In the wild, real estate is a matter of survival, and some animals have perfected the art of moving into homes they didn’t build. Instead of spending time and energy digging burrows, weaving nests, or carving shelters, these clever opportunists claim ready-made dwellings from other creatures.
Some wait patiently for a vacancy, while others aren’t afraid to evict the original owner outright. Whether it’s a hermit crab swapping shells or a bird taking over a rival’s nest, these natural squatters prove that when it comes to finding the perfect home, possession really is nine-tenths of the law.
The information in this article is collected from online sources and is intended for general informational purposes only. It should not replace professional advice from zoologists, ecologists, or animal behaviour experts.
1. Hermit Crab
Hermit crabs are the best-known home thieves of the sea. Lacking their own protective shells, they occupy the discarded shells of snails and move to larger ones as they grow.
Competition can get intense, crabs have been observed fighting or even forming queues around a desirable empty shell until it becomes vacant. Their entire survival depends on finding the right fit, making shell availability a matter of life or death in crowded coastal waters.
2. Burrowing Owl
Instead of digging their own burrows, these small owls often move into those abandoned by prairie dogs, armadillos, or ground squirrels. The ready-made tunnels offer safety from predators and harsh weather, giving these owls an easy nesting solution on open plains.
Their long legs help them navigate underground passages perfectly. Burrowing owls sometimes decorate burrow entrances with dung to attract beetles, turning borrowed homes into functional hunting grounds.
3. Cuckoo Bird
Cuckoos take home theft to another level by hijacking nests before the eggs even hatch. A female cuckoo lays her egg in another bird’s nest, leaving the unsuspecting host to raise her chick.
The young cuckoo often pushes out the host’s eggs or chicks to claim all the attention. This strategy, called brood parasitism, lets cuckoos avoid parenting entirely while ensuring their offspring get fed by hardworking foster parents who never suspect the deception.
4. Goby Fish
Some goby species occupy the empty burrows of shrimp or other sea creatures. Once inside, they fiercely guard their new homes against intruders.
This arrangement sometimes benefits both, if the shrimp returns, it might share the space while the goby acts as a lookout for predators. The goby’s sharp eyesight compensates for the shrimp’s poor vision, creating an unlikely partnership built on borrowed real estate beneath the waves.
5. Tree Swallow
Tree swallows are cavity-nesting birds that rely on existing holes in trees or fence posts. When woodpeckers abandon their nests, swallows quickly move in.
They often compete with bluebirds and chickadees for these prime real-estate hollows. Their iridescent blue feathers flash as they dart in and out, defending claimed territories with aerial displays. Nest boxes put up by humans have become popular alternatives, easing competition in areas where natural cavities are scarce.
6. Octopus
Octopuses are masters of improvisation when it comes to shelter. Many species move into discarded shells, coconut halves, or even glass bottles on the seafloor.
They use these makeshift dens for resting and hiding from predators, rearranging them as needed, like underwater interior designers. Some octopuses carry their borrowed homes with them, scuttling across the sand while peeking out from their protective shells, ready to retreat at the first sign of danger.
7. Yellow Mongoose
In Africa’s open grasslands, yellow mongooses often occupy abandoned burrows dug by other animals such as ground squirrels or aardvarks. These tunnels provide instant protection from eagles, snakes, and jackals, sparing the mongoose the effort of digging its own network.
Social groups sometimes share these borrowed spaces, with multiple families cohabiting peacefully. The complex tunnel systems offer escape routes and cool retreats during scorching midday heat.
8. House Sparrow
This familiar city dweller doesn’t always build from scratch. House sparrows frequently claim nests left behind by swallows or starlings, sometimes even driving the former owners out mid-season.
Their adaptability and boldness make them one of the most successful opportunists in the bird world. Sparrows thrive in urban environments partly because they’re willing to commandeer any available nesting spot, from building eaves to mailboxes, showing remarkable resourcefulness in crowded habitats.
9. European Starling
European starlings are notorious for aggressively taking over nesting cavities from native birds. Their bold behaviour and larger size give them an advantage when competing for woodpecker holes or bluebird boxes.
Once established, starlings fiercely defend their stolen territory, sometimes destroying eggs or chicks of the original occupants. Introduced to North America in the 1890s, their population exploded partly because of their willingness to claim any available nesting space without hesitation.
10. Cowbird
Brown-headed cowbirds practice a sneaky form of home theft similar to cuckoos. Females lay their eggs in the nests of smaller songbirds, leaving the host parents to raise cowbird chicks alongside or instead of their own.
Cowbird chicks often hatch earlier and grow faster, outcompeting the host’s offspring for food. This reproductive strategy allows cowbirds to produce many more young than they could raise themselves, spreading their genes widely across different host species.
