Species Most at Risk: Who’s Paying the Highest Price

Every day, countless animals lose their lives on roads around the world. But some species are more vulnerable than others. Factors such as size, speed, behavior, and even reproductive rate determine which creatures are most at risk from vehicle collisions. While it’s often assumed that small, common animals make up most of the losses, studies show that even large and endangered species are paying the price. Understanding who is most at risk helps us see the true scope of the problem — and why prevention matters not just for biodiversity, but for the health of entire ecosystems.

Among U.S. wildlife, few species are as threatened by road collisions as the Florida panther, which suffers the highest proportion of deaths caused by vehicles of any large mammal in the country. With an estimated population of fewer than 200 individuals, vehicle strikes remain the leading cause of mortality, accounting for over 25 deaths each year—an alarming figure given the species’ fragile numbers. Other animals, such as the San Joaquin kit fox in California and the Key deer of the Florida Keys, also face disproportionate losses due to roads cutting through their limited habitats. While deer and smaller mammals make up the majority of total roadkill incidents, their populations are large enough to recover. For endangered species like the Florida panther, however, each road death represents not just an individual loss but a significant step toward extinction.

Globally, road networks are expanding at an unprecedented rate, often slicing through critical habitats. For wide-ranging species that need large territories, such as wolves, bears, and big cats, roads create dangerous barriers. In Brazil, the giant anteater (Myrmecophaga tridactyla) has been hit particularly hard; research shows that road mortality has reduced the growth rate of some populations by nearly half. Because these animals reproduce slowly and travel long distances, each individual lost represents a major setback for the species as a whole.

In Europe, the Iberian lynx — one of the world’s most endangered cats — faces similar challenges. In parts of Spain and Portugal, vehicles are one of the leading causes of death for these animals, accounting for as much as 80% of known mortalities in some populations. While conservation efforts have helped lynx numbers rebound slightly, road collisions continue to threaten their recovery.

Australia’s Tasmanian devil is another species under pressure. Once widespread, this nocturnal scavenger now faces a combination of disease and deadly roads. Studies have shown that roadkill is not just an additional threat — it may be enough to push local populations toward collapse if not addressed. Because devils are drawn to carrion, they are often struck while feeding on other roadkill.

Across Africa and South America, species such as the African wild dog, maned wolf, and little spotted cat face a similar fate. These mid-sized carnivores travel long distances in search of food and mates, frequently crossing roads that fragment their ranges. A 2023 study led by the University of Central Florida found that if current roadkill rates persist, some populations of these species could face local extinction within a few decades. Even for species not yet endangered, frequent losses can tip the balance toward long-term decline.

Smaller creatures are not immune either. In Europe, the hazel grouse, russet ground squirrel, alpine shrew, and several species of mole rats and bats have been identified as particularly vulnerable. These animals tend to move slowly, stay close to the ground, or are active at night — all factors that increase their risk of being struck. Because they’re less visible and often unrecorded in roadkill surveys, their true mortality rates are likely underestimated.

The reasons these species suffer disproportionately often come down to biology and behavior. Animals with slow reproductive rates or long lifespans, such as large mammals, can’t easily replace lost individuals. Wide-ranging species encounter roads more frequently as they move through fragmented habitats. Nocturnal or crepuscular species, like many bats and carnivores, are active when visibility is low. Some are drawn to roadsides for warmth, salt, or food — increasing the likelihood of fatal encounters. And when populations are already small or isolated, every roadkill death carries greater ecological weight.

If trends continue, the long-term implications could be severe. Scientists warn that for certain species — including the maned wolf, brown hyena, and Iberian lynx — roadkill mortality alone could determine whether local populations persist or vanish. For others, frequent losses could erode genetic diversity, making them less resilient to disease and environmental change.

The loss of these species doesn’t just affect biodiversity; it impacts entire ecosystems. Predators regulate prey numbers, scavengers recycle nutrients, and birds and mammals disperse seeds that sustain forests and grasslands. When roadkill removes key players from these systems, the ripple effects can alter everything from soil health to carbon storage. Protecting wildlife on roads, therefore, isn’t just about saving animals — it’s about safeguarding the intricate balance that supports life itself.

For the wild.

References

• Federal Highway Administration (FHWA), Wildlife-Vehicle Collision Reduction Study (2008)

• Florida Fish and Wildlife Conservation Commission (FFWCC, 2024 data)

• Scientific American — “Roadkill Endangers Endangered Wildlife” (2023)

• Insurance Information Institute (2023)

• Loss, S. R., et al. (2014). Estimation of bird–vehicle collision mortality on U.S. roads. Journal of Wildlife Management.

• University of Reading (2021). Vehicle collisions threaten survival of Iberian lynx.

• The Conversation (2023). Roadkill: Vehicle collisions may be threatening the survival of some mammal populations.

• Nottingham Trent University (2023). Impact of roadkill worse than thought; some mammal populations could reach tipping point.

• University of Central Florida (2023). New study shows impact of roadkill on world’s vulnerable animal populations.

• Grilo, C. et al. (2020). Roadkill risk and population vulnerability in European birds and mammals. Frontiers in Ecology and Evolution.