Nature’s symphony surrounds us — leaves rustle, insects buzz, frogs croak. Each tone conveys an important meaning. Birds, for example, use alarm calls to warn of danger and songs to mark territory and attract mates.
Even prior to 1949, when scientists first recorded beluga whales, bioacoustic experts were tuning their ears toward the sonance, investigating sound production, dispersion, and reception in animals.
Bioacoustics technology is widely used today, thanks to small, low-cost recording equipment featuring expansive programmability, solar power, data storage, and artificial intelligence. Depending on the type of vegetation and vocalizing species in a forest, these recorders can detect animal calls and songs across a few hundred yards.
These advancements give researchers “a chance to listen to animals that are difficult to study otherwise, so we’re just learning many basic, foundational things about different species, while still developing technology for answering biologically important questions,” says marine biologist Ana Širovic´, PhD.
One such question involves assessing how ship engines and seismic air-gun blasting used in oil exploration may affect marine life, including tiny zooplankton and the critically endangered North Atlantic right whale, says Širovic´. “There’s a lot of impetus to try to understand how that increase in background noise affects animals that produce sound and count on sound for all kinds of biologically important things, such as mating and finding food.”
Studies have shown that air-gun blasting, for example, poses “significant, long-lasting, and widespread impacts on the reproduction and survival” of threatened whales and commercial fish populations.
This is more than a theoretical problem. In 2019 the current administration approved nighttime seismic air-gun-blasting permits in Cook Inlet, Alaska, home to some of the world’s few remaining Cook Inlet beluga whales.
“The noise from these blasts is so loud that it can be heard up to 2,500 miles from the source, which is approximately the distance from Washington, D.C., to Las Vegas,” explains marine scientist Ingrid Biedron, PhD.
Unlike air-gun blasting, camera traps have been quietly making waves in the conservation world for years. But don’t let the word “trap” confuse you: These minimally invasive, remotely activated cameras are equipped with motion or infrared sensors that document natural species behavior, providing important data about known species in a region.
By capturing images of a Javan rhino mother and her calf, for example, researchers have proven that the world’s rarest rhino is breeding. The critically endangered species — it’s estimated that only 68 remain — is expert at evading the humans responsible for its protection.
The cameras have also provided evidence of species thought to be extinct. The silver-backed chevrotain had escaped detection for nearly 30 years, until scientists in 2018 photographed the tiny deer-like animal in forests near Nha Trang, Vietnam.
Camera-trap footage offers promise in an age of bleak news about potential mass species extinction. In the case of the chevrotain, which is threatened by hunting, deforestation, and urban sprawl, scientists hope their images will inspire surveys assessing its population and health.
“Without immediate follow-up action, there is a risk that the silver-backed chevrotain could be lost once again,” the researchers note.
These devices have also emerged as a key tool for capturing the attention of humans. By combining technical skill, studio lighting, and wildlife knowledge, scientists and advocates have used camera traps to create stunning, artistic images that raise awareness about threatened species worldwide.
In Sumatra, which has lost half of its forest canopy since 1985, camera-trap images in the Leuser region have publicized the threats to the 6.5 million–acre ecosystem’s diverse wildlife, including endangered rhinos, elephants, orangutans, and tigers.
The Sumatran tiger population has fallen at an alarming rate due to habitat loss, poaching, the illegal trade of its body parts, capture of live specimens, and conflict between tigers and humans. (It’s listed as Critically Endangered in the Red List of the International Union for Conservation of Nature.)
“Until now, almost no videos existed of most of Leuser’s cryptic wildlife,” says Dutch conservationist and photographer Marten Slothouwer, who led the effort. “Our videos can make people realize that it’s worth it to save this forest.”