sense and often, their flight response causes them to dart in front of traffic.

If you are traveling at speed, the animal you are approaching may not get out of your way in time. Lowering your speed and keeping an eye out for movement along the road’s sides can help prevent accidents.

Unfortunately, many mammals have gone extinct, even in the last 100 years. Find out which animals are no longer around here.

References

American Museum of Natural History. (2019, June 19). What Causes Extinction? Retrieved from American Museum of Natural History: https://www.amnh.org/explore/ology/biodiversity/going-going-gone/what-causes-extinction

D.M.Smith, F., M.May, R., Pellew, R., H.Johnson, T., & R.Walter, K. (1993). How much do we know about the current extinction rate? Trends In Ecology & Extinction, 375-378.

Ebenhard, T. (1995). Conservation breeding as a tool for saving animal species from extinction. Trends In Ecology & Evolution, 438-443.

GC Volunteers. (2018, November 28). 5 primary Causes of Extinction. Retrieved from Preserving Plants and Wildlife: https://gcvolunteers.org/2018/11/28/5-primary-causes-of-extinction/

Gerardo Ceballos, P., Andrés García, P., & Paul R. Ehrlich, P. (2010). The Sixth Extinction Crisis, Loss of Animal Populations and Species. Journal of Cosmology, 1821-1831.

Strauss, B. (2019, October 24). Top 10 Reasons Plants and Animals Go Extinct. Retrieved from ThoughtCo: https://www.thoughtco.com/reasons-animals-go-extinct-3889931

University of WIsconson-Eau Claire. (2015, May 31). Extinction: The Death of Everything. Retrieved from University of WIsconson-Eau Claire: https://people.uwec.edu/jolhm/EH4/Extinction/CausesLink.html

Bryan Harding

Bryan has spent his whole life around animals. While loving all animals, Bryan is especially fond of mammals and has studied and worked with them around the world. Not only does Bryan share his knowledge and experience with our readers, but he also serves as owner, editor, and publisher of North American Nature.

Recent Posts