Polymaths are sometimes not easy people, especially when they are always right. I can imagine my cousin, Sheila Sowter, who has died aged 81, excelling as Frank Sinatra’s penance while teaching him the opera-trained version of My Way.

She was played in to her humanist woodland funeral to the sound of The Mikado’s Willow, Tit Willow and out to Ride of the Valkyries, the ceremony attended by friends from all walks of her life – Mensa members, Wagnerians, Open University teachers and students, locomotive and railway buffs, fancy ratters, edible dormouse population assessors and multilinguists.

Sheila was born in Duffield, Derbyshire, to Percy, an industrial chemist and morris dancer, and Connie, a teacher. Her state scholarship and exhibition to Newnham College, Cambridge, to study the natural sciences tripos, ended with a gentleman’s degree, rather than the expected first, perhaps due to the time she devoted to cricket (she was awarded a half blue), the Magic Circle and other distractions.

She chose to be a single parent at a time when it was both unusual and a brave move, and in due course, her daughter, Connie, asked for a pet mouse. Instead Sheila brought home a female rat, for which she borrowed a buck, and started a family.

She became fascinated by rat genetics and joined the National Fancy Rat Society, which she served as a national and international show judge. Her quest for the perfect hooded rat, with an even stripe down the back, in any and every colour combination, led her to establish the Flaxholme stud at her home in Brentwood, Essex.

Sheila liked to say: “She who can does, she who can’t teaches, and she who can’t teach teaches teachers,” which she did, having obtained an MA in the psychology of education from the University of London. From 1967 she taught initially basic science and latterly earth science at Avery Hill College, which became part of the University of Greenwich, retiring in 1992, and part-time for the Open University, retiring in 1998. She also took an MA in Mathematics from the OU in 1998.

She travelled widely over the years – she was visiting Czechoslovakia in 1968 when the Russians invaded, and got out by stopping a train. It turned out she spoke Czech, Russian and German.

She is survived by Connie and her grandchildren, Laura and Ben.