Volunteers scoop poop to learn what animals ate

Want to get outdoors, hike some trails and scoop some poop? That may not be everyone’s idea of a great weekend. But for some two dozen volunteers near the Santa Cruz Mountains in central California, picking up animal feces on a hike is part of the fun. These recruits are citizen scientists — volunteers of all ages who want to help researchers.

They’ve joined a project called Conservation Scats. It’s run by Justine Smith and Yiwei Wang at the University of California at Santa Cruz. Starting last summer, they’ve been recruiting volunteers to help study how local predators respond to people who share their woodlands.

More and more, people are building houses and businesses in and near the Santa Cruz Mountains. Smith and Wang want to find out whether this alters the dining habits of local wildlife. The ecologists are especially interested in the medium-sized animals that live off of other animals. Called mesopredators, these animals are smaller than top-level predators such as mountain lions. Local mesopredators in California include bobcats, coyotes and foxes. The foxes are the smallest of the three. Coyotes and bobcats often kill foxes, so foxes tend to hunt at night and stay out of the bigger guys’ way.

All three species generally shy away from people. Bobcats and coyotes can be active day or night. But because people are outside during the day, Smith and Wang think these mesopredators might be hunting more at night, when foxes eat. And that may change the diet of each.

By day, bobcats and coyotes might dine on squirrel and other animals active during sunlit hours. At night, the predators might switch to mice and rats, prey active after dark. And this might be bad news for foxes. Bigger predators might be scarfing down their night-time buffet. That’s why Smith wants to know if the bobcats and coyotes are changing their diets to eat more nocturnal — or night-active — creatures.

To find out what the mesopredators are eating, she will need their scat.  Some of each meal will leave traces of its source as DNA in those feces. DNA is a molecule that tells cells which molecules to make. Each species has its own unique DNA. So by examining DNA in the feces, the scientists will be able to find out on which prey an animal had been dining. 

But DNA is very delicate. If scat sits in the sun too long or if it gets wet, the DNA inside could break down. So, the scientists want fresh feces hosting fresh DNA.

Their volunteers won’t just collect scat. They also will kick the poop. “One weekend we go out and throw all the scat off a trail,” Smith notes. “We call it scat cleaning, but really it’s scat kicking and throwing,” she says. The next week, the volunteers return. Now, they carry plastic bags and wear gloves to protect themselves from any germs in the poop. As they hike, volunteers collect every bit of feces visible near their assigned trail. The citizen scientists carefully note where they found each deposit.

Picking up poop in plastic bags may not sound glamorous, but the volunteers love hiking with a purpose. “I am out every day in the mountains and love it when I have a ‘job’ to do,” says Biz Eischen. She’s a writer who lives in Los Gatos, Calif. And she’s volunteered for Conservation Scats since the project began. “I like to help,” she explains. “I’m interested in science and the environment. Most of all, I want to know what [Smith] discovers!”

Smith carefully separates each scat into pieces. She stores those pieces in small vials in a freezer. The samples are also frozen in special chemicals to preserve the DNA she needs. Right now, she lacks the money to study that DNA. But when she gets it, her specimens will still be ready.

Finding out what the predators eat and how their diets are changing could help scientists figure out how these mid-level predators survive in an environment filled with people. “We all hear about what happens when people move in and animals disappear,” says Smith. “But a lot of animals persist. They just change their behavior.”

If bobcats and coyotes dine on what foxes eat, it might be time to give the smaller of these mid-level predators more space. For instance, Smith explains, “we might need to reduce disturbance. Maybe reduce trail use or try to reduce light and sound pollution.” But understanding what the predators are eating is the first step. And knowing that comes down to studying their scat.

To volunteer, leave a message on the Conservation Scats webpage. The next poop hunt will be posted at the end of February 2015. 

Follow Eureka! Lab on Twitter

Power Words

(for more about Power Words, click here)

citizen science  Scientific research in which the public — people of all ages and abilities — participate. The data that these citizen “scientists” collect helps to advance research. Letting the public participate means that scientists can get data from many more people and places than would be available if they were working alone.

conservation  The act of preserving or protecting the natural environment.

DNA  (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.

ecology  A branch of biology that deals with the relations of organisms to one another and to their physical surroundings. A scientist who works in this field is called an ecologist.

feces  A body’s solid waste, made up of undigested food, bacteria and water. The feces of larger animals are sometimes also called dung.

mesopredatorA mid-sized animal that eats other animals for its food. Mesopredators are smaller than top-level predators such as mountain lions. Examples include raccoons, foxes, bobcats and coyotes.

nocturnal    An adjective for something that is done, occurring or active at night.

predation  A term used in biology and ecology to describe a biological interaction where one organism (the predator) hunts and kills another (the prey) for food.

predator  (adjective: predatory) A creature that preys on other animals for most or all of its food.

scat  The feces shed by a wild animal, usually a mammal.