Quick! What's Gray and Huge and as Drunk as a Skunk?

Cats do it. Lab rats do it. Even water buffalo do it.

Get looped, that is.

"The mongoose, when grieving over the loss of a mate or when its burrows are wiped out by a monsoon, will very often eat a plant that has psychedelic qualities," says Ronald K. Siegel, a UCLA psychopharmacologist who has studied drug use in animals for 25 years and who wrote "Intoxication: Life in Pursuit of Artificial Paradise" (Dutton, 1988).

Elephants, when stressed from the pressure of poachers, thinning of the herd or competition from other animals, become intoxicated from eating fermented marula fruit, he says. "And they act in a very unelephant-like way. They act like people . . . become very aggressive, isolate themselves or become passive."

Siegel has observed a water buffalo eating poppies and lab rats given access to alcohol that drank the most before feeding ("the cocktail hour effect") and before going to sleep ("the nightcap effect").

Just as human beings have pursued altering their minds since prehistoric times (archeological remains, pictographs and linguistic analysis suggest early man delved into mind-altering drugs), so have animals and even insects, says Siegel, by ingesting fermented fruits, vegetables and other substances.

"The behavior is really universal," he says. "We share the same motivations and desires." Siegel characterizes the urge to alter one's perceptions of reality as a "fourth drive," following sex, hunger and thirst.

And once animals--and people--discover the pleasurable effects of a substance, they go to considerable trouble to revisit that particular well of pleasure again and again.

"Animals do it for the same reasons people do," says Siegel, "to change the way they feel. We are chemical organisms. Our brain is nothing more than a 3-pound sack of chemicals with natural opiates and stimulants more powerful than cocaine or opium. It is natural that we will have an affinity to natural and artificial substances that strike a resonance."

Scientists are just beginning to understand the drive to repeatedly seek out intoxicants. By using brain-scanning technology, researchers have been able to determine that the pleasurable feelings evoked by certain drugs and by alcohol are caused by a surge of the neurotransmitter dopamine, which ferries messages from one neuron in the brain to another.