We were walking along Willows Beach, hopping from log to log. Suddenly one of the shorter logs we were just about to step on, animated itself, leaping up and running away. Even before consciously registering that this was no log but a large round rat, my friend and I ran screaming to the safety of the sidewalk.
What is it about rats that elicits such fear and revulsion? I once saw someone taking a pet rabbit for a walk on a leash at this same spot, and thought it cute. These two furbearers are comparable in size, both breed with indecent fecundity and both are capable of biting (a relative of mine needed antibiotics after being bitten by a pet rabbit), yet we don’t view them the same way, and this even though by all accounts rats are far more intelligent than rabbits. Logically, we should admire them.
In laboratories rats have been shown to play and laugh like human children, although they laugh outside our hearing range (researchers hear them by using a bat detector to convert frequencies of signals). They laugh when tickled and come back for more, and they play by chasing and wrestling with each other.
Those who are separated in isolated cages spend their time sleeping and acting depressed, and do less well on intelligence tests.
Lab rats have been selectively bred over the years from albino varieties of the Norway or brown rat. That (a.k.a the sewer rat) and the smaller black rat, imaginatively named Rattus rattus, are the two types found throughout our region. Both came originally from Asia and are thought to have reached western Europe by the first century AD. They reached North America on ships in 1750-55.
Prof. Jaak Panksepp studies the white Norway rat’s playful hilarity in his labs just south of us at Washington State University. Their emotions originate in the primitive (earliest evolved) part of their brain, which is shared with us and all animals. Their moods can be altered by chemically stimulating this brain region, which is why we use them to test psychiatric and other drugs – to their vast misfortune. They’re too much like us for their own good.
Prof. Panksepp has discovered that play triggers the proteins that make rats’ brain cells grow, facilitating socialization. However, overcrowding has been shown to stimulate the aggression parts of their brains, even when food is plentiful.
A female in the wild has up to five litters per year of seven to 14 babies. All this playful socializing and intelligence has helped rats spread across the globe as generalist omnivores eating everything from scraps to seeds to small birds and animals. They also devour crops and spread germs, which tends to occlude for us the charm of their playfulness.
Rats reach maturity at five weeks and usually live only a few years, but they make the most of their time. Apparently, burrowing and breeding in our stream-banks, compost piles, pipes and crawlspaces, keeping us awake at night and terrorizing us at the beach, rats just want to have fun. If only they’d stop darting and gaze at us like raccoons do, or had fluffy tails like a squirrel’s, we might fear them less. Maybe one day scientists will study what evolutionary purpose that long snaky tail has, and which section of the human brain houses our inherent revulsion at it.
Barbara Julien is a local writer and nature enthusiast. She writes here monthly about the various species making their home in Oak Bay.