Why are some animals thought of as useless or bad at evolving, and are they really?
There are several species today that are often viewed as “evolutionary failures” due to their odd and often nonsensical evolution. Some people even try to use these odd creatures to prove that evolution is not real, as something surely would not adapt in a way that would lead to its own death or the extinction of the species as a whole. The issue is that these people are focusing far too much on one piece of the puzzle. Due to our relatively short lifespan, it is not possible for us to view the entire history of a species, only a singular snippet in time.
Luckily, humanity has been studying, documenting, and categorizing the information that is available to us for multiple generations, which has provided us with enough information to explain some of these “evolutionary failures”. There appear to be several common factors that result in an organism being viewed as “useless” or “bad at evolution”: specialization, population bottleneck, sexual selection and human interference. In this article we'll explore a couple different creatures from each of these categories so that these scientific concepts feel more real and personal.
Current Species: Koala (Phascolarctos cinereus)
Luckily, humanity has been studying, documenting, and categorizing the information that is available to us for multiple generations, which has provided us with enough information to explain some of these “evolutionary failures”. There appear to be several common factors that result in an organism being viewed as “useless” or “bad at evolution”: specialization, population bottleneck, sexual selection and human interference. In this article we'll explore a couple different creatures from each of these categories so that these scientific concepts feel more real and personal.
Specialization
Current Species: Koala (Phascolarctos cinereus)
A koala’s diet consists almost entirely of eucalyptus leaves, they appear to be incapable of consuming most other plants and will starve if no eucalyptus trees are present. This makes it a specialist species. Specialist species are organisms that require very specific resources in order to survive, typically relating to environment or diet. The issue with specialist species is that a tiny change could potentially result in the extinction of the species. This is why specialist species work best in a stable ecosystem with minimal change. Koalas are the prime example of a specialist species, because not only is their diet centered around eucalyptus leaves; their entire existence is. Koalas have various adaptations that allow them to eat these toxic nutrient-lacking leaves: they have specialized teeth that allow them to both easily remove leaves from the eucalyptus tree as well as grind those leaves up for easier digestion, they produce a special enzyme that assists their liver in breaking down these toxins, and it is also suspected that their incredibly small and relatively smooth brain causes them to use less energy and therefor require less nutrients. However, these adaptations are also their undoing. Due to their “smooth brain” koalas lack recognition skills, to the point where they will not recognize eucalyptus leaves unless they are still attached to the tree. This means if you present a starving koala with a plateful of eucalyptus, the koala will starve to death because it cannot find any food. Now, the koala may seem like a truly useless animal to us, but we must take our human bias into account. We often view intelligence as the key of to success, but this does not hold true for every organism. Koalas have managed to survive as a species for a very long time, and their “evolutionary shortcomings” have nothing to do with the recent decline in their population.
Extinct Species: Haast’s Eagle (Hieraaetus moorei)
Extinct Species: Haast’s Eagle (Hieraaetus moorei)
One specialist species that did succumb to extinction was Haast’s eagle, which went extinct around 1400. This eagle's main prey was moa, so when humans hunted the moa to extinction in the fourteen hundreds, Haast’s eagle went extinct soon after. This is the potential risk that many specialist species face by “putting all their eggs in one basket”.
Current Species: Cheetah (Acinonyx jubatus)
Population Bottleneck
Current Species: Cheetah (Acinonyx jubatus)
In recent years I have noticed quite a few people making memes about how cheetahs are “unstable” in a multitude of ways. They have fertility issues, they are prone to many different diseases, only 50% of cubs make it to adulthood, and they have such bad anxiety they need to be given emotional support dogs in captivity. These numerous disadvantages are not the result of evolution making a mistake, they are the result of a population bottleneck that occurred around 10 thousand years ago. A population bottleneck is an event that drastically lowers the population of a species. This often causes a significant reduction in the gene pool of the species, and often leads to inbreeding. This is why cheetahs have so many genetic issues; severe inbreeding. Since humans do not live long enough to have actively observed the event that nearly killed of cheetahs, it is easy for us to forgot or ignore that it was something that happened.
Extinct Species: N/A
It is hard to find examples of creatures that went extinct due to population bottleneck, because it often is not considered the true cause of an extinction. For example; if climate change killed off most of a species leaving only a small group of closely related individuals, there is a chance they could make a comeback for a while, like cheetahs, or they may fail to reproduce due to the lack of genetic diversity and go extinct within a generation or two. Most people would not consider that an instance of extinction caused by population bottleneck, but an instance of extinction cause by climate change. Due to this, there is a lack of documentation on extinction related to population bottleneck.
Current Species: Babirusa (Babyrousa celebensis)
Extinct Species: N/A
It is hard to find examples of creatures that went extinct due to population bottleneck, because it often is not considered the true cause of an extinction. For example; if climate change killed off most of a species leaving only a small group of closely related individuals, there is a chance they could make a comeback for a while, like cheetahs, or they may fail to reproduce due to the lack of genetic diversity and go extinct within a generation or two. Most people would not consider that an instance of extinction caused by population bottleneck, but an instance of extinction cause by climate change. Due to this, there is a lack of documentation on extinction related to population bottleneck.
Sexual Selection
Current Species: Babirusa (Babyrousa celebensis)
The North Sulawesi babirusa is one of the oldest living members of the pig family. This boar-like mammal is most easily identified by its long tusks that grow backwards in a curve towards the skull on the males of the species. The only flaw with these impressive tusks is that they do not stop growing and often end up penetrating the skull of the babirusa and killing it. These long tusks are also a perfect example of sexual selection. Sexual selection is the competition between individuals of the same sex within a species. This can be seen in many species such as peacocks, elephant seals, and, of course, the babirusa. In the babirusa’s case the females of the species only mate with the males who have the longest tusks, meaning the only genes that get passed on to the offspring are these “long-tusk genes”. While these tusks can eventually result in the death of an individual, the boars typically reach sexual maturity and mate before this happens. While these tusks probably won’t end up causing the species to go extinct, they could prove fatal when combined with other factors. The babirusa is already threatened by illegal hunting, so having the remaining males of the species take themselves out with their own tusks could ultimately result in the extinction of the species.
Extinct Species: Irish Elk (Megaloceros giganteus)
Another example of this is the Irish elk. The Irish elk had the largest know antlers of any deer, approximately 3.65m in length from tip to tip. For many years scientists blamed these antlers for the species extinction, suspecting that they would get tangled in the forest’s trees as they tried to flee from hunters. However, new evidence suggests that there was a decline in antler size before their extinction, mostly likely due to lack of nutrition. Scientists now believe the Irish elk went extinct due to a mixture of starvation and over hunting. This ties into the next factor.
Unsurprisingly, human interference plays a huge role in why so many of these animals are viewed as useless. Every single animal that I have previously mentioned have been impacted by humans in some way. Koalas may be too stupid to eat eucalyptus leaves in captivity, but in the wild they typically aren’t in captivity, so this isn’t really an issue; the koala population has been on the decline in recent years, but only because humans have been clearing trees, resulting in habitat loss. The only reason Haast’s eagle lost its main source of food, the moa, is because humans hunted it to extinction. Cheetahs may have faced a population bottleneck in the past that resulted in some of their issues, but currently they are struggling to cope with the new pressures of hunting, habitat loss, and climate change, which are all a result of human actions. The babirusa is currently threatened by both poaching and habitat loss, despite laws being put in place to protect it. A shift in temperature resulting in the end of the last ice age contributed to the extinction of the Irish elk, however human hunting also played a role in its extinction. There are, unfortunately many, many more example of humans causing animals to become endangered or go extinct, only to label them as somehow defective for not overcoming the challenges we imposed on them.
Current Species: Giant Pandas (Ailuropoda melanoleuca)
Extinct Species: Irish Elk (Megaloceros giganteus)
Another example of this is the Irish elk. The Irish elk had the largest know antlers of any deer, approximately 3.65m in length from tip to tip. For many years scientists blamed these antlers for the species extinction, suspecting that they would get tangled in the forest’s trees as they tried to flee from hunters. However, new evidence suggests that there was a decline in antler size before their extinction, mostly likely due to lack of nutrition. Scientists now believe the Irish elk went extinct due to a mixture of starvation and over hunting. This ties into the next factor.
Human Interference
Unsurprisingly, human interference plays a huge role in why so many of these animals are viewed as useless. Every single animal that I have previously mentioned have been impacted by humans in some way. Koalas may be too stupid to eat eucalyptus leaves in captivity, but in the wild they typically aren’t in captivity, so this isn’t really an issue; the koala population has been on the decline in recent years, but only because humans have been clearing trees, resulting in habitat loss. The only reason Haast’s eagle lost its main source of food, the moa, is because humans hunted it to extinction. Cheetahs may have faced a population bottleneck in the past that resulted in some of their issues, but currently they are struggling to cope with the new pressures of hunting, habitat loss, and climate change, which are all a result of human actions. The babirusa is currently threatened by both poaching and habitat loss, despite laws being put in place to protect it. A shift in temperature resulting in the end of the last ice age contributed to the extinction of the Irish elk, however human hunting also played a role in its extinction. There are, unfortunately many, many more example of humans causing animals to become endangered or go extinct, only to label them as somehow defective for not overcoming the challenges we imposed on them.
Current Species: Giant Pandas (Ailuropoda melanoleuca)
While giant pandas have become well known for their inability/unwillingness to mate no one talks about why they face these issues. Female pandas are only fertile for 24-72 hours a year and are very picky about which males they mate with. This never used to be an issue for pandas because in the wild the females could select a mate from a group of males. Unfortunately, poaching and habitat loss has led to a decrease in panda population, and an increase in isolation. This means pandas will become increasingly inbred, making it even harder for them to reproduce.
Current Species: Kākāpō (Strigopidae habroptilus)
Current Species: Kākāpō (Strigopidae habroptilus)
The kākāpō is a flightless parrot native to New Zealand. When Polynesians first arrived on the island, they began hunting the birds for food as well as their feathers. Later, they brought cats, dogs, rats, and stoats to the island which hastened the decline of the kākāpō population. Many people have pinned the blame on the kākāpō itself for being bad at evading predators, as its response to danger is to “freeze” in place. Fortunately, New Zealand has an intense conservation and recovery program and have increased the population of kākāpō from ~50 to 208 over the span of several decades.
While some of these creatures do suffer from evolutionary shortcomings, the main challenge they face is human interference in the form of poaching, habitat loss, and climate change. I find it incredibly tragic that we have labeled so many of these animals as "stupid", "terrible", or "useless", when in reality we are the ones causing them to struggle and in some cases go extinct. When studying the living things around us it is important to remember that we too are part of the ecosystem and often play a huge role in the survival and wellbeing of these creatures.
Conclusion
While some of these creatures do suffer from evolutionary shortcomings, the main challenge they face is human interference in the form of poaching, habitat loss, and climate change. I find it incredibly tragic that we have labeled so many of these animals as "stupid", "terrible", or "useless", when in reality we are the ones causing them to struggle and in some cases go extinct. When studying the living things around us it is important to remember that we too are part of the ecosystem and often play a huge role in the survival and wellbeing of these creatures.
Sources:
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Chris. “Scientific Scribbles.” Scientific Scribbles, University of Melbourne, 17 Sept. 2017, https://blogs.unimelb.edu.au/sciencecommunication/2017/09/17/koalas-not-the-smartest-tool-in-the-shed/.
Holdaway, R N, and C Jacomb. “Rapid Extinction of the Moas (Aves ... - Science.org.” Science, 24 Mar. 2000, https://www.science.org/doi/10.1126/science.287.5461.2250.
“Irish Elk.” Wikipedia, Wikimedia Foundation, 28 Jan. 2022, https://en.wikipedia.org/wiki/Irish_elk#Extinction.
Karl, B. J., and H. A. Best. “Feral Cats on Stewart Island; Their Foods, and Their Effects on Kakapo.” New Zealand Journal of Zoology, 2012, https://www.tandfonline.com/doi/pdf/10.1080/03014223.1982.10423857?needAccess=true.
Macdonald, Alastair A. “Aberrant Growth of Maxillary Canine Teeth in Male Babirusa (Genus Babyrousa).” Comptes Rendus Biologies, Elsevier Masson SAS, 23 May 2018, https://www.sciencedirect.com/science/article/pii/S1631069118300805.
National Geographic Society. “Cheetahs: On the Brink of Extinction, Again.” National Geographic Society, 23 Aug. 2019, https://www.nationalgeographic.org/article/cheetahs-brink-extinction-again/.
Sample, Ian. “Why Are Giant Pandas so Bad at Mating?” The Guardian, Guardian News and Media, 20 Nov. 2003, https://www.theguardian.com/science/2003/nov/20/thisweekssciencequestions1.
Note: Wikipedia was also used as an information gathering tool to both lead me to more reliable sources, as well as to provide me with the scientific names of the animals used in this article.
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