Why does a woodpecker have such a long tongue?

That’s just one of the questions that visitors to the new yearlong environment-themed exhibit at the American Visionary Art Museum may find themselves pondering.

“The Secret Life of Earth: Alive! Awake! (and Possibly Really Angry)” is AVAM’s 25th themed exhibit and consists of 88 artworks by self-taught painters and photographers and fabric artists and sculptors. The objects are accompanied by text panels meant to provide a wake-up call about threats to the planet ranging from climate change to plastic pollutants, from over-population to toxic dumping.

There’s a section on why a change of just four degrees centigrade could bring about planetary extinction, and an exhibit of original blueprints for the butchering facility created in the 1980s by the author and animal behavior expert Temple Grandin, who was seeking to lessen the trauma experienced by livestock raised for slaughter.

“Scientists are my favorite visionaries,” said Rebecca Albin Hoffberger, the museum founder and exhibit curator. “They really probe the whys of how we’ve gotten to the point we’re at on this planet.”

But while “The Secret Life of Earth” includes displays that could alarm visitors, the exhibit is chock-full of artifacts that will delight them — including the answer to the question about the woodpecker’s tongue.

According to the wall text, the artist and inventor Leonardo da Vinci dissected a woodpecker and found that it has a special cavity encircling its brain. It is into this chamber that the bird retracts its tongue, providing a cushion for the delicate organ while its beak jackhammers away at a tree trunk.

So much for being a bird brain.

Below are five other not-to-miss artworks:

“TBD” by Judith and Richard Lang, 1999 — 2019

Dangling from a long and narrow ceiling above a walkway and painted the deep blue of the Pacific Ocean hangs the adult equivalent of an infant’s crib mobile. Hundreds of plastic objects, from a toy soldier to a woman’s hair curler to the remnants of a sand shovel waft gently in a breeze from heating vents.

Since 1999, the artists Judith and Richard Lang collected these objects — and literally thousands more — that have washed up on the same 1,000 square yards of California’s Kehoe Beach in the Point Reyes National Seashore.

It’s the first work that visitors to AVAM see as they walk the ramp leading from the front lobby into the galleries, and it’s mesmerizing.

“We live in a disposable culture where we use it, then toss it away,” the Langs wrote in the wall text. “Unfortunately, there is no ‘away.’ Every piece of plastic produced is still with us. As the plastic breaks down, not only is it a visual blight and a grave danger to wildlife, it releases chemicals known to cause many health problems.”

The artists didn’t clean up dirty objects or repair those that are broken. But when massed together, the vibrant primary colors and familiar shapes may make visitors smile.

It’s a condundrum — how can something that looks so cheerful and appealing be so toxic?

“Journal Entries (4 Framed Works)” by Julia Butterfly Hill, 1997 to 1999

“The wind rages…I feel the creaks and groans all around me. My thoughts get lost in the swirling madness.”

Julia Butterfly Hill wrote these words on the back of a cardboard food box during one of the 738 consecutive days and nights beginning on Dec. 10, 1997 that she spent on a platform high in the branches of a California redwood tree.

Four of the environmental activist’s framed journal entries are on view in this show. One page contains — is it a pen and ink drawing of a tree? Or does the sketch show two humans beings, one holding the other horizontally overhead, the second man’s arms and legs dangling like branches?

Hill kept the journal while involved in a war of wills with the lumber company seeking to clear-cut the land. According to Encyclopedia Brittanica, the logger used loudspeakers and floodlights in a failed attempt to force Hill to disembark.

She finally descended on Dec. 18, 1999 after negotiating the safety of redwoods contained in a nearly three-acre buffer zone around her perch. In return, Hill agreed not to tree-sit again on the company’s property.

“Green Monkeys” by Johanna Burke, 2016

Scientists say that the human eye can see more shades of green than any other color. Perhaps that’s why visitors flock around the installation of half a dozen emerald-hued monkeys and apes created by the artist Johanna Burke.

Maybe it’s because the lifesize orangutan, gorilla, mandrill and three monkeys are simultaneously so realistic and so fantastical. More likely, it’s because they’re so beautiful.

Burke’s fiberglass sculptures are adorned with dried plants, seeds and beads made from wood and glass. They originally were created for the 2016 holiday window display in Bergdorf Goodman’s New York store.

The artist has said that natural elements are a trademark of her work, and her lifetime of real-world observation shows. Despite the moss-colored fur, the tassels dangling from their bellies, their bejeweled chest, these simians are oddly lifelike.

The orangutan scratches his head with one hand while another massive paw sporting five perfect fingernails rests on the ground. The orangutan’s eyes appear quizzical; his mouth is slightly open.

He seems to have spied something at close range that puzzles him. Perhaps it’s the two-legged primates lurking nearby?

Driftwood sculptures found by Brian Pardini / “Against Forgetting” by Nina Montenegro

At first, the delicate driftwood sculptures found by the artist Brian Pardini seem proof of human vanity. Do the members of any other species find mirror images of themselves wherever they look?

On view are small pieces of wood that resemble crude human figurines. The effect is uncanny — especially once visitors learn that these mini-sculptures, though carefully arranged to generate the desired effect, haven’t been carved or otherwise altered.

But a nearby artwork by the artist Nina Montenegro makes it more difficult to dismiss these mental associations as anthropomorphism. In “Against Forgetting,” Montenegro has paired a wax rubbing of the crosscut of a tree with an inked human fingerprint.

The rings of the tree and the swirls of the fingerprint line up almost perfectly. It’s almost as if they were cast from the same mold, though if anything, it’s the design of the tree that’s more intricate and complex.

Which is the original masterpiece, visitors may wonder, and which is the cheap knock-off?

Untitled by Santiago Navila, 2019

Visitors who enter the gallery set aside for Santiago Navila’s immersive video installation may instantly feel their shoulders relax. It’s a bit like being inside a cloud.

Hoffberger said that the artist is a monk who studied for two years with the Dalai Lama, so Navila knows how to create an atmosphere promoting tranquil meditation.

The lights have been turned low. Choose a seat from among stacks of pillows of different heights scattered across the gallery floor, while gazing at the bolts of gauzy white mesh that swoop down from the ceiling, cross paths and then double back.

Several cameras discreetly positioned around the gallery project a continuous loop of video scenes from nature onto the fabric bolts: A herd of wildebeest ford a brown river. The animals descend into the stream in a cloud of dust, wade chest-deep through the water, struggle up the opposite bank and then canter through the grass.

Sometimes the sequence of events is reversed and sometimes, depending on the shape of the fabric “screen” on which the video is being projected, the image curves around itself in a semi-circle.

That’s all there is to the installation. But some visitors may find that it has calmed their heartbeat and slowed their breaths.

If you go

The Secret Life of Earth: Alive! Awake! (and Possibly Really Angry!) is at the American Visionary Art Museum, 800 Key Highway, Baltimore, through September 6, 2020. For more information, go to avam.org.