Are there any circumstances in which the sight of a rat feels welcome, even in the wild?
Probably not, but I’m trying hard to learn to admire their ingenuity and brazenness.
In a public park nearby, they’ve become a familiar sight near the waterways and rubbish bins, hoovering up the remnants of sandwiches and duck food.
But last year I noticed they had taken a liking to a big oak tree that grows on the field’s periphery. I had always diverted my route to walk by the oak, and one day, while admiring the bark of the old tree, I was startled by the presence of a plump brown rat which scuttled away – a little too slowly for comfort – across the ground ivy around the base of the trunk.
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I cursed it for ruining my walk but, given I spot one nearly every time, I admitted defeat. Are there reasons to like rats – perhaps even feel sorry for them – instead?
I take a look at one of the most extraordinary battles between predator and prey, captured 10 years ago by wildlife photographer Paul Hughes in a short film, The Grey Heron Versus The Brown Rat.
Rats don’t stand a chance against herons, which can appear galumphing and ungraceful – all gangly legs and sinuous necks – but which are Olympic-level hunters. The heron in this footage leans across the riverbank and stares intensely at the overhanging ivy. And then, with a short spear-like movement of its long bill, it flaps into the water while, at lightning speed, it grabs an unsuspecting brown rat from the vegetation.
An eight-minute masterclass in predation ensues as the rat desperately attempts to escape the heron’s tight grip on its front paw. The heron, confident the rat will soon be in its tummy, appears in no hurry but, almost bored, moves things on a bit by ducking the rat into the fast-flowing water.
Soaking wet, the rat tries to bite the tip of the heron’s bill. The heron chucks it under the cold water again, and then, with a final throw of its head, the rat’s fate is sealed; the heron swallows it in one gulp, its neck pulsing with life. Far from feeling sorry for the blighter, it was a relief to see it gone.
It was a brown rat that found itself in the heron’s stomach. We’ve two species of rats in Ireland, both non-native. The agile, slim black rat first came here aboard ships in the Middle Ages. It was all but displaced by the larger and stronger brown rat, originally from the Far East, which arrived sometime in the early 1700s and, within a decade, had sealed its reputation as a pest.
They can breed from spring to late winter and one female can produce up to 50 babies a year. Since then, rats have transmitted dangerous and potentially fatal diseases; they’ve eaten their way through stored food and damaged infrastructure such as wires and buildings.
They’re so intertwined with humans and our untidy ways that it’s easy to forget rats can exist in the wild under more natural conditions and will travel a few kilometres a night in search of food, which they then store for eating later. Along the way, they’re a vital food source for barn owls.
Rats are clever. Dr Manon Schweinfurth of St Andrews School of Psychology and Neuroscience has spent her career studying them, and says they are incredibly social animals who groom each other, share food and have a high propensity to co-operate and reciprocate.
She has conducted experiments using 19-month-old male rats. After 15 months of separation, the rats recognised their relatives by body odour alone, and Dr Schweinfurth discovered that rats will be more helpful to others who are nice to them, above and beyond whether they are related.
They remember these ‘nice’ acts for a long time and will exchange different commodities, such as offering to groom each other’s fur. It takes significant brain power to recognise and remember the identities and behaviour of other rats in the past, but they appear to be able to do this and operate under the tit-for-tat rule of “I help you because you helped me”.
Their cognitive capacities stretch to playing complex games. In 2019, researchers put adolescent male rats in a 30-metre squared room and, over two weeks, taught them a game of hide and seek against a human experimenter, with a reward of ‘tickling’ instead of food.
The rats were more than up for it. As the seeker, the rats undertook a thorough search of the area. When it was time to hide, they learned to keep quiet and quickly learned to select opaque hiding places instead of transparent boxes. When discovered, they even exhibited “joy jumps” and squealed. According to the lead scientist, neurobiologist Michael Brecht of Berlin’s Humboldt University, ‘they look like they’re having fun’.
Back on my walk, as I near the oak tree, I try to flood my mind with teenage rats playing peekaboo and the billions of lab rats in research who’ve helped to reduce human suffering and increase longevity. (It’s estimated that one study per hour that used rats as model organisms is published worldwide.)
But then – ugh! – I spot another brown rat lolloping about and yelp in shock. Around the tree, I see small black bags of dog poo – sacs of plastic packed inside with fats and proteins – and wonder what on earth this clever rat must think of humans and our slovenly ways. My heart racing, I scuttle away as fast as I can.
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