Mammalogists tend to specialize in the study of the systematics, anatomy, physiology, ecology, or behavior of a particular taxonomic group or assemblage of mammals, such as bats, canids, or rodents. On the other hand, epidemiologists use scientific, systematic, and data-driven approaches to determine the cause, risk factors, and the frequency and pattern of diseases that affect wild mammal populations.
Bats play an important ecosystem role by eating insects, including those that annoy us (such as flies), spread disease (mosquitoes), and cause widespread crop damage. However, some bat species populations in the state have declined drastically in the last decade. Illinois bat species face challenges such as white-nose syndrome and habitat loss, making conservation and management efforts essential.
INHS mammalogists collect the data needed to inform conservation and management efforts by conducting statewide bat monitoring. Survey methods include capturing, identifying, and banding individuals and collecting acoustic recordings of high-frequency bat calls.
General bat surveys
The Illinois Bat Conservation Program (IBCP), led by INHS, conducts research and statewide monitoring of Illinois’ 13 bat species. Annual surveys establish bat species distribution and long-term population trends.
In a recent project at Coles County’s Warbler Ridge Nature Preserve, the IBCP team collected acoustic bat calls and captured bats using mist netting to determine relative bat activity and which species were residing in the preserve. The non-profit Grand Prairie Friends then planted trees and pollinating plants, added wetlands, and erected a total of 12 artificial roosts in two locations within Warbler Ridge. IBCP scientists monitored the improved habitat, confirming that the restoration efforts were successful and bat populations were gradually increasing.
Bat surveys to support infrastructure maintenance and development
INHS mammalogists travel the state searching for signs of bats in, under, and around bridges and culverts—structures that bats can use as roosts. These surveys are done in association with the Illinois Department of Transportation (IDOT) to help IDOT staff avoid harming bat populations while repairing, cleaning, or demolishing bridges and culverts.
Field surveys are conducted through capture-and-release programs using mist nets. The reproductive state, age class, weight, and overall condition of each captured bat are determined, and the animals are released at the point of capture.
Scientists have also surveyed over 50 overpasses for bat activity in Illinois and deployed over 60 acoustic monitoring stations to assess impacts to bat populations within the Tollway network. These efforts assist with initiatives to monitor and conserve declining bat populations in the region.
Wind energy impact on bats
INHS biologists may help mitigate the impacts of wind energy on the state’s wildlife. Using acoustic monitoring, they can determine where bats are most active across the state. This information is shared with the Illinois Department of Natural Resources and U.S. Fish and Wildlife Service to inform siting of new wind farms.
Working with IDNR, INHS biologists assessed the effectiveness of a cave gate installed by Pioneer Wind Farm to allow free passage of native bats and protect against the spread of white-nose syndrome. Working with Apex Clean Energy and the not-for-profit Grand Prairie Friends, INHS has conducted monitoring of bat biodiversity and has installed artificial bat roosts to expand bat habitats in east central Illinois.
Bat genomics and genetics
Scientists in the Collaborative Ecological Genetics Lab partner with the U.S. Fish & Wildlife Service to conduct bat population genomics assessments of endangered Indiana bats using tissue samples. If bats residing in a structure are genetically diverse, conservation protection plans for these mammals will be significantly different than for less diverse populations. Conservation genomics is an approach allowing researchers to learn more about bat populations after just a few nights of data collection compared with traditional studies that can require years of observation.
In an effort to maximize the use of each tissue sample collected from live bats, scientists at the Wildlife Veterinary Epidemiology Lab conducted genetics work that has helped determine that researchers can use the same sample for additional research projects on bat genetics instead of discarding the sample after being used only once for one particular analysis. In addition, the laboratory is collaborating with INHS mammalogists to organize and catalog deceased bats that had been tested for rabies dating back to 2006.
Chronic wasting disease
Epidemiologists in the INHS Wildlife Veterinary Epidemiology Lab led by Nohra Mateus-Pinilla study how chronic wasting disease (CWD), a slow, deadly, incurable neurological disease, spreads among deer.
The laboratory research group has collaborated with the Illinois Department of Natural Resources wildlife biologists since 2002 to help support the surveillance, management, and health protection of wild deer in Illinois. Mateus-Pinilla measures the cases of CWD in the deer herd, studies changes in the number of new cases during a specific period, and analyzes factors contributing to disease spread. In addition, recent studies have focused on the geographic distribution of CWD among free-ranging white-tailed deer populations and genetic expressions that may influence the predisposition of deer to CWD infection.
As a result, the CWD surveillance program helps inform the public about CWD-infected areas. Mateus-Pinilla has collaborated with landowners and hunters to evaluate changes in disease and factors that may contribute to the effectiveness of the state’s strategy in maintaining the low prevalence of CWD in the herd. Early detection of CWD helps inform management decisions to decrease disease spread and protect the health of the deer herd.
Risk perception of chronic wasting disease
Chronic wasting disease (CWD) has been found in Illinois white-tailed deer populations, presenting signs of severe weight loss, stumbling, and other neurological manifestations of the disease that interfere with eating, drinking, and orientation. The disease is fatal to animals, but there have been no reported cases of CWD infections in humans.
Researchers with the Human Dimensions Research Program studied hunters’ and the nonhunting public’s perceived risk of being exposed to CWD through surveys sent eight years apart to ascertain how these risks may influence hunter behavior, such as quitting hunting or not eating venison. Results showed that perceived risks associated with CWD declined over eight years as the disease was no longer new nor a focus of media attention. Over time, hunters also tended to believe they can identify CWD-positive deer and take precautions. These types of studies inform management decisions and highlight societal consequences of wildlife diseases.
Epizootic hemorrhagic disease
Epizootic hemorrhagic disease (EHD) is a severe vector-borne viral disease that affects hooved animals, especially white-tailed deer. The virus (EHDV) is transmitted by biting midges, also known as no-see-ums or punkies. At the Wildlife Veterinary Epidemiology Lab, researchers investigate EHD outbreaks in Illinois and the receptors involved in the response of white-tailed deer to EHDV. The gene expression of this receptor may have a beneficial impact on the ability of deer to respond to EHD.
Read more about INHS infectious disease research.
At the Wildlife Veterinary Epidemiology Lab, Nohra Mateus-Pinilla and the multidisciplinary group of collaborators study wildlife affected by infectious diseases and environmental contaminants. Some of the pathogens evaluated include toxoplasma gondii (Toxoplasmosis), borrelia burgdorferi (Lyme disease), leptospira bacteria (Leptospirosis), and West Nile virus. In addition, researchers at the lab have evaluated contaminants affecting aquatic mammals, such as river otters, and the fungal community of cave soils in Illinois that could contain pathogenic fungi and affect bats and other mammals that use these caves as homes. Some mammal species evaluated include raccoons, opossums, feral cats, river otters, woodchucks, skunks, weasels, and rodents.
INHS ecologists in the Max Allen Carnivore Ecology Lab study various ways to estimate populations and the dynamics of large Midwestern carnivores, such as bobcats and bears. Research also focuses on interspecies interactions among carnivores and the effects they have on their ecosystems.
Rather than relying on laborious counting of individual bobcats in the woods after dark, researchers use mandatory hunter reports and modeling techniques to more accurately determine bobcat and other mammal population trends. This information is important for wildlife managers that track animal groups to control populations, plan conservation efforts, and determine the number of permits to provide to hunters and trappers each year.
An important aspect of determining how to manage large carnivores in the state is considering Illinoisans’ perceived risks of encounters with these animals. Researchers in the Human Dimensions Research Program study Illinois residents’ attitudes and beliefs about the recolonization of black bears, cougars, and grey wolves in Illinois since some nearby states have growing predator populations. Public opposition could strongly influence specific management actions.
Carnivores outside the United States
Leopards, tigers, and other large carnivores found in exotic locations are studied to understand behaviors and aspects of ecology that no one has previously recorded. In one study, INHS wildlife ecologists used motion-sensitive camera traps to capture and document behaviors of 39 animal species in Sumatra, Indonesia, including Sumatran tigers and elephants, Sunda clouded leopards, and Malayan sun bears. The frequency and sightings showed that tigers are most active during the day, particularly around midday. Species that compete with tigers, such as leopards, become scarce when tigers are out on the prowl.
With data from camera traps, scientists use analytical techniques to estimate carnivore densities. This type of investigation aids our understanding of how wildlife populations are faring and what factors contribute to their success, information that is vital to conserving species in the wild.
The INHS Mammal Collection contains more than 15,000 catalogued specimens (skins, skeletons, and skulls) of 163 species from 25 families, with just over half (51 percent) of the specimens from Illinois. The mammal collection’s database is searchable and includes specimen information and digitized specimens.