Hot weather, especially the 104 degree Fahrenheit / 40 degree Celsius we had here two weeks ago on the East Coast (after it had baked the Midwest) makes many of us want to take the advice of the Center for Disease and Control: Stay inside with the air-conditioning on. Who among us doesn’t excessive heat make more irritable, cranky, sluggish, in a generally not-happy-with-the-state-of-the-world state of mind? Heat like that in parts of Texas where it’s been at least 100 degrees F (38 degrees C) for 39 straight days often only seems to bring out the atavistic “I’m in it for myself” tendencies in some, as tragically attested by death of a 79-year-old Texas woman. Dolores Grissom died in her home two days after reporting the theft of her air-conditioning unit to police.
Writing at Scientific American, Jason R. Goldman describes how, for one bird, the Kentish plover (Charadrius alexandrinus), extreme heat leads rather to more cooperative behavior. It gets up to 140 degrees Fahrenheit (60 degrees Celsius) where Kentish plovers in the Saudi Arabian desert live. But, according to a study published in the Animal Behaviour, the extreme heat of the desert actually leads to male and female Kentish plovers working together to protect their eggs from the heat by taking turns sitting on them.
Biologist Monif Al-Rashidi and colleagues found that the male and female Kentish plovers take turns incubating their eggs, allowing their partners the chance to cool-off by “belly-soaking” in the Red Sea. They also found that, when the eggs and nest are out in the open (where it’s safer as it’s easier to detect predators), the males and females “spot” each other more frequently than they do when the eggs and nest are in the shade (where it’s more difficult to spot predators and, therefore, potentially more dangerous). As Goldberg writes:
The Kentish plover provided Al-Rashidi with the opportunity to conduct a particularly clever experiment. These birds lay their eggs on the ground, which means that the eggs as well as both parents have direct exposure to the surrounding environment. Some nests are located under bushes, and are therefore naturally protected from direct sunlight, while others are out in the open. This provided an obvious way for Al-Rashidi to create two experimental groups – one in direct sunlight and a second in the shade. In general, males tend to sit on the nest during the cooler nighttime, while females tend to take the daytime shift. The problem is that the females risk overheating if they incubate the eggs all day. The harsh environment hypothesis, therefore, predicts that the warmest nests will not only show evidence of more biparental care but that the two parents will take turns more often throughout the day.
Here’s a video of Kentish plovers in Saudi Arabia:
Al-Rashidi’s and his colleagues’ research suggests that “turning up the heat can lead to increased cooperation.” Bringing on the heat can make some animals act, in essence, better — a lesson whoever stole Grissom’s air-conditioning unit and more than a few of us humans would do well to learn.
Related Care2 Coverage
Photo of Kentish plovers (in California, not Saudi Arabia) by mikebaird