A new study exploring the link between animal extinction, value on the illegal wildlife market, and body size has determined that many large animals are in "double jeopardy" of extinction. This is especially the case for animals that fetch the highest prices, such as elephants, whale sharks, tigers, and rhinos.

While these megafauna only make up about 5% of protected species, their killing is highly controversial and intensely scrutinized by a public that has deemed them banner species to rally around for the cause of animal conservation. If something isn't done to protect them soon, they will eventually fall prey to human-driven extinction like many other large mammals that no longer roam the Earth.

"Most people are probably aware of the plight of large animals like elephants and tigers that are hunted for products like ivory and skins," Loren McClenachan, an environmental studies professor at Colby College and co-author on the study, told Fusion. McClenachan said these animals have two things working against them: The extremely high value of their parts, which gives poachers incentive to hunt every last one of them, and their large size, which means it "takes them a long time to replace themselves."

"This is what we call ‚Äėdouble jeopardy‚Äô‚ÄĒthe combination of social and biological factors that together create extreme risk of extinction," said McClenachan.

According to McClenachan, this goes against the typical assumption that if a species is reduced to a low enough number where individuals are hard to find, hunters will stop hunting and a certain level of recovery will become possible.


McClenachan said she and Andrew Cooper and Nicholas Dulvy of Simon Fraser University in Canada undertook the analysis, published in Cell Press journal Current Biology, in order to find out whether value was driving the extinction of these animals. They especially focused on large ocean animals, like sea sharks, that are also in peril but have received less conservation attention than their land-based counterparts. Their analysis determined that large ocean animals face the same high risk of extinction as large land animals.

McClenachan said she was surprised that individual marine animals are as valuable as the most valuable species on land. She said this is because ocean animals have bigger parts, meaning more quantity to account for any difference in value.


"The highest value product we found was tiger penis, which is used in traditional Asian medicine," she said. "No offense to tigers, but their penis is very small relative to their body size. In contrast, shark fins for large animals like whale sharks can be massive, and so large individuals have a potential value much greater than you might think given the per pound value of their fins."

Interestingly, the researchers found that unlike land animals, which have a lower risk of extinction the more area they inhabit, for marine species this doesn't necessarily hold true. This is because terrestrial boundaries are easier to protect and conserve whereas ocean creatures are free to travel anywhere.

McClenachan explained that these large ocean ranges might actually be a "detriment to survival" because of how difficult it becomes to coordinate on conservation. She said they found that large, valuable marine animals are found in four times as many countries (or their waters) on average as large, valuable terrestrial animals‚ÄĒwhich means four times as many countries need to help protect them. Big marine animals also migrate over vast distances, rendering smaller ocean preserves ineffective at protecting them.


"Our results help show that we need to catch up even more to reduce the massive difference in the level of protection on land and in the sea," said McClenachan.

In order to explore the relationship between extinction risk, value, and body size the researchers looked at a diverse group of more than 100 large marine and terrestrial species targeted by international luxury markets. They found that most valuable species are at a high risk of extinction regardless of their size, and once the mean product value surpasses $12,557 per kilogram, body size no longer drives risk.

According to the study, the most valuable marine species, the whale shark, has a maximum potential value of $341,140 in traded parts, nearly equal to that of the most valuable land species, the white rhinoceros, at $368,000, and tiger, at $350,193.


They found that five animal products were actually more valuable than gold, which goes for around $38,900 per kilogram. Four of these‚ÄĒtiger penis, bear gall bladder, rhinoceros horn, and deer musk‚ÄĒare used in traditional Asian medicine. The fifth, Tibetan Antelope fur, is primarily used for decoration. Marine products, including shark fins, sawfish rostra, turtle shells, walrus ivory, and devil and manta gill plates, had maximum values ranging from $512 to $1,697 per kilogram.

Courtesy of McClenachan et al., Rethinking Trade-Driven Extinction Risk in Marine and Terrestrial Megafauna, Current Biology

As for solutions to the problem of illegal wildlife killing, the study shows that efforts to date fall far short. In order for poaching fines to be effective, they have have to be ten to 100 times greater than they are right now, according to the study, which states that "fines need to be far greater than the value per animal to disincentivize hunting."


A recent UN and Interpol report found that the value of environmental crime is soaring and that it's now the fourth largest illicit enterprise after drug smuggling, counterfeiting, and human trafficking

Despite all these challenges, McClenachan remains optimistic that large, valuable animals, especially marine animals, can get the help they need to skirt extinction. She noted how campaigns to reduce demand for shark fins have started to shift consumption habits in China. She also thinks control of international trade that has worked for some terrestrial species could work for ocean dwellers, especially since these trade networks are relatively undeveloped and concentrated in a few spots. Technology that helps link products back to the animals they originated from could also prove essential in fighting poaching.

For now, elephant, rhino, tiger and other large, valuable animal populations continue to hemorrhage. Humans are the ones that brought them to this precipice, with a concerted effort we can help walk them back.