Bears – Melatonin

Science Diary: Bears – Melatonin

Music; Ambience: bear

JW: “The organ that even produces melatonin is quite small even smaller than a human. So, it’s interesting in that you don’t think humans are seasonal, but yet they have a larger pineal gland, which is the organ that produces melatonin, than bears do.”

JM: Even on a lazy Sunday morning, most humans don’t tend to sleep more than 10 hours or so; whereas bears can settle in for a long winter’s nap for weeks or months at a time without a problem. Well, that’s one reason why scientists are mystified by the bears’ apparent lack of melatonin, a chemical that regulates an animal’s sleep and wake cycles. Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside. Heiko Jansen and Jasmine Ware of Washington State University are studying bear behavior. Right now we’re listening to the sound of a wide awake bear.

JW: “We’ve measured melatonin, which is widely considered one of the most reliable mediators of these environmental signals. So, as daylight or light comes into the animal, it goes into the brain and then causes a series of signals, and that is manifested in the production of melatonin throughout the body. So far, we think that the bears aren’t making very much melatonin.”

HJ: “We discovered how small the bear pineal gland was. And it’s really quite remarkable in-in its small size, but may fit with what we’re seeing in terms of the hormone that it supposedly produces and there being very, very little-those levels. They’re far lower than anything we’ve measured in either sheep, hamsters, or rat blood.”

JM: So without substantial melatonin production, how do bears regulate their cycle of waking and sleeping? Jansen and Ware believe there may be a number of factors involved, including a bear’s ability to take cues from changes in sunlight. We’ll hear more in future programs. Pulse of the Planet’s Science Diaries are presented by the National Science Foundation.

Bears - Melatonin

Melatonin regulates the sleep-wake cycle for humans and other animals. Strangely, bears who are masters of hibernation, seem to produce very little melatonin.
Air Date:06/16/2015
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Transcript:

Science Diary: Bears - Melatonin

Music; Ambience: bear

JW: "The organ that even produces melatonin is quite small even smaller than a human. So, it's interesting in that you don't think humans are seasonal, but yet they have a larger pineal gland, which is the organ that produces melatonin, than bears do."

JM: Even on a lazy Sunday morning, most humans don't tend to sleep more than 10 hours or so; whereas bears can settle in for a long winter's nap for weeks or months at a time without a problem. Well, that's one reason why scientists are mystified by the bears' apparent lack of melatonin, a chemical that regulates an animal's sleep and wake cycles. Welcome to Pulse of the Planet's Science Diaries, a glimpse of the world of science from the inside. Heiko Jansen and Jasmine Ware of Washington State University are studying bear behavior. Right now we're listening to the sound of a wide awake bear.

JW: "We've measured melatonin, which is widely considered one of the most reliable mediators of these environmental signals. So, as daylight or light comes into the animal, it goes into the brain and then causes a series of signals, and that is manifested in the production of melatonin throughout the body. So far, we think that the bears aren't making very much melatonin."

HJ: "We discovered how small the bear pineal gland was. And it's really quite remarkable in-in its small size, but may fit with what we're seeing in terms of the hormone that it supposedly produces and there being very, very little-those levels. They're far lower than anything we've measured in either sheep, hamsters, or rat blood."

JM: So without substantial melatonin production, how do bears regulate their cycle of waking and sleeping? Jansen and Ware believe there may be a number of factors involved, including a bear's ability to take cues from changes in sunlight. We'll hear more in future programs. Pulse of the Planet's Science Diaries are presented by the National Science Foundation.