3 March marks the . The article below, published within the framework of this international observance, is based on the personal reflection of one of our interns, with a reminder of how wildlife connects with us and the future of our planet.

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Everyday our lives are touched by wildlife: students admire fierce tigers restrained in a zoo, office workers dodge rats in the subway, children secretly applaud the tenacity of a gecko climbing up the school’s glass window, or you feel soothed by a beautiful bird singing in the morning.? We tend to take these interactions for granted, but they can provide us with a different perspective: humanity is part of a larger interconnected ecosystem that all depends on each other.

My name is Montana Stone, and I am a graduate student studying biology at the University of Manitoba, Canada. When I was younger I pictured my life as being a biologist like Jane Goodall, traveling with a pair of binoculars through a rainforest wearing khaki and beat up sneakers. Maybe even better, I could wear a lab coat and hold test tubes. But most days I read scientific literature, plan projects from afar, analyze data and communicate with other scientists from around the world on the status of our collaborations. I am fortunate enough to work with some of the most threatened species in the world, including the Javan rhinoceros (Rhinoceros sondiacus), which is considered to be the most critically endangered land mammal on the planet.

My work with the Javan rhinoceros began when I was an undergraduate student at Cornell University in the United States, and was invited to participate in a summer-long project where I partnered with a veterinary student to gain international experience in conservation research. I was a second year student when I first heard of the Javan rhinoceros, which like the other four species of rhinoceroses on Earth, are large mammals with horns atop their nose which are often the target of illegal hunting. The Javan rhinoceros is unique because an individual has not been in captivity for over 100 years, and the entire species has a total global population of less than 80 all residing in a single national park in Indonesia.

I spent three summers in Indonesia working on projects to support Javan rhinoceros and the communities that border their habitat. My main project with Javan rhinoceros was piloting research into their voices using automated microphones. From very early and limited pilot studies we were able to distinguish several different vocalizations made by the rhinoceros, like the soft ‘moo’ call of the calf to the mother rhinoceros or the loud and aggressive trumpet call between unsure adult male rhinoceroses as tensions escalate.

While most people think of wildlife vocalizations as simple bird songs or a dog’s bark, animal vocalizations are a large part of “bioacoustics”, the study of how sound is produced, distributed and received in animals. For endangered species like the Javan rhinoceros, bioacoustics can give insight into basic knowledge of the species otherwise unknown. This field of study allows researchers like me to ask questions like: Do rhinoceros ‘speak’ in a certain way during breeding season? Does a large number of aggressive vocalizations between male rhinoceroses in close proximity to each other mean that the species’ habitat is reaching its maximum capacity? Do gunshots recorded in a national park indicate active poaching of endangered species?? If we played a recording of calm voices of an adult female rhinoceros to a rhinoceros during its translocation to a new habitat, will it reduce overall stress levels of the animal? For now these questions are still too advanced for us to answer, but early pilot studies look promising.

So why should you care about the sounds a rhinoceros makes in a small island in Indonesia? That is a fair question, and precisely why the United Nations celebrates World Wildlife Day on 3 March. Each year, this commemoration promotes a new aspect of wildlife conservation, and this year’s theme is Recovering key species for ecosystem restoration. The definition of ‘key species’ varies between biologists, but for most of them it means a species that plays a pivotal role in their ecosystem such that their complete extinction would change its habitat and impact all organisms that rely on it, forever. The Javan rhinoceros is a prime example of such a species, demonstrating how entire ecosystems are linked and that humans, animals and environmental health are intertwined.

The rhinoceros is a ‘habitat modifier’, meaning that as it walks through the dense Javan rainforest, it establishes trails, controls plant growth, disperses seeds, and fertilizes soil. If the species went extinct and did not perform its role as a habitat modifier, ecological balance would not be maintained. Biodiversity would likely decrease and the human communities that rely on that rainforest for food, medicine and other livelihoods would have to seek other venues. That would result in people having to travel farther for food, often at higher costs for less nutritional value.

I am often asked if I still have hope for critically endangered species like the Javan rhinoceros, and I always say that we can have nothing but hope. Like many complicated international projects, rhinoceroses will not be saved with projects derived from a single discipline. Researchers, veterinarians, educators, engineers, government officials and others will decide the future of the Javan rhinoceros, together, and for that I am hopeful.