Biologists working in South Africa's Kruger National Park are perplexed over a recent spate of crocodile deaths. At least 30 of the big reptiles have died in the last few months, each with one thing in common: hardened, fatty deposits in their tails.

"We suspect that because of the hardening fat in the tails, the animals could no longer swim and so sank and drowned," park spokesmen William Mabasa told New Scientist magazine.

Tests suggest the crocodiles suffered from a condition called pansteatitis, which is caused by eating rotten or rancid fish. But park ecologists say the fish in the Olifants River, where the crocodile deaths have occurred, appear healthy, and no other animals in the river seem to be affected.

An alternative possibility is more worrisome: The crocs are being exposed to deadly pollutants. The Olifants is considered to be the most polluted river in Kruger.

WATER WASTERS

The magazine Scientific American recently released its list of gluttonous water practices:

1. Dish-washing by hand. With the water running, you use 20 to 40 gallons. Modern electric dishwashers need less than 10 gallons per average load.

2. Washing your car at home. That Saturday morning ritual can easily go through 80 to 140 gallons, compared with 30 to 45 at a commercial car wash, which also recycles the water.

3. Pools. A swimming pool can lose as much as 1,000 gallons per month to evaporation, depending upon local weather conditions and overall water surface. A lot can also be lost underground, due to cracks, liner tears and leaking pipes. It's hard to know how many pools lose water this way. Estimates vary, but some go as high as one in three pools.

4. Water sprinklers. To keep lawns green and gardens lush, sprinklers can dispense as much as 265 gallons an hour — comparable to what an average U.S. household uses daily.

5. Desert resorts. Water consumption on the Las Vegas Strip is pretty conspicuous, but it actually accounts for just 3 percent of local use. The bigger culprits are the 60-plus local golf courses and countless residential lawns, which consume a whopping 70 percent of the city's water supply.

VERBATIM

When I was growing up, they would ask things like: How do you fit in a test tube?

— Louise Brown, the world's first "test-tube baby" (in vitro fertilization), who celebrated her 30th birthday earlier this month

BRAIN SWEAT

What is one-half of two-thirds of three-fifths of 240 divided by one-half?

PRIME NUMBERS

$8 billion — Estimated cost of a proposed 2018 mission to retrieve rock and soil samples from Mars

$900 million — Cost of the combined Spirit and Opportunity rover missions to Mars

1 — Approximate weight, in pounds, of the Martian rock and soil samples that would be returned to Earth

Sources: NASA; New Scientist

BRAIN SWEAT ANSWER

96. One-half times two-thirds times three-fifths equals six-thirtieths or one-fifth. One-fifth multiplied by 240 equals 48. Forty-eight divided by one-half equals 96.

'TRUE FACTS'

Generally speaking, the human brain can hold only three working memories at a time. Adults expand this rather pitiful capacity by grouping things into hierarchical categories, such as phone numbers in numerical clusters. Researchers recently discovered babies do something similar, automatically categorizing objects to improve their working memory capacity.

ELECTRON INK

Frank R. Paul Gallery

frankwu.com/paul1.html

Frank Paul (1884-1963) was one of the first — and still among the best —illustrators of science fiction. The first science fiction painting Arthur C. Clarke ever saw was a Paul image. You can check out Paul's work here, particularly the covers for "Amazing Stories," the first popular magazine devoted entirely to science fiction. It debuted in 1926; the last issue appeared in 2005.

QUIRKS OF NATURE

Neuroscientists have discovered sloths in the wild sleep around 9.5 hours a day, far less than the previous estimated average of 16 hours. That number, say experts, was based on studies of captive sloths, who may simply have been bored and depressed.

JUST ASKING

Why do fat chance and slim chance mean the same thing?

POETRY FOR SCIENTISTS

There was a computer that cried

I can think, somehow, deep down inside.

I know it's official

Because I have "Dell artificial

Intelligence" stamped on my side.

— Terry Wilson

ANTHROPOLOGY 101

Among the Tartars, families of the bride and groom would traditionally divide into two groups after the marriage and fight, the battle continuing until some of the participants suffered bleeding wounds. It was thought this ceremonial flow of blood ensured the new couple would have strong sons.

To find out more about Scott LaFee and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.