Once believed to be unique to birds and mammals, sleep is found across the metazoan kingdom. Some animals, it seems, can’t live without it, though no one knows exactly why.
Some sleep researchers are fond of saying that all animals sleep; that sleep is maladaptive because it takes time away from activities that appear more adaptive, such as mating, seeking food, and looking out for predators; and that no one knows the function of sleep. A good case can be made that each of these statements is false.
To say whether an animal sleeps requires that we define sleep. A generally accepted definition is that sleep is a state of greatly reduced responsiveness and movement that is homeostatically regulated, meaning that when it is prevented for a period of time, the lost time is made up—an effect known as sleep rebound. Unfortunately, the application of this definition is sometimes difficult. Can an animal sleep while it is moving and responsive? How unresponsive does an animal have to be? How much of the lost sleep has to be made up for it to be considered homeostatically regulated? Is the brain activity that characterizes sleep in humans necessary and sufficient to define sleep in other animals?
The reliability rate reported by an Italy-based team in the Journal of Urology comes from the latest of several studies stretching back decades and raises the prospect of canines’ sense of smell helping doctors identify a number of human cancers and infectious diseases.
The two female dogs sniffed urine samples from 900 men, 360 with prostate cancer and 540 without. Both animals were right in well over 90% of cases
Understanding our primate ancestors’ relationship with alcohol can inform its use by modern humans.
When we think about the origins of agriculture and crop domestication, alcohol isn’t necessarily the first thing that comes to mind. But our forebears may well have been intentionally fermenting fruits and grains in parallel with the first Neolithic experiments in plant cultivation. Ethyl alcohol, the product of fermentation, is an attractive and psychoactively powerful inebriant, but fermentation is also a useful means of preserving food and of enhancing its digestibility. The presence of alcohol prolongs the edibility window of fruits and gruels, and can thus serve as a means of short-term storage for various starchy products. And if the right kinds of bacteria are also present, fermentation will stabilize certain foodstuffs (think cheese, yogurt, sauerkraut, and kimchi, for example). Whoever first came up with the idea of controlling the natural yeast-based process of fermentation was clearly on to a good thing.
Annabelle’s family didn’t know it, but she was dying. Two hours earlier, she had ridden along in a canoe drifting through Middle Foy Lake near their Montana home. As the canoe neared the shore on this autumn day in 2010, Annabelle leapt from the vessel, as an excited Australian Shepherd is prone to do, and swam the rest of the way to the bank. Once ashore, she licked her wet fur—a casual reflex that almost spelled her undoing.
The lake water and her coat were tainted with microcystin, a liver toxin produced by some species of blue-green algae—or cyanobacteria—thriving in the water. Quick thinking, a Google search, and an experimental therapy would ultimately save Annabelle’s life, but her case spotlights a hidden danger that abounds in freshwater bodies throughout the country. One out of three US lakes harbors hazardous levels of toxin-releasing cyanobacteria, according to the Environmental Protection Agency (EPA).