Posted on Categories Discover Magazine
The great white shark (Carcharodon carcharias) may seem like the fiercest predator in the ocean, but a recent study indicates they flee when orcas (Orcinus orca) enter their territory. Along the coast of Gansbaai — off the western cape of South Africa, a group of at least two orcas has been harassing and attacking great white sharks. So much so there have been notable ecosystem shifts. Enemies are common in the animal kingdom. Other antagonistic animal relationships stem from one species trying to protect its own from becoming prey. Here are three other animals with known nemeses. 1. Owls vs. Crows The great horned owl is a nocturnal hunter that will snatch birds and hawks from their nighttime nests. For example, an osprey couple living at Hog Island Audubon Camp had at least one chick seized from their nest five years in a row. In turn, some species of birds will harass owls as a strategy to reduce attacks on their own flocks. Crows, in particular, will harass owls they encounter during daylight hours. One researcher observed a flock of crows harassing an owl on an island off the coast of Maine. The owl came to the island overnight to hunt, but a storm prevented it from leaving before sunrise. The crows took the opportunity to harass the owl by mobbing it “constantly,” even as it tried to fly to safety. Seagulls then jumped into the fight and, at times, drove the owl close to the water below. Crows and seagulls are not the only birds to mob owls, and researchers in Australia have observed seven species of birds getting in owls’ faces. Older and more experienced owls that seem unnerved by crow mobbing are eventually left alone. This is likely because mobbing is a risky behavior done by birds that are much smaller and lighter than the owl. But it’s a behavior that pays off, and studies have found that owls are more likely to prey on non-mobbing birds. Read More: The More We Learn About Crow Brains, the More Humanlike Their Intelligence Seems 2. Snakes and Newts The garter snake has long seen newts as a food source, and the newt has long seen the garter snake as a worthy recipient of its deadly toxin. Over time, the newts have become more poisonous, and the garter snakes have gotten even better at tolerating the poisons. Some have called it an evolutionary arms race. The newts’ toxins kill by plugging up molecular pores in muscle and nerve cells. This leads to paralysis and then the end of lung function. The snakes, however, have evolved so that the molecular pores are differently shaped and not fully plugged by the toxin. This evolutionary back and forth has prompted scientists to note that resistance to toxins has existed in reptiles long before snakes originated, which suggests this biological battle royale predates the existence of either species. Not all garter snakes develop the tolerance, and researchers have found it’s based on location and exposure to the newts. Read More: 10 of the World’s Deadliest Snakes 3. Bees vs. Hornets When the Vespa mandarinia, or giant northern hornet, was found in Washington State in 2020, there was cause for alarm. These hornets, dubbed “murder hornets” in many news stories, took down entire hives of honey bees. Only a few hornets in a “slaughter phase” were needed to massacre an entire hive by decapitating the bees. The hornets then claimed the hive as their own. The western honey bee (Apis mellifera) has no natural defenses against the killer hornet. The Asian honey bee (Apis cerana), however, has evolved to be the hornets’ natural enemy. The Asian honey bee has several defenses against hornet hive attacks. One strategy is to place animal feces at the entry of their hive. Scientists suspect the feces contain a property that repels the hornet. The bees also use an offensive attack to take down the hated hornet. When a hornet is detected, defender bees wait near the entrance. They then hit the hornet with a wad of isoamyl acetate, a pheromone released during stinging. The substance both traps the hornet and raises its body temperature to a fatal level. However, Western honey bees need human help fighting their natural enemy. People are encouraged to notify authorities if they see a suspected giant northern hornet’s nest.