Does eating apex predators carry health risks

An apex predator is a carnivorous animal that has no natural predators of their own and is top of the food chain in their environment. Despite having no natural predator even apex predators have one organism to fear, Humans as humans in some ways are the apex predator of the planet (though there is some debate whether humans are actually apex predators). Humans have hunted most species of animals across the planet for thousands of years as such even top predators have reason to fear us. However just because humans are able to hunt and eat most every species it does not mean there may be drawbacks to doing so such as potential health problems linked to the contents of an animal’s meat. Since apex predators are at the top of a food chain their bodies may accumulate potentially toxic material in their body from the animals that they prey to a dangerous degree that they themselves may have a natural resistance to.

Polar Bears: Ursus maritimus

Polar bears are a hyper carnivorous species of bear found within the artic circle where they will feed on various seals species, fish and birds. It has long been known by artic travellers and Innuits that eating of polar bear livers can cause severe illness. Polar bears can cause ill effects after around 2 hours after consumption, with symptoms including headaches, drowsiness, irritability and sluggishness as well as pealing of the skin. The main theory for this phenomenon is that polar bear livers contain high concentrations of vitamin A which may be at toxic concentrations to humans. This is because excessive amounts of vitamin A can lead to development of hypervitaminosis which can be fatal (Rodahl. K, Moore. T, 1942). This excess of vitamin A may be caused by the high level of fatty tissue in their liver which vitamin A binds to due to being highly fat soluble.

Sharks: Selachimorpha

Sharks are species of cartilaginous fish which are found in oceans across the earth, which have thought to have evolved around 380 million years ago. Sharks are universally carnivores in one form or another (though very few sharks can be considered man eaters) most shark species are considered apex predators in their own right. Many countries fish sharks for food with Asia being a major component in the global shark meat trade. There are numerous public health benefits to eating fish over land animals including reduced risk of cardiovascular disease and osteoporosis. However various toxins can accumulate in marine life including heavy metals such as mercury, arsenic, copper, selenium, lead and cadmium. Since sharks are an apex in marine environments, they represent a higher risk of bioaccumulation of such toxins. One particularly bad heavy metal is methylmercury (MeHg) which has a 90% absorption rate in the human body and can lead to atrophy of the cerebral cortex ataxia and increased risk of cardiovascular disease. Some studies show that as a result of this bioaccumulation that shark meat is not safe to be used as a food source (Wha Kim. S, et al, 2019).

Wolves: Canis lupus

A wolf is a large species of social canine found across North America and Eurasia; they will live in packs of around 7 animals. Wolves a highly carnivorous and will hunt numerous larger mammals as well as smaller mammals. Wolves are the direct ancestors of domestic dogs as well as having several known subspecies which they can produce fertile offspring with. Much like polar bears wolves and dogs accumulate vitamin A in their liver which can become toxic levels. While wolf liver is not initially as toxic as polar bears and can be consumed. The older the animal is the more vitamin A the liver will accumulate and thus the more toxic it will become. A diet that can include canine livers can lead to headaches blurred vision and seizures.

Big Cats

There are numerous big cat species alive today across the globe including lions, tigers, jaguars and lynxes many of whom can be considered apex predators. Cat species are ultra carnivores hunting numerous other animal species within their environment and can range from group hunters such as lions to solitary like tigers. Any big cat species are not commonly eaten by humans though there is no documented health problems linked with eating big cat meat. Many big cat species such as lions and tigers are critically endangered leading to numerous prohibitions on hunting them. Big cats may also carry less risk than animals such as domestic cats who are considered an intermediate host for toxoplasmosis. Big cats my be an instance of a animal that isn’t commonly eaten and would not have any negative ramifications.

Snakes and crocodiles

Various species of snakes and crocodilians can be considered apex predators within their native eco systems and are only preyed upon by humans. Various snakes and crocodiles are farmed and caught for meat consumption with this comes numerous biological risks including salmonella bacteria as well as other bacterial cultures. Systematic fungal diseases are common amongst captive reptiles though this is mostly skin based and not seen as an overt risk to humans. Sparganosis and Pentastomiasis can be contracted from snake meat and trichiniasis can be contracted from monitor lizards and possibly crocodiles. However, most of the health risks come from infection from pathogens the reptile species may be harbouring. This is not intrinsic from the animals themselves and may be avoided through more sanitary farming conditions. The risks associated with eating wild reptile specimens is the same as eating any wild animals such as eating roadkill (Magnino. S, et al, 2009). From this it can be inferred that crocodiles and snakes are not inherently dangerous to eat as apex predators as the risks associated with them can be found in any wild animal even those who are not apex predators.

Giant Pacific Octopus: Enteroctopus dofleini, Atlantic Giant Squid: Architeuthis dux

The Giant pacific octopus is a species of large cephalopod native to the northern region of the Pacific Ocean including eastern Asia and the western coast of North America. It feeds on various fish, scallops, crabs and shrimp and may even scavenge bird carcasses. While the Atlantic Giant squid is native to the Atlantic Ocean mostly in deep ocean environments. They will feed on various deep-water fish as well as other squids. Cadmium in certain concentrations can be considered toxic to humans due to the element’s long half-life and links to lung cancer in humans. Cephalopods such as squids and octopi are seen as large sources of accumulated cadmium in human diets especially in Asian countries. As such this bioaccumulation can be seen as a high risk to human health through its consumption. Studies show that cadmium accumulates the most in the digestive glands implying it is the result of the animal’s diet. Concentrations can vary in species depending on diet and feeding ranges though is particularly in species that feed on other cephalopods (Storelli. M. M, et al, 2005). However, this cadmium builds up while more prominent in more apex predatory cephalopods it is still a problem amongst all cephalopods species and as such will carry a similar level of risks to human consumers. However, many of the problems with eating octopus from bioaccumulation of pollutants in the water supply meaning if not for heavy pollution of oceans cephalopods may be safer for consumption. Many studies show correlations between levels of pollutants in marine environments and the saturations in the tissues of aquatic life (Mshana. J. G, Sekadende. B, 2014).

Swordfish: Xiphias gladius

This is a species of large migratory predatory fish found in the Atlantic Ocean, they are known for their long extended upper jawbone (Sword). Swordfish are members of the tuna family and are considered an apex predator of pelagic ecosystems. Due to their position on their food chain, they have a tendency to accumulate high levels of mercury in their muscle tissue. Swordfish may accumulate mercury more so than other predators in a similar environment. As well as this there if a higher concentration in larger swordfish specimens. This accumulation is thought to be caused by biomagnification in marine food chains as many see mercury levels as an indicator of ecosystem health. This is both on a temporal and spatial scales for marine ecosystems, most studies on mercury levels in swordfish comes from the Atlantic Ocean with other oceans reaping smaller data sets. The world health organisation has set strict regulations on what is considered safe levels of mercury (Chen. M. H, et al, 2007).

Spotted hyena: Crocuta Crocuta

The spotted hyena is a species of hyena found in sub–Saharan Africa where they live of a highly carnivorous diet, unlike other species of hyena the spotted hyenas is more of a hunter than a scavenger. They live large complex social groups which are led by competing dominant females which provide for their own pups only. While there is no biological evidence that hyena meat is dangerous to humans and in some parts of Africa their meat is eaten. There is however some scripture that prohibits eating hyena meat though this is due to perceived supernatural elements hyenas where thought to possess. Though this has no real grounding or evidence that hyena meat has any negative affects on humans there are groups of people that will not eat it because of perceived side effects (Pendergraft. M, 1992).

Whales: Cetacea

Whales are large aquatic mammals which are found in oceans across the world, they are for the most part filter feeders eating large amounts of plankton and krill. Though whales like orcas are considered true apex predators hunting sharks, fish and even other whales. Other species of whale can be considered apex predators such as the blue whale by virtue of being too large to be preyed upon (with the exception of pups being targeted by orcas). Polyfluoroalkyl compounds (PFC) have been shown to have numerous side affects including developmental, reproductive genotoxic and carcinogenic disorders in animals. Due to low biodegradation PFCs are considered persistent marine pollutants and can be transferred to humans through marine mammals and other marine life. Due to whales consuming large amounts of biomass in marine environments they can suffer high levels of bioaccumulation of PFCs leading to their meat containing high levels of them. Dietary intake of whale meat can cause exposure to these marine pollutants in Danish populations (Weihe. P, et al, 2008). One problem is that these pollutants do not occur naturally and are a result of human industry and would not be a problem in whale meat if not for this. However, whales being so high in the food chain would still pose a much larger risk to human consumers.

Conclusions

From the examples above it seems that bioaccumulations are the main cause for risks associated with eating apex predators. Animals at the top of their food chains will logically accumulate substances found within animals within an ecosystem both good and bad. And so, it is logical that potentially harmful substances will become concentrated in apex predators. However, this isn’t universal amongst these predators’ big cats and spotted hyenas for the most part don’t suffer from any kind of bioaccumulation. In addition to this, other animals discussed here that carry risks eating mostly come from pathogens which could be found in equal concentrations elsewhere. Another point is that a lot of the bioaccumulation is of substances that are introduced into the respective ecosystems through human pollution. It can therefore be argued that in these cases the animal would be otherwise safe to eat. As a final point it seems that there is no hard rule that an animal’s status as a apex predator automatically makes dangerous for humans to eat.

References

Chen. M. H, Chen. C. Y, Chang. S. K, Huang. S. W, 2007. Total and organic mercury concentrations in the white muscles of swordfish (Xiphias gladius) from India and Atlantic oceans. Food additives and Contaminants volume 24 (9). 969-975.

Pendergraft. M, 1992. “Thou shalt not eat the hyena”. A note on “Barnabas” epistle 10.7. Vigiliae christianae volume 46 (1). 75-79.

Rodahl. K, Moore. T, 1942. The vitamin A content and toxicity of bear and seal liver. Biochemical journal volume 37 (2). 166-168.

Magnino. S, et al, 2009. Biological risks associated with consumption of reptile products. International journal of food microbiology 134. 163-175.

Mshana. J. G, Sekadende. B, 2014. Assessment of heavy metal pollution in octopus Cyanea in the coastal water of Tanzania. Journal of health and pollution volume 4 (6).

Storelli. M. M, Barone. G, Marcotrigiano. G. O, 2005. Cadmium in Cephalopod Molluscs: implications for public health. Journal of food protection volume 68 (3). 577-580.

Wha Kim. S, et al, 2019. Heavy metal accumulation in and food safety of shark meat from Jeju Island, Republic of Korea. PLoS ONE volume 14 (3). E0212410.

Weihe. P, et al, 2008. Serum concentrations of Polyfluoroalkyl Compounds in Faroese whale meat consumers. Environ Sci Technol volume 42 (16). 6291-6295.