An adult male Pacific Wilson's warbler,
, feeding a fledgling brown-headed cowbird,
Brown-headed cowbirds make offers other birds cannot refuse. Either care for the cowbird’s eggs or something real unfortunate-like will happen to the other bird’s offspring and nest. Capisce? Mother cowbirds lay their eggs in songbirds’ nests, a behavior known as brood parasitism. The songbirds then raise the large, aggressive cowbird chicks, which reduces the care the songbird’s own young receive.
If a bird dares to throw the cowbird’s eggs from the nest, the female cowbird will trash the defiant bird’s nest and smash its eggs. Bird ecologists suggest that host birds may allow the cowbird to lay eggs in the hosts’ nests because of this fear of retribution.
"Retaliatory mafia behavior in cowbirds makes hosts' acceptance of cowbird eggs a better proposition than ejection," said Jeff Hoover of the University of Florida, author of the PNAS study that exposed the cowbird extortion racket, in a press release. "The accepting warblers in our study produced more of their own offspring, on average, than those where we ejected cowbird eggs."
Whale sharks pose little threat to human life. However, these 40-foot fish can take a bite out of fishermen’s profits, because the sharks have learned to suck fish out of nets. Residents of the Filipino fishing village of Tan-awan have turned the massive marauders into tourist attractions. Large numbers of the sharks gather in the area because the locals feed them. Tourists also gather in droves because they want to swim with the leviathans.
Jaguars chew leaves from the vine Banisteriopsis caapi, which contains psychoactive chemicals. Under the influence of the leaves, jaguars roll around like a house cat high on catnip.
The Piaroa tribe believes jaguars’ sensory perceptions and hunting skills increase after eating the leaves, according to research published in the Journal of Psychoactive Drugs. Piaroa hunters copy the cat by taking the drug themselves and believe it improves night vision and strength.
A masked flowerpiercer,
, pierces a flower in Manizales, Colombia.
Master burglars use lock picks to open doors. Likewise, the beak of the flowerpiercer has evolved to break into flowers and feast on the sweet nectar hidden inside.
Normally an insect or hummingbird has to sip nectar through a flower’s specialized petals and other structures designed to ensure that the plant’s pollen coats the nectar nibbler. The pollen-powdered animal then moves on to spread the flower’s pollen and thereby fertilize other flowers.
Flowerpiercers poke holes directly into the bases of flowers. This gives them direct access to rob all of the flower’s nectar, but eliminates the pollination benefit for the plant.
Baboons near Ta'if, Saudi Arabia, appear to kidnap puppies and raise the dogs in their baboon troop. In the disturbing video from the British documentary series “Animals Like Us,” a male Hamadryas baboon (Papio hamadryas) grabs a feral puppy and drags it back to his troop of monkeys. Later footage shows baboons grooming another dog that follows the troop and seems integrated into the monkeys’ social system.
Biologists don’t fully understand baboon kidnapping of puppies. An expert on Middle Eastern feral dogs noted in Psychology Today that male baboons kidnap young female baboons. Perhaps puppies trigger that instinct, and the male baboon intends to raise the puppy as part of his harem.
Like gangsters cruising for an opportunity to whack an unsuspecting rival, chimpanzee raiding parties attack and kill members of other chimp groups. Chimps on the warpath move in stealthy single-file lines through the forest and enter neighboring groups’ territories. If the raiders encounter a smaller, weaker number of rivals, they attack. The ape attackers beat the outnumbered individual to death, frequently tearing off their ears, testicles and other appendages. Picking off rivals allows the aggressive apes to expand their territory and increase their own population.
Like kamikazes in World War II and modern suicide bombers, worker honey bees use suicide attacks to defend their hives. When the bee attacks, its barbed stinger often embeds into the skin of the victim (shown here). When the bee flies away, the stinger remains in the victim along with muscles that continue to pump venom. The worker bees give their lives in defense of the hive, because the loss of its stinger kills the bee.
Against other insects, honey bee workers can sting without losing their guts, because the stingers’ barbs don’t catch in victims’ exoskeletons. Honey bee queens don’t have barbed stingers. Queens can attack many times with their non-stick stingers.
Several species of ant enslave members of other species. For example, Protomognathus ant queens invade the colonies of Temnothorax ants and kill the reigning queen and other adult ants. The remaining Temnothorax pupae, an early ant growth stage, develop into adults that serve as slaves for the Protomognathus invader. The ant slaves care for the conquering queen’s offspring. The enslaved Temnothorax thereby nurture the next generation of invaders that will go out to enslave more colonies.
However, ant slaves can take a cue from Spartacus and rise up to slaughter their overlords. Ant slave rebellions exterminate approximately two-thirds of invading ant pupae, according to research published in Evolutionary Ecology.
A model of a bombardier beetle: The cross section shows the venom glands and reservoir and explosion chamber.
Bombardier beetles spray a cloud of stinging liquid when threatened. The insect produces two chemicals, hydroquinone and hydrogen peroxide, in separate internal containers. When under attack, the beetle allows the chemicals to mix with water and enzymes in a third compartment. The mixture reaches high temperatures and explores out of the beetle’s backside.
Roving black bears sometimes break into homes seeking delicious human food. This summer, seven home invasions and backyard burglaries were reported in Norfolk, Conn., by Norfolk Now. One party animal even chugged a whole pitcher of sangria. Other bears stole butter from refrigerators and ice cream from freezers.
To discourage bears from raiding homes, wildlife managers recommend keeping doors and windows locked and avoiding leaving food outside. Bear-proof trashcans (shown here) can keep bears from becoming accustomed to finding easy meals.