Thinking in vain...

Starving Snakes Eat Their Hearts Out

Aug. 20, 2007 — Certain snakes can survive without food for two years at a time, but not without paying a physical price, according to a new study that found some snake species will actually digest their own hearts and grow bigger heads to broaden prey options during periods of famine.

The study, which will be published in next month's issue of Zoology, is the first ever to examine starvation physiology in snakes.

Author Marshall McCue, a researcher in the Department of Biological Sciences at the University of Arkansas, thinks intense snake hunger may even explain some of the more outrageous snake stories from recent years.

"Severe hunger might make snakes take greater risks than otherwise," said McCue, who then mentioned "last year's photos of the Everglades python eating the alligator and then lethally 'popping' open, or stories of escaped pet snakes eating unusual objects, like unused light bulbs."

For his study, McCue put 20 ball pythons, 22 ratsnakes and 20 western diamondback rattlesnakes through 168 days of starvation. Weight and other measurements were taken at regular intervals. After the 168 days, McCue chemically euthanized each snake and pureed it in a blender in order to better conduct chemical analysis.

At the 168th day, the snakes lost 9.3 to 24.4 percent of their initial body mass. They also reduced their energy expenditures by an average of 80 percent over the test period. McCue told Discovery News that the snakes usually were sedentary, wrapped up in provided "hide boxes," and only explored their environments when they thought a potential food source was around.

Measurements revealed the snakes actually grew longer during the fast. Growth especially was noticed in the head.

"Larger head bones mean that they can choose from a wider range of potential prey items," he said, noting that snakes cannot chew and therefore must be able to swallow whole animals.

The chemical analysis determined the snakes break down saturated fatty acids into polyunsaturated fats by "picking off bits of hydrogen for energy."

Intestinal fat, which he likened to "belly fat" in humans, as well as fatty liver tissues were among the first to be targeted. As a byproduct, water formed in the snakes' bodies, causing them to "bloat" by around 7 percent.

Then the snakes would digest their own heart muscle.

The heart breakdown initially surprised McCue, but he said it is reasonable given that "the lower energy expenditure allows lower circulatory demands, and therefore permits the heart organ to shrink."

Immediately following a nutritious meal, the snake hearts can quickly rebuild themselves.

Aaron Rundus, a University of Nebraska researcher who has also studied snakes, said he was surprised to learn snakes can survive without eating for up to two years, but, "I completely believe it, and the physiological mechanisms make sense given how successful these reptiles are at surviving under the worst of conditions."

Rundus explained to Discovery News that snakes are "ambush hunters," as opposed to "strategists," so they must wait for incredibly long periods before an unsuspecting victim may cross their paths.

McCue hopes future studies on snake starvation will lead to treatments that can increase food deprivation tolerance in other animals, including humans.

Via discovery.com