The animals have arrived.
When nature takes over.
Swarms, migrations, mass gatherings, wildlife takeovers, and those moments when animals show up in numbers too big to ignore.
Featured invasions
You have to see this.
Extraordinary animal events from around the world, with the story behind what you’re seeing.
Great Migrations
Millions of red crabs can take over Christmas Island roads
For a short period each year, roads, bridges, yards, and forest floors can become part of a mass journey to the sea.
Swarms & Infestations
Why cicadas can suddenly seem to be everywhere
A synchronized emergence can turn trees, sidewalks, fences, and backyards into a wall of sound and movement.
Mass Gatherings
When thousands of starlings turn the sky into a moving shape
A murmuration can look like smoke, a wave, or a single giant organism changing direction in midair.
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Great Migrations
The river crossings that make the wildebeest migration look impossible
Huge herds compress into crossing points where movement, dust, water, predators, and panic collide.
Mass Gatherings
What it looks like when a cave releases a river of bats
At major roosts, bats can pour into the evening sky in a stream that seems to keep going long after sunset.
Great Migrations
When a river fills with salmon moving upstream
A salmon run can transform a river into a moving corridor of fish, predators, and concentrated wildlife activity.
Mass Gatherings
When hundreds of thousands of horseshoe crabs cover Delaware Bay beaches
Every spring, Delaware Bay beaches become spawning grounds for enormous numbers of horseshoe crabs, creating one of the East Coast's strangest seasonal wildlife spectacles.
Great Migrations
The sardine run can turn South Africa's coast into a feeding frenzy
Tens to hundreds of millions of sardines can move along the coast, drawing dolphins, sharks, seabirds, and other predators into one moving spectacle.
Swarms & Infestations
When Mormon crickets take over Nevada roads
During outbreaks, enormous numbers of Mormon crickets can cover roads, yards, and agricultural areas, sometimes creating a genuine driving hazard.
Great Migrations
Millions of monarch butterflies can blanket forests in Mexico
North America's eastern monarch population travels thousands of miles south, eventually concentrating in mountain forests where huge clusters can cover trees.
Mass Gatherings
When sea turtles nest together in synchronized waves
Kemp's ridley sea turtles are famous for arribadas, mass synchronized nesting events that can suddenly fill beaches with nesting females.
Swarms & Infestations
Lake Erie can release billions of mayflies in a single night
Mass mayfly emergences can become so large that radar detects them and shoreline communities wake up to streets and buildings covered in insects.
Great Migrations
Snow goose migrations can turn the sky white
Massive flocks of snow geese can gather over wetlands and farm fields during migration, creating a wall of birds, sound, and movement.
Mass Gatherings
Tens of thousands of snakes emerge at the Narcisse dens every spring
Manitoba's Narcisse Snake Dens erupt with red-sided garter snakes each spring as enormous numbers surface from winter dens to mate.
Mass Gatherings
Thousands of fireflies can make an entire forest flash together
For a short period each year, synchronous fireflies in Great Smoky Mountains National Park coordinate their flashes into one of the strangest nighttime wildlife displays in North America.
Swarms & Infestations
A single square kilometer of locust swarm can hold tens of millions of insects
Desert locust swarms can stretch across huge areas, travel long distances in a day, and consume crops at a scale that turns an insect outbreak into a regional emergency.
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Animals taking over a road, beach, yard, town, river, or sky? Send us what you found and where it happened.